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What are Pipes Solutions

What are steel pipes?

Table of Contents

Steel pipe is a long strip of steel with a hollow cross-section and no peripheral joints. It is widely used in the manufacture of structural and mechanical parts, such as oil drilling rods, automotive drive shafts, bicycle frames and steel scaffolding used in building construction. Steel pipe manufacturing ring parts, can improve material utilization, simplify the manufacturing process, saving materials and processing hours, such as rolling bearing rings, jack sets, etc., has been widely used to manufacture steel pipe. Steel pipe is also a variety of conventional weapons indispensable materials, gun barrels, barrels, etc. to steel pipe to manufacture.

Types of steel pipe

Steel pipe can be divided into seamed steel pipe and seamless steel pipe.
Seamless steel pipe is made of whole round steel perforated with no welded seam on the surface, called seamless steel pipe. According to the production method, seamless steel pipe can be divided into hot-rolled seamless steel pipe, cold-rolled seamless steel pipe, cold-drawn seamless steel pipe, extruded seamless steel pipe, top pipe, etc. According to the shape of the section, seamless steel pipe is divided into two kinds of round and shaped, shaped pipe has a square, oval, triangular, hexagonal, melon, star, with a variety of complex shapes finned tube. Depending on the application, there are thick-walled seamless steel tubes and thin-walled seamless steel tubes. Seamless steel tubes are mainly used as petroleum geological drilling tubes, petrochemical cracking tubes, boiler tubes, bearing tubes, and high-precision structural steel tubes for automobiles, tractors, and aviation.
Seamed steel pipe, also known as welded pipe, is divided into straight seam welded pipe and spiral welded pipe, which is a steel pipe made of steel plate or steel strip that has been rolled and formed and welded. Welded steel pipe production process is simple, high production efficiency, a variety of specifications, less equipment capital, but the general strength is lower than seamless steel. Uses include: low pressure fluid transfer pipe, ordinary carbon steel wire casing, straight seam welded steel pipe, galvanized welded steel pipe for low pressure fluid transfer, spiral submerged arc welded pipe for pressurized fluid transfer, spiral high frequency welded steel pipe for pressurized fluid transfer, spiral submerged arc welded steel pipe for general low pressure fluid transfer, spiral welded steel pipe for piles.

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Seamless steel pipe

Seamless Steel Pipe is made from a solid round steel ‘billet’ which is heated and pushed or pulled over a form until the steel is shaped into a hollow tube.
Seamless pipes are finished in accordance with customer needs regarding dimensional and wall thickness specifications as well as heat treatment for more demanding applications. In general a seamless pipe is manufactured in sizes from 1/8” to 24” according to current standards API, ASTM, and ASME.
In the production of steel pipes, steel is molded and reshaped with different machinery at different temperatures. One of the steel manufacturing processes is steel rolling, which involves metal stock passing through a pair of rolls. Rolling produces flat steel sheets of a specific thickness, and the process is classified according to the temperature at which the metal is rolled. If the temperature of the metal is above its recrystallization temperature, or the temperature at which the grain structure of the metal can be altered, then the process is termed as hot rolling. If the temperature of the metal is below its recrystallization temperature, the process is termed as cold rolling.

Cold Drawn Seamless Pipe

Cold drawn seamless pipe is usually required where the end product is either safety and/or quality critical.
The method for making cold-drawn seamless pipes involves taking a round “billet” or bar of steel and boring it in the center, turning it, cutting it, heating it to make it more pliable, then “drawing” it (extruding or pulling it) to make it a longer and thinner pipe. As the pipe cools, “cold working” begins. Cold working involves pulling the pipe over a stationary die and a mandrel. This increases the pipe’s hardness and improves its surface condition and grain structure while reducing the pipe to the desired size and thickness.
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Hot-Rolled Seamless Pipe

Different from cold rolling which is performed below the recrystallization temperature, hot rolling is conducted above the temperature. Hot rolled seamless pipes offer higher torsional rigidity than cold rolled ones, thus it offers better torsional resistance than cold rolled tubes.

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Advantages
Hot rolled seamless steel pipe can damage the cast microstructure of the steel ingot, refinement of the crystal grains of the steel, and eliminate the defects of the microstructure, so that the the steel organization compacting, improve the mechanical properties. This improvement is reflected in the rolling direction, so that the steel is no longer to a certain extent isotropic; pouring the formation of bubbles, cracks, and osteoporosis, under high temperature and pressure can also be welded together.
Disadvantages
• After the hot rolling, the nonmetallic inclusions in the interior of a steel (mainly sulfides and oxides, as well as the silicate) was pressed into a sheet, stratified (laminated) phenomenon appears. The layering of the steel in the thickness direction by the pull performance deteriorated significantly, and may appear in the weld shrinkage interlayer tear. Weld shrinkage induced local strain often reach several times the yield point strain, the strain is much greater than the load caused;
• Residual stress caused by uneven cooling. The residual stress is the stress of internal self-phase equilibrium in the absence of external force, the hot-rolled steel of various cross-sectional has a residual stress such Usually steel sectional dimension is the greater, the greater the residual stresses. Residual stress is self-phase equilibrium, but the steel members in the performance external force or have a certain influence. Such as deformation, stability, anti-fatigue may adversely.
• Hot-rolled steel products, poor control of thickness and edge width. We are familiar with the thermal expansion and contraction, even if the beginning of the hot-rolled out are standard length, thickness, or there will be some negative final after cooling, this negative differential edge width wider the increasing thickness of the performance of the more obvious.

Specification of the Seamless Pipes

• Pipe sizes are documented by a number of standards, including API 5L ANSI/ASME B36.10M in the US, and BS 1600 and BS 1387 in the United Kingdom. Typically, the pipe wall thickness is the controlled variable, and the Inside Diameter (I.D.) is allowed to vary. The pipe wall thickness has a variance of approximately 12.5 percent.
• Specifications for API 5L adhere to the International Organization for Standardization ISO 3183, standardizing pipeline transportation systems within the materials, equipment and offshore structures for natural gas, petroleum, and petrochemical industries. When authoring the standards, the technical committee recognized that there are two basic Product Specifications Levels (PSL) of technical requirements and therefore developed PSL 1 and PSL 2. PSL 1 is a standard quality for line pipe where PSL 2 contains additional chemical, mechanical properties, and testing requirements.
• PSL-1 is a loose standard quality for line pipe, whereas PSL-2 contains additional testing requirement, stricter chemical physicals, along with different ceiling limits of mechanical properties, and require Charpy impact testing conditions.
• ASTM A 530/A 530M Specification for General Requirements for Specialized Carbon and Alloy Steel Pipe.

Cost of the Seamless Pipes

• Hot rolling is typically not as costly or as expensive as cold rolling or cold drawing, as the steel is more malleable at a higher temperature. There is also one less step when producing the steel, which cuts back on the operating costs of producing the steel. The finish of the steel will not be as smooth or clean as cold rolled or drawn steel, and mechanical properties of the steel are typically not as good as steel in its cold drawn form. This often is not important for steel products that are produced in high quantity and do not need a clean external finish.

Size of the Seamless Pipes

• Outer Diameter:
Hot finish: 2″ – 30″,Cold drawn: 0.875″ – 18″
• Wall Thickness:
Hot finish: 0.250″ – 4.00″,Cold drawn:0.035″ – 0.875″
• Length:
Random Length, Fixed Length, SRL, DRL
• The European designation equivalent to NPS is DN (Diamètre Nominal/ nominal diameter). The pipe sizes are measured in millimeters.
For NPS of 4 and larger, the DN is equal to the NPS multiplied by 25 (not 25.4)

Heat Treatment of the Seamless Pipes

• Hot-finished pipe need not be heat treated.
• Cold-drawn pipe shall be heat treated after the final cold draw pass.

Test of the Seamless Pipes

• Chemical Component Analysis, Mechanical Properties (Ultimate tensile strength, Yield strength, Elongation), Technical Properties (Flattening Test, Flaring Test, Bending Test, Hardness Test, Blow Test, Impact Test etc), Exterior Size Inspection.

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Seamed steel pipe

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Longitudinally Welded and Double SAW

Welded pipe (pipe manufactured with a weld) is a tubular product made out of flat plates, known as skelp, that are formed, bent and prepared for welding. The most popular process for large diameter pipe uses a longitudinal seam weld or Longitudinally Submerged Arc Welded Steel pipes (LSAW).
DSAW Pipe is often produced by automatic double-wire double-sided submerged arc welding process. DSAW pipe is simple, high efficiency and low cost. In the steel pipe forming steel plate deformation evenly, the residual stress is small, does not appear to scratch the surface of the phenomenon. The diameter and thickness of the steel pipe size specifications can be used flexibly in the production of large diameter thick seam steel pipe. In the production, welding joint can be pre-heated before welding inside and outside, to ensure that the quality of process is liable.
For transporting large quantities of hydrocarbons over long distances, longitudinal submerged arc welded (LSAW) pipes have been used for decades. When operational conditions require high wall thickness due to high internal or external pressures, LSAW pipes are commonly the most economical solution. Offshore pipelines link platforms at subsea wells with the processing devices onshore. Environmental and population safety aspects trigger high‐quality requirements and appeal to the responsibility of all involved bodies to put all efforts into safe pipeline operation.
Double Submerged Arc Welded (DSAW) steel pipe is available in straight and spiral welded formats and used in a variety of applications. The submerged welding process protects the steel from contamination of impurities in the air. The manufacturing of Double Submerged Arc Welded Pipe involves first forming steel plates into cylindrical shapes. Then the edges of the rolled plate are formed so that V-shaped grooves are formed on the interior and exterior surfaces at the location of the seam. The pipe seam would then be welded by a single pass of an arc welder on the interior and exterior surfaces. The welding arc is submerged under flux.
Specification of the Longitudinally Welded Pipes
• ASME 36.10, ASME 36.19 are the key specifications covering the standardization of dimensions of welded and seamless wrought steel pipe. ASME B16.25 covers the preparation of butt weld connections between pipes and ASME B16.49 covers the marking details.
• Specifications for API 5L adhere to the International Organization for Standardization ISO 3183, standardizing pipeline transportation systems within the materials, equipment and offshore structures for natural gas, petroleum, and petrochemical industries. When authoring the standards, the technical committee recognized that there are two basic Product Specifications Levels (PSL) of technical requirements and therefore developed PSL-1 and PSL-2. PSL-1 is a standard quality for line pipe where PSL-2 contains additional chemical, mechanical properties, and testing requirements.
• PSL-1 is a loose standard quality for line pipe, whereas PSL-2 contains additional testing requirement, stricter chemical physicals, along with different ceiling limits of mechanical properties, and require Charpy impact testing conditions.
Advantage of the Longitudinally Welded Pipes
• The submerged welding process protects the steel from contamination of impurities in the air
• What can be known as an advantage of this process is that welds would penetrate 100% of the pipe wall and produce a very strong bond of the pipe.
Disadvantage of the Longitudinally Welded Pipes
• Residual stress caused by uneven cooling. Residual stress is the internal self-balance stress in the absence of external force. The hot-rolled steel in all cross-sections has such residual stress. The larger the general section size, the more residual stress. Although the residual stress is self-balanced, the steel components under the action of external force or have a certain impact, such as deformation, stability, fatigue and other aspects may have an adverse effect.
Cost of the Longitudinally Welded Pipes
• When operational conditions require high wall thickness due to high internal or external pressures, LSAW pipes are commonly the most economical solution.
Length of Pipes of the Longitudinally Welded Pipes
• Piping lengths from the factory not exactly cut to length but are normally delivered as:
○ Single random length has a length of around 5-7 meter
○ Double random length has a length of around 11-13 meter
Shorter and longer lengths are available, but for a calculation, it is wise, to use this standard lengths; other sizes are probably more expensive.
Other Properties of the Longitudinally Welded Pipes
• The manufacturing of Double Submerged Arc Welded Pipe involves first forming steel plates into cylindrical shapes. Then the edges of the rolled plate are formed so that V-shaped grooves are formed on the interior and exterior surfaces at the location of the seam.
• For the ends of pipes are 3 standard versions available.
○ Plain Ends (PE)
○ Threaded Ends (TE)
○ Beveled Ends (BE)
The PE pipes will generally be used for the smaller diameters pipe systems and in combination with Slip On flanges and Socket Weld fittings and flanges.
The TE implementation speaks for itself, this performance will generally used for small diameters pipe systems, and the connections will be made with threaded flanges and threaded fittings.
The BE implementation is applied to all diameters of buttweld flanges or buttweld fittings, and will be directly welded (with a small gap 3-4 mm) to each other or to the pipe. Ends are mostly be beveled to angle 30° (+ 5° / -0°) with a root face of 1.6 mm (± 0.8 mm).

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Spiral Welded

Spiral welded pipe is an alternative process, spiral weld construction allows large diameter pipe to be produced from narrower plates or skelp. The defects that occur in spiral welded pipe are mainly those associated with the SAW weld, and are similar in nature to those for longitudinally welded SAW pipe.
Spiral welded steel pipes are widely used in Oil, Natural Gas, Water and other flammable & nonflammable liquid conveyance and distribution pipelines, steel structures for construction and other general purposes by means of their wide size range.
Widely preferred longer lengths up to 18,5 m. considerably decreases the cost of pipeline construction resulting in less number of girth welds compared to shorter pipe lengths.

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Spiral Weld Pipe, as the name implies, is a steel pipe that has a seam running its entire length in a spiral form.
In the past, due to the method of manufacture, Spiral Welded pipe was relegated to low pressure and structural applications. With the development of the Submerged Arc Welding process, the production of large hot rolled coils of sufficient width and the development of dependable non-destructive testing methods, it is now possible to produce Spiral Weld pipe for high-pressure service.
Present Spiral Weld mills consist of a de-coiling device (in the case of strip base material) or a plate preparation table (where the base material is in plate form) a strip connecting welder, straightening rollers, edge preparation tools (shearing and trimming), prebending devices, a three roller bending and cage forming system, an internal welder, an external welder (both Submerged Arc), ultrasonic testing apparatus and cutting devices.
The material passes through all these production stages continuously. The angle between the flat strip being fed into the machine and the finished pipe leaving the machine controls the pipe diameter in ratio to strip width and the angle of the weld in the pipe.
Because of the method of manufacture, a wide variety of diameters can be produced. The diameter tolerance is small, particularly with regard to ovality; and the pipe, due to its axial symmetry, has an inherent straightness. The length range is infinite and is controlled only by the economics of transportation.

Specification of the Spiral Welded Pipe
• ASME 36.10, ASME 36.19 are the key specifications covering the standardization of dimensions of welded and seamless wrought steel pipe. ASME B16.25 covers the preparation of butt weld connections between pipes and ASME B16.49 covers the marking details.
Advantage of the Spiral Welded Pipe
• Customize size that meet exact design requirement (Diameter, Thickness, Length).
• Greater strength, double welded seam has the effect of a spiral band around the pipe.
• Greater pressure resistant, Stress, and Friction. The spiral band has the effect of adding greater structural strength, 25% higher pressures than longitudinally welded pipes and ERW Pipes.
Disadvantage of the Spiral Welded Pipe
• Spiral pipe is harder to weld.
• Spiral pipe have a longer weld and are therefore prone to more failures.
• Spiral pipe are more exposed to propagating cracks.
• Spiral pipe have problems in pigging operations.
Length of the Spiral Welded Pipe
• Piping lengths from the factory not exactly cut to length but are normally delivered as:
○ Single random length has a length of around 5-7 meter.
○ Double random length has a length of around 11-13 meter.
Shorter and longer lengths are available, but for a calculation, it is wise, to use this standard lengths; other sizes are probably more expensive.
Other Properties of the Spiral Welded Pipe
• An effective pre and post weld heat treatment is vital. The use of pre heat together with a carefully selected surface preparation and the use of low hydrogen, hydrogen tolerant consumable wire eliminate the risk of hydrogen cracking during welding. Post weld heat treatment is used to control the more significant problem of the transformation of the substrate to un-tempered martensitic structure during the process.

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Electric Resistance/ Fusion Welded (ERW And EFW)

Electric resistance welding (ERW) refers to a group of welding processes such as spot and seam welding that produce coalescence of faying surfaces where heat to form the weld is generated by the electrical resistance of material combined with the time and the force used to hold the materials together during welding

Electric Fusion Welding (EFW) steel pipe refers to an electron beam welding, the use of high-speed movement of the electron beam directed impact kinetic energy is converted to heat the workpiece so that the workpiece leaving the melt, the formation of the weld.

ERW

ERW steel pipe is manufactured through low or high frequency resistances Electric Resistance. Welding seam is in longitudinal. During the ERW pipe welding processes, the electric current will make the heat when flow through the contact surface of the welding area. It will heat the 2 edges of the steel to a point that the edges can form a bond. Meanwhile with the combined pressure, the edge of the pipe billet steel melted and extruded together.
ERW steel pipe used for transporting gas and liquid objects such as oil and gas, could meet the low and high pressure requirement. In recent years, with the development of ERW technology, more and more ERW steel pipe used in the oil and gas fields, automobile industry and so on.
ERW pipe manufacturing process includes HFW. ERW have low, medium, high frequency welding processes, and HFW is especially for high-frequency electric resistance welding. The differences between ERW and HFW steel pipe, is EFW is a type of ERW process for ordinary and thin-wall thickness steel pipes.
HFW
High frequency welding (HFW) steel pipe is that ERW pipe produced with a welding current frequency equal to or greater than 70 kHZ. Through high-frequency current welding resistance, the heat generated in the contact objects, so the objected surface are heated to the plastic state, then with or without forging to achieve a combination of steels. HFW is a solid resistance heat energy. The high frequency current pass through the metal conductor, will produce two peculiar effects, skin effect and proximity effect. And HFW process is to use the skin effect to concentrated on steel object surface, use proximity effects to control the position and the power of the high-frequency electric current flow path. Since the speed is very high, the contacted plate edge could be heated and melted in shore time, then extruded through docking process.
EFW

Electric Fusion Welding (EFW) steel pipe refers to an electron beam welding, the use of high-speed movement of the electron beam directed impact kinetic energy is converted to heat the workpiece so that the workpiece leaving the melt, the formation of the weld. It is mainly used for welding dissimilar steel welding sheet or which high power density, metal weldment can rapidly heated to high temperatures, which can melt any refractory metals and alloys. Deep penetration welding fast, heat-affected zone is extremely small, so small performance impact on the joints, the joint almost no distortion. But it has a requirement on a special welding room because welding using X-rays.

Specification of the ERW/ EFW Pipe
• ASME 36.10, ASME 36.19 are the key specifications covering the standardization of dimensions of welded and seamless wrought steel pipe. ASME B16.25 covers the preparation of butt weld connections between pipes and ASME B16.49 covers the marking details.
Advantage of the ERW/ EFW Pipe
• Customize size that meet exact design requirement (Diameter, Thickness, Length).
• Greater strength, double welded seam has the effect of a spiral band around the pipe.
• Greater pressure resistant, Stress, and Friction. The spiral band has the effect of adding greater structural strength, 25% higher pressures than longitudinally welded pipes and ERW Pipes.
Disadvantage of the ERW/ EFW Pipe
• Spiral pipe is harder to weld.
• Spiral pipe have a longer weld and are therefore prone to more failures.
• Spiral pipe are more exposed to propagating cracks.
• Spiral pipe have problems in pigging operations.
Length of Pipes of the ERW/ EFW Pipe
• Piping lengths from the factory not exactly cut to length but are normally delivered as:
○ Single random length has a length of around 5-7 meter.
○ Double random length has a length of around 11-13 meter.
Shorter and longer lengths are available, but for a calculation, it is wise, to use this standard lengths; other sizes are probably more expensive.
Ends of the ERW/ EFW Pipe
• For the ends of pipes are 3 standard versions available.
○ Plain Ends (PE)
○ Threaded Ends (TE)
○ Beveled Ends (BE)
The PE pipes will generally be used for the smaller diameters pipe systems and in combination with Slip On flanges and Socket Weld fittings and flanges.
The TE implementation speaks for itself, this performance will generally used for small diameters pipe systems, and the connections will be made with threaded flanges and threaded fittings.
The BE implementation is applied to all diameters of buttweld flanges or buttweld fittings, and will be directly welded (with a small gap 3-4 mm) to each other or to the pipe. Ends are mostly be beveled to angle 30° (+ 5°/ -0°) with a root face of 1.6 mm (± 0.8 mm).
Other Properties of the ERW/ EFW Pipe
• An effective pre and post weld heat treatment is vital. The use of pre heat together with a carefully selected surface preparation and the use of low hydrogen, hydrogen tolerant consumable wire eliminate the risk of hydrogen cracking during welding. Post weld heat treatment is used to control the more significant problem of the transformation of the substrate to un-tempered martensitic structure during the process.

Materials of Steel Pipes

ASTM International: American Society for Testing and Materials
This is one of the largest voluntary standards development organizations in the world. ASTM standards define the specific manufacturing process of the material and determine the exact chemical composition of pipe fittings, through percentages of the permitted quantities of carbon, magnesium, nickel, etc., and are indicated by “Grade”. This is a reputed scientific and technical organization that develops and publishes voluntary standards on the basis of materials, products, systems and services. This is a trusted name for standards. The standards covered by this organization covers various types of pipes, tubes and fittings, especially made of metal, for high-temperature service, ordinary use and special applications like fire protection. The ASTM standards are published in 16 sections consisting of 67 volumes.
UNS: Unified Numbering System
Alloy numbering systems vary greatly from one alloy group to the next. To avoid confusion, the UNS for metals and alloys was developed.
The UNS number is not a specification, because it does not refer to the method of manufacturing in which the material is supplied. The UNS indicates the chemical composition of the material.
An outline of the organization of UNS designations follows:
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Some ASTM materials are compatible with specifications from other countries, such as BS (Britain), AFNOR (France), DIN (Germany), and JIS (Japan). If a specification from one of these other countries either meets or is superior to the ASTM specification, then it is considered a suitable alternative, if the project certifications are met.

Carbon Steel & Alloy Steel

• ASTM A53 (Gr. A, B)
• API 5L Welded -Grades (B, X42, X46, X52, X56, X60, X65 and X70) PSL 1, PSL 2 (PSL2 shall be in HFW process)
• ASTM A252
• ASTM A134
• ASTM A135
• EN 10219 (S275, S355)
• A671 (CC60, CC65)
• A672 (CC60, CC65)
• ASTM A691
A53/A53M. Standard specification for pipe—steel, black and hot-dipped, zinc-coated, welded, and seamless.
A106. Standard specification for seamless carbon steel pipe for high-temperature service.
A335/A335M. Standard specification for seamless ferritic alloy-steel pipe for high-temperature service.
A524-96. Standard specification for seamless carbon steel pipe for atmospheric and lower temperatures.
A530/A530M-03. Standard specification for general requirements for specialized carbon and alloy steel pipe.
A671-96. Standard specification for electric-fusion-welded steel pipe for atmospheric and lower temperatures.
A672-96. Standard specification for electric-fusion-welded steel pipe for high-pressure service at moderate temperatures.
A691-98. Standard specification for carbon and alloy steel pipe, electric-fusion-welded for high-pressure service at high temperatures.
A179/A179M. Standard specification for seamless cold-drawn low-carbon steel heat-exchanger and condenser tubes.
A210/A210M. Standard specification for seamless medium-carbon steel boiler and superheater tubes.
A334/A334M. Standard specification for seamless and welded carbon and alloy-steel tubes for low-temperature service.
ASTM A519 / A519M: Standard Specification for Seamless Carbon and Alloy Steel Mechanical Tubing
ANSI / API 5L: specifies the manufacture of two product levels (PSL1 and PSL2) of seamless and welded steel pipe for the use of a pipeline in the transportation of petroleum and natural gas.
A53/A53M-02. Standard specification for pipe—steel, black and hot-dipped, zinc-coated, welded, and seamless.
A134-96. Standard specification for pipe—steel, electric-fusion (arc)-welded (sizes NPS 16 and over).
A135-01. Standard specification for electric-resistance-welded steel pipe.
A139-00. Standard specification for electric-fusion (arc)-welded steel pipe (NPS 4 and over).
A312/A312M-03. Standard specification for seamless and welded austenitic stainless steel pipes.
ASTM A178/A178M : Standard Specification for Electric-Resistance-Welded Carbon Steel and Carbon-Manganese Steel Boiler and Super-heater Tubes
ASTM A214/A214M: Standard Specification for Electric-Resistance-Welded Carbon Steel Heat-Exchanger and Condenser Tubes.
ASTM A226/A226M: Specification for Electric-Resistance-Welded Carbon Steel Boiler Super-heater Tubes for High-Pressure Service.
ASTM A423/A423M: Standard Specification for Seamless and Electric-Welded Low-Alloy Steel Tubes.

Low Temperature Carbon Steel

A333 / A333M (Gr. 1, 3, 4, 6, 7, 8, 9, 10, 11)
A333/A333M-99. Standard specification for seamless and welded steel pipe for low-temperature service.
ASTM A334 / A334M
API 5L Grades X80

Stainless Steel

ASTM A312 TP(304, 304H, 304L, 309, 310, 316, 316L, 317L, 321, 347)
ASTM A409 TP(304, 304L, 309, 310, 316, 316L, 317L, 321, 347)
ASTM B673 (UNS N08925, UNS N08354, and UNS N08926)

Duplex & Super Duplex

A312 (TP304/304L, TP316/316L, TP321, TP321H, TP347, TP347H)
A312 (UNS S31254, UNS N08367, UNS N08925, UNS N08926)
A790 (UNS S31803 / S32205 – Duplex 2205)
A790 (UNS S32550/ S32750/ S32760 – Super Duplex 2507)
A358/A358M-01. Standard specification for electric-fusion-welded austenitic chromium-nickel alloy steel pipe for high-temperature service.
A369/A369M-02. Standard specification for carbon and Ferritic alloy steel forged and bored pipe for high-temperature service.
A376/A376M-02a. Standard specification for seamless austenitic steel pipe for high-temperature central-station service.
A381-96(2001). Standard specification for metal-arc-welded steel pipe for use with high-pressure transmission systems.
A409/A409M-01. Standard specification for welded large-diameter austenitic steel pipe for corrosive or high-temperature service.
A587-96(2001). Standard specification for electric-resistance-welded low-carbon steel pipe for the chemical industry.
A789/A789M-02a. Standard specification for seamless and welded Ferritic/ austenitic stainless steel tubing for general service.
A790/A790M-03. Standard specification for seamless and welded Ferritic/ austenitic stainless steel pipe.
ASTM A213 / A213M: Standard Specification for Seamless Ferritic and Austenitic Alloy-Steel Boiler, Super-heater, and Heat-Exchanger Tubes.
A790 (UNS S31803 / S32205 => Duplex 2205)
A790 (UNS S32550/ S32750/ S32760 => Super Duplex 2507)
ASTM A249 / A249M: Standard Specification for Welded Austenitic Steel Boiler, Super-heater, Heat-Exchanger, and Condenser Tubes.
ASTM A268/A268M: Standard Specification for Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service.
ASTM A269/A269M: Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Service.
ASTM B 673: Standard Specification for UNS N08925, UNS N08354, and UNS N08926 Welded Pipe.
ASTM B 674: Standard Specification for UNS N08925, UNS N08354, and UNS N08926 Welded Tube.
ASTM A731/ A731M: Specification for Seamless, Welded Ferritic, and Martensitic Stainless Steel Pipe.

Copper Alloy

ASTM B 466
B42-02. Standard specification for seamless copper pipe, standard sizes.
B466/B466M-98 Standard specification for seamless copper-nickel pipe and tube.
B467-88: Standard specification for welded copper-nickel pipe.
B68-02. Standard specification for seamless copper tube, bright annealed.
B68M-99. Standard specification for seamless copper tube, bright annealed (metric).
B75M-99. Standard specification for seamless copper tube (metric).
B75-02. Standard specification for seamless copper tube.
B88-02. Standard specification for seamless copper water tube.
B280-02. Standard specification for seamless copper tube for air conditioning and refrigeration field service.

Titanium Alloy

ASTM B 861 Titanium Grade 1-4 is pure Titanium, the other grades are alloys. Pure Titanium is used due to its high corrosion resistance, the alloys because of the extremely high strength to weight ratio.
ASTM B 861 Grade 1. Pure Titanium, relatively low strength and high ductility.
ASTM B 861 Grade 2. The pure titanium most used. The best combination of strength, ductility and weldability.
ASTM B 861 Grade 3. High strength Titanium, used for Matrix-plates in shell and tube heat exchangers.
ASTM B 861 Grade 5. The most manufactured titanium alloy. Exceedingly high strength. High heat resistance.
ASTM B 861 Grade 7. Superior corrosion resistance in reducing and oxidizing environments.
ASTM B 861 Grade 9. Very high strength and corrosion resistance..
ASTM B 861 Grade 12. Better heat resistance than pure Titanium. Applications as for Grade 7 and Grade 11.
ASTM B 861 Grade 23. Titanium-6Aluminum-4Vanadium ELI (Extra Low Interstitial) Alloy for surgical implant.
ASTM B 861: Standard Specification for Titanium and Titanium Alloy Seamless Pipe.
ASTM B 338: Standard Specification for Seamless and Welded Titanium and Titanium Alloy Tubes for Condensers and Heat Exchangers.
ASTM B 862: Standard Specification for Titanium and Titanium Alloy Welded Pipe.

Nickel Alloy

ASTM B514, ASTM B517 (UNS N06600, UNS N06603, UNS N06025, and UNS N06045);
ASTM B619 / B619M, ASTM B705 (UNS N06625, N06219 and N08825);
ASTM B725 (UNS N02200/UNS N02201, UNS N04400);
ASTM B775 / B775M, ASTM B464 / B464M (UNS N08020).
B161-03. Standard specification for nickel seamless pipe and tube.
B165-93. Standard specification for nickel-copper alloy (UNS N04400) seamless pipe and tube.
B167-01. Standard specification for nickel-chromium-iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, and N06045) and nickel-chromium-cobalt-molybdenum alloy (UNS N06617) seamless pipe and tube.
B407-01. Standard specification for nickel-iron-chromium alloy seamless pipe and tube.
B444-03. Standard specification for nickel-chromium-molybdenum-columbium alloys (UNS N06625) and nickel-chromium-molybdenum-silicon-alloy (UNS N06219) pipe and tube.
B464-99. Standard specification for welded UNS N08020, UNS N08024, and UNS N08026 alloy pipe.
B514-95: Standard specification for welded nickel-iron-chromium alloy pipe.
B517-03. Standard specification for welded nickel-chromium-iron-alloy (UNS N06600, UNS N06603, UNS N06025, and UNS N06045) pipe.
B619-00. Standard specification for welded nickel and nickel-cobalt alloy pipe.
B622-00. Standard specification for seamless nickel and nickel-cobalt alloy pipe and tube.
B690-02. Standard specification for iron-nickel-chromium-molybdenum alloys (UNS N08366 and UNS N08367) seamless pipe and tube.
B705-00. Standard specification for nickel-alloy (UNS N06625, UNS N06219 and UNS N08825) welded pipe.
B725-93. Standard specification for welded nickel (UNS N02200/UNS N02201) and nickel-copper alloy (UNS N04400) pipe.
B729-00. Standard specification for seamless UNS N08020, UNS N08026, and UNS N08024 nickel-alloy pipe and tube.
B338-02. Standard specification for seamless and welded titanium and titanium-alloy tubes for condensers and heat exchangers.
B444-03. Standard specification for nickel-chromium-molybdenum-columbium alloys (UNS N06625) and nickel-chromium-molybdenum-silicon-alloy (UNS N06219) pipe and tube.
B464-99. Standard specification for welded UNS N08020, UNS N08024, and UNS N08026 alloy pipe.
B514-95: Standard specification for welded nickel-iron-chromium alloy pipe.
B517-03. Standard specification for welded nickel-chromium-iron-alloy (UNS N06600, UNS N06603, UNS N06025, and UNS N06045) pipe.
B619-00. Standard specification for welded nickel and nickel-cobalt alloy pipe.
B705-00. Standard specification for nickel-alloy (UNS N06625, UNS N06219 and UNS N08825) welded pipe.
B725-93. Standard specification for welded nickel (UNS N02200/UNS N02201) and nickel-copper alloy (UNS N04400) pipe.
B338-02. Standard specification for seamless and welded titanium and titanium-alloy tubes for condensers and heat exchangers.

Standard of Steel Pipes

Process plants designed and constructed to the ASME B31.3 code also rely on the standardization of the components used for piping systems and the method of process plant fabrication and construction. There are numerous standards, many of which are interrelated, and they must be referred and adhered to by design engineers and manufacturers in the process industry. These standards cover the following:
• Material: chemical composition, mechanical requirements, heat treatment, etc.
• Dimensions: general dimensions and tolerances.
• Fabrication codes: welding, threading.
Standards covering the preceding were drawn up by the following major engineering bodies:
• American Petroleum Institute (API).
• American Society for Testing and Materials (ASTM).
• American Water Works Association (AWWA).
• American Welding Society (AWS).
• Manufacturers Standardization Society (MSS).
• National Association of Corrosion Engineers (NACE).
• Society of Automotive Engineers (SAE).

Material Standard for Steel Pipes and Tubes

API

API Spec 5B: Specification for Threading, Gauging and Thread Inspection of Casing, Tubing and Line Pipe Threads.
API Spec 5L: Specification for Line Pipe.
ANSI/API Std 1104: Welding of Pipelines and Related Facilities.
ANSI/API RP 1110: Pressure Testing of Liquid Petroleum Pipelines.

ASME

B31.3, Process Piping: This code covers the design of chemical and petroleum plants and refineries processing chemicals and hydrocarbons, water, and steam. It contains rules for the piping typically found in petroleum refineries; chemical, pharmaceutical, textile, paper, semiconductor, and cryogenic plants; and related processing plants and terminals. The code prescribes requirements for materials and components, design, fabrication, assembly, erection, examination, inspection, and testing of piping. This code applies to piping for all fluids, including (1) raw, intermediate, and finished chemicals; (2) petroleum products; (3) gas, steam, air, and water; (4) fluidized solids; (5) refrigerants; and (6) cryogenic fluids. Also included is piping that interconnects pieces or stages within a packaged equipment assembly.
B36.10: This standard covers the standardization of dimensions of welded and seamless wrought steel pipe for high or low temperatures and pressures. The word pipe is used as distinguished from tube to apply to tubular products of dimensions commonly used for pipeline and piping systems. Pipe NPS 12 (DN 300) and smaller have outside diameters numerically larger than corresponding sizes. In contrast, the outside diameters of tubes are numerically identical to the size number for all sizes.
B36.19: This Standard covers the standardization of dimensions of welded and seamless wrought stainless steel pipe for high or low temperatures and pressures. The word pipe is used, as distinguished from tube, to apply to tubular products of dimensions commonly used for pipeline and piping systems. Pipes NPS 12 (DN 300) and smaller have outside diameters numerically larger than their corresponding sizes. In contrast, the outside diameters of tubes are numerically identical to the size number for all sizes. The wall thicknesses for NPS 14 through 22, inclusive (DN 350–550, inclusive), of Schedule 10S; NPS 12 (DN 300) of Schedule 40S; and NPS 10 and 12 (DN 250 and 300) of Schedule 80S are not the same as those of ASME B36.10M. The suffix “S” in the schedule number is used to differentiate B36.19M pipe from B36.10M pipe. ASME B36.10M includes other pipe thicknesses that are also commercially available with stainless steel material.

AWS

AMERICAN WELDING SOCIETY
A3.0: Standard welding terms and definitions, including terms for adhesive bonding, brazing, soldering, thermal cutting, and thermal spraying.
A5.01-93R: Filler metal procurement guidelines.
A5-ALL: Filler metal specifications series plus filler metal procurement guide.

AWWA

AMERICAN WATER WORKS ASSOCIATION
C200-97: Steel water pipe—6 in. (150 mm) and larger.

MSS

MANUFACTURERS STANDARDIZATION SOCIETY
SP-69: Pipe hangers and supports—selection and application.

NACE

NATIONAL ASSOCIATION OF CORROSION ENGINEERS
MR0175: Metals for sulfide stress cracking and stress corrosion cracking resistance in sour oilfield environments.
RP0170: Protection of austenitic stainless steels and other austenitic alloys from polythionic acid stress corrosion cracking during shutdown of refinery equipment.
RP0472: Methods and controls to prevent in-service environmental cracking of carbon steel weldments in corrosive petroleum refining environments.

SAE

SOCIETY OF AUTOMOTIVE ENGINEERS SAE
J 518: Hydraulic flanged tube, pipe, and hose connections, four-bolt split flange type.

ASTM

American Society of Testing and Materials
The American Society of Testing and Materials specifications cover materials for many industries, and they are not restricted to the process sector and associated industries. Therefore, many ASTM specifications are not relevant to this book and will never be referred to by the piping engineer.
We included a number of the most commonly used ASTM specifications in the Materials page of the products.

ASME 36.10, ASME 36.19 are the key specifications covering the standardization of dimensions of welded and seamless wrought steel pipe. ASME B16.25 covers the preparation of butt weld connections between pipes and ASME B16.49 covers the marking details.

ASME 36.10

This standard covers the standardization of dimensions of welded and seamless wrought steel pipe for high or low temperatures and pressures. Pipe NPS 12 (DN 300) and smaller have outside diameters numerically larger than corresponding sizes. In contrast, the outside diameters of tubes are numerically identical to the size number for all sizes.
The size of all pipe is identified by the nominal pipe size. The manufacture of pipe NPS ⅛ (DN 6) to NPS 12 (DN 300), inclusive, is based on a standardized outside diameter (O.D.). This O.D. was originally selected so that pipe with a standard O.D. and having a wall thickness that was typical of the period would have an inside diameter (I.D.) approximately equal to the nominal size. Although there is no such relation between the existing standard thickness – O.D. and nominal size – these nominal sizes and standard O.D.s continue in use as “standard.” The manufacture of pipe NPS 14 (DN 350) and larger proceeds on the basis of an O.D. corresponding to the nominal size.

ASME 36.19

This Standard covers the standardization of dimensions of welded and seamless wrought stainless steel pipe for high or low temperatures and pressures.
Pipes NPS 12 (DN 300) and smaller have outside diameters numerically larger than their corresponding sizes. In contrast, the outside diameters of tubes are numerically identical to the size number for all sizes. The wall thicknesses for NPS 14 through 22, inclusive (DN 350-550, inclusive), of Schedule 10S; NPS 12 (DN 300) of Schedule 40S; and NPS 10 and 12 (DN 250 and 300) of Schedule 80S are not the same as those of ASME B36.10M. The suffix S in the schedule number is used to differentiate B36.19M pipe from B36.10M pipe. ASME B36.10M includes other pipe thicknesses that are also commercially available with stainless steel material.

API 5L

ANSI / API 5L specifies the manufacture of two product levels (PSL1 and PSL2) of seamless and welded steel pipe for the use of a pipeline in the transportation of petroleum and natural gas. For material use in a sour service application, refer to Annex H; for offshore service application, refer to Annex J of API 5L 45th Edition.
Grades covered by this specification are A25, A, B and “X” Grades X42, X46, X52, X56, X60, X65, X70, and X80. The two digit number following the “X” indicates the Minimum Yield Strength (in 000’s psi) of pipe produced to this grade.

Manufacturing Process of Steel Pipes

Steel pipe can be broadly categorized according to manufacturing method as seamless pipe made by hot rolling or hot extrusion, and welded pipe and butt-welded pipe made by bending and welding sheets or plates.

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When seamless pipe is made by rolling, the rolling method involves piercing the material while it is being rolled, and is suitable for mass production. The figure shows the manufacturing process used in the Mannesmann plug mill, which is a typical rolling process. The Mannesmann-type piercer reduces the material by rolls that are inclined obliquely to each other. When the round billet is rotated while being compressed in the diametric direction, the central part of the billet becomes loose, which makes it easy to pierce a hole through the center. This is called the Mannesmann effect. The pierced portion is expanded by the elongator, and the wall thickness is then thinned and elongated by the plug mill. The internal and external surfaces are smoothed by the reeler, and the final dimensional adjustments are made by the sizer.
The hot-extrusion method involves working in the compressive-stress field. Therefore, it is characteristic of this method that high-alloy steel pipe of low deformability can be produced, as well as heavy-wall and large-diameter pipes.
Seamless pipe has outstanding homogeneity in the circumferential direction and is thus highly resistant to internal pressure and torsion. Taking advantage of this feature, seamless pipe is widely used for drilling and pumping petroleum and natural gas.
Welded pipe is divided into electric-resistance welded (denoted ERW hereinafter) pipe, spiral pipe, and UO pipe according to the forming and welding method. ERW pipe and butt-welded pipe are produced by continuously forming a hot-rolled coil into a tubular shape by forming mills. ERW pipe is produced by cold forming, and the seam is welded by electric-resistance welding. This type of steel pipe is used in large quantities as line pipe for transporting petroleum and gas. Butt-welded pipe is produced by hot forming after the whole material has been heated, and seams are then butt welded. This type of pipe is hot-dip galvanized and used for carrying water and gas.
The outer diameter of ERW pipe and butt-welded pipe is determined by the width of the material coil. However, as shown in the figure, spiral pipe is made by forming the coil into a spiral shape, which makes it possible to obtain a large outer diameter regardless of the width of the material. UO pipe is usually large in diameter and produced one piece at a time by forming plates. The plate is first pressed into a U shape by the U-press, and then into an O shape by the O-press.
Because relatively thick material is used for making spiral and UO pipes, submerged arc welding is used for joining. The principal application of spiral pipe is pipe piles. UO pipe, as mentioned above, is mainly used as line pipe for transporting petroleum and natural gas in large quantity over long distances.

Manufacturing Process of Seamless Pipes

Seamless pipe is Strongest amongst all pipes type as it has a Homogeneous structure throughout pipe length.

Seamless pipes are manufactured in a verity of size and schedule. However, there is a Restriction on the manufacturing of large diameter pipe. Seamless pipes are widely used in the manufacturing of pipe fittings such as bends, elbows, and tees.
Various Manufacturing process are explained in detail;
• Mandrel Mill Process
• Mannesmann Plug Mill Pipe
• Forged Seamless Pipe
• Extrusion Processes
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The seamless pipes manufacturing process involves the following steps:
• Transformation of raw materials into steel bars (Electric arc furnace, ladle furnace, vacuum degassing and continuous casting processes)
• Transformation of steel bars into mother pipe, which is manufactured in different types of rolling mills
Each product is manufactured in accordance with customer specifications, including heat treatment for more demanding applications. The pipes are threaded and undergo non-destructive testing before delivery to the customer.
We can also offer cold-drawing for pipes with the diameter and wall thickness required for use in boilers, superheaters, condensers, heat exchangers, automobile production and several other industrial applications.

Seamless Pipes Manufacturing

Mandrel Mill Process
In Mandrel Mill pipe manufacturing process, steel billet is heated to high temperature in the rotary furnace. A cylindrical hollow, which is also known as mother hollow, is produced with the help of a rotary piercer and set of roller arrangement that keeps the piercer at the center of the billet. Outside diameter of piercer is approximately that of the inside diameter of the finished pipe. With the help, secondary roller arrangement outside diameter and thickness are achieved.

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Mannesmann Plug Mill Pipe
In the Plug Mill Process, a solid round (billet) is used. It is uniformly heated in the rotary hearth heating furnace and then pierced by a Mannesmann piercer. The pierced billet or hollow shell is roll reduced in outside diameter and wall thickness. The rolled pipe simultaneously burnished inside and outside by a reeling machine. The reeled pipe is then sized by a sizing mill to the specified dimensions. From this step the pipe goes through the straightener. This process completes the hot working of the pipe. The pipe (referred to as a mother pipe) after finishing and inspection, becomes a finished product.

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Forged Seamless Pipe
In a Forging pipe manufacturing process, a heated billet is placed in forging die that has a diameter slightly larger than the finished pipe. A hydraulic press of forging hammer with matching inside diameter is used to create cylindrical forging. Once this forging is done pipe is machined to achieve final dimension. Forging pipe manufacturing process is used to manufacture large diameter seamless pipe that cannot be manufactured using traditional methods. Forged pipes are normally used for the steam header.

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Extrusion Processes
In an extrusion pipe manufacturing a heated billet is placed inside the die. A hydraulic ram pushes the billet against the piercing mandrel, material flows from the cylindrical cavity between die and mandrel. This action produces the pipe from the billet. Sometimes pipe manufactured produce pipe with a high thickness which is known as mother hollow. Many secondary pipes manufactured used this mother hollow to produce pipe with different dimensions.

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Manufacturing Process of Welded Pipes

Welded Pipes are manufactured from Plate or continues Coil or strips. To manufacture welded pipe, first plate or coil is rolled in the circular section with the help of plate bending machine or by a roller in the case of continues process. Once the circular section is rolled from the plate, the pipe can be welded with or without filler material. Welded pipe can be manufactured in large size without any upper restriction. Welded pipe with filler material can be used in the manufacturing of long radius bends and elbow. Welded pipes are cheaper with compared to the seamless pipe and also Weak due to the weld.
There are different welding methods used to weld the pipe.
• ERW- Electric Resistance Welding
• EFW- Electric Fusion Welding
• HFW- High-frequency welding
• SAW- Submerged Arc Welding (Long seam & Spiral Seam)
Less thickness pipe, mainly ERW / EFW or HFW welded pipe are formed by continues rolling method. In this method, a flat metal strip from the strip coil is feed into the series of roller assembled in line. These rollers gradually form the strip in the circular section. At the end of rolling assembly, this pipe is continuously welded by welding machine.
ERW/EFW and HFW are welding methods in which pipe is welded without adding filler material. However, EFW welding method can be used with filler material also.
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Welded Pipes Manufacturing Process

ERW
In ERW welding, two electrodes, usually made from copper, are used to apply pressure and current. The electrodes are disc shaped and rotate as the material passes between them. This allows the electrodes to stay in constant contact with the material to make long continuous welds.
A welding transformer supplies low voltage, high current AC power. The joint of the pipe has high electrical resistance relative to the rest of the circuit and is heated to its melting point by the current. The semi-molten surfaces are pressed together with a force that creates a fusion bond, resulting in a uniformly welded structure.

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EFW
EFW steel pipe is formed by rolling plate and welding the seam. The weld flash can be removed from the outside or inside surfaces using a scarfing blade. The weld zone can also be heat treated to make the seam less visible. Welded pipe often has tighter dimensional tolerances than seamless, and can be cheaper if manufactured in the same quantities. It is mainly used for welding dissimilar steel welding sheet or which high power density, metal weldment can rapidly heated to high temperatures, which can melt any refractory metals and alloys. Deep penetration welding fast, heat-affected zone is extremely small, so small performance impact on the joints, the joint almost no distortion. But it has a requirement on a special welding room because welding using X-rays.

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HFW
High frequency welding (HFW) steel pipe is that ERW pipe produced with a welding current frequency equal to or greater than 70 kHZ. Through high-frequency current welding resistance, the heat generated in the contact objects, so the objected surface are heated to the plastic state, then with or without forging to achieve a combination of steels. HFW is a solid resistance heat energy. The high frequency current pass through the metal conductor, will produce two peculiar effects, skin effect and proximity effect. And HFW process is to use the skin effect to concentrate on steel object surface, use proximity effects to control the position and the power of the high-frequency electric current flow path. Since the speed is very high, the contacted plate edge could be heated and melted in short time, then extruded through docking process.
In the welding process, HFW steel pipes do not need to add filling meta. So it has fast welding speed and high efficiency in production. HFW pipe is widely used in the fields of oil and gas transportation, oil well pipeline, building structure and various kinds of mechanical pipe. However, HFW steel pipe quality is affected by many factors, such as raw material and process. And the production quality control become difficult. So the yield and welding process still need to be improved continuously.

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SAW
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LSAW Pipe (Longitudinal Submerged Arc-Welding Pipe), is taking the steel plate as raw material, mold it by the molding machine, then do double-sided submerged arc welding. Through this process the LSAW steel pipe will get excellent ductility, weld toughness, uniformity, plasticity and great sealing.
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SSAW Pipe (Spiral Submerged Arc-Welding Pipe), also called HSAW pipe, welding line shape like a helix. It is using the same welding technology of Submerged Arc-Welding with LSAW pipe. Differently SSAW pipe is spiral welded where the LSAW is longitudinally welded. Manufacturing process is rolling the steel strip, to make the rolling direction have an angle with the direction of the pipe center, forming and welding, so the welding seam is in a spiral line.
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Heat Treatment Method of Carbon and Alloy Steel Pipe

Heat treatment methods for carbon and alloy steel pipe include 4 mainly types:
Normalizing, Annealing, Quenching and Tempering.
It will improve steel material mechanical properties, uniform chemical composition, and machinability.
Heat treatment for steel metal materials can be divided into integral heat treatment, surface heat treatment and chemical heat treatment. Steel pipe generally adopts the integral heat treatment.
The performance of steel material mainly refers on mechanical properties, physical properties, and process performance. Heat treatment will bring different metallurgical structure and corresponding performance for the steel pipe, so could be better applied in different industrial or the oil and gas services.
There are two methods to improve the properties of steel material. One method is to adjust the chemical composition, named alloying method. The other method is heat treatment. In the field of modern industrial technology, heat treatment improve steel pipe performance at dominate position.

Heat treatment purposes

1. Heating.
The steel material could be heated below the critical point or above critical point. The former heating way can stabilize structure and eliminated the residual stress. The latter way can make material austenitizing.
Austenitizing is to heat steel metal over its critical temperature long time enough, so it could be transformed. If a quenching followed after Austeniting, then the material will be harden. Quenching will take fast enough to transform austenite into martensite. Once reached austenitizing temperature, suitable microstructure and full hardness, the steel pipe material will be attained in further heat treatment processes.
2. Heat preservation.
The purpose of heat preservation is to uniform the heating temperature of steel material, then it will get a reasonable heating organization.
3. Cooling
The cooling process is the key process in heat treatment, it determines mechanical properties of steel pipe after cooling process.
Four main heat treatment methods in carbon and alloy steel pipe industry
The heat treatment processes for steel pipe includes normalizing, annealing, tempering, quenching and other process.

Normalizing

Heating the steel pipe above the critical temperature, and cooled in the air.
Through normalizing, the steel material stress could be relieved, improves ductility and toughness for the cold working process. Normalizing usually applied for the carbon and low alloy steel pipe material. It will produce different metal structure, pearlite, bainite, some martensite. Which brings harder and stronger steel material, and less ductility than full annealing material.

Annealing

Heating the material to above its critical temperature long enough until microstructure transform to austenite. Then slow cooled in the furnace, get maximum transformation of ferrite and pearlite.
Annealing will eliminate defects, uniform the chemical composition and fine grains. This process usually applied for the high carbon, low alloy and alloy steel pipe need to reduce their hardness and strength, refine the crystal structure, improve the plasticity, ductility, toughness and machinablity.

Quenching

Heating the steel pipe material to critical temperature until microstructure transformation is done, cooling it in a rapid rate.
Quenching purpose is to produce the thermal stress and tissue stress. It can eliminate and improve through the tempering. The combination of quenching and tempering can make the comprehensive performance improved.

Tempering

Heating the steel material to a precise temperature below the critical point, and often done in the air, vacuum or the inert atmospheres. There are low temperature tempering 205 to 595°F (400 to 1105°F), medium temperature and high temperature tempering (to 700℃ 1300°F).
The purpose of tempering is to increase the toughness of steel and alloy steel pipe. Before tempering, these steel is very hard but too brittle for the most application. After process can improve the plasticity and toughness of steel pipe, reduce or eliminate the residual stress and stabilize the steel pipe’s size. Brings good comprehensive mechanical properties, so that it does not change in service.

Solution treatment for alloy-based steel pipe material

Heating an alloy to a proper temperature, preserve it at this temperature long enough to cause or more constituents to change into a solid solution, then cooling it at rapid rate to hold these constituents in solution.
There are several of cast and wrought nickel-based alloys that can achieve different required performances through solution treatment or by precipitation age hardening. Characteristics as room temperature and elevated temperature mechanical strength, corrosion resistance and oxidation resistance will be significantly enhanced by this heat treatment. Many nickel-based alloys develop their desired properties solely through the solution treatment, like Hastelloy and nickel alloy steel pipe.
During solution treatment, the carbide and various alloying elements are dissolved uniformly in the austenite. Cooling rapidly will make carbon and alloy elements too late to precipitate, and obtain the heat treatment process of single austenite tissue. The solution treatment can uniform internal structure and chemical compostion. It can also restore the corrosion resistance for Hastelloy and nickel alloy steel pipe.

Inspection of steel pipes

As a technically complex deep-processed metal product, the quality of the metal material determines the quality of the steel pipe, which requires good physical and chemical properties of the metal material, uniform material, and high purity of the composition.
In the actual production and use process, if there are defects inside the steel pipe will leave a hidden danger to the quality and safety of the project, which will cause serious accidents, so the quality of its star testing has also been widely concerned.
At present, the main detection methods of steel pipe eddy current method, ultrasonic method, leakage method, these detection methods have their own advantages and disadvantages, the following three detection methods to do a comparative analysis:.

Eddy current detection method

Eddy current detection is the use of electromagnetic induction principle, when the detection line containing alternating current is relatively close to the conductive test piece, due to electromagnetic induction within the test piece will induce eddy currents.
Eddy current size, phase and form of flow will be affected by the conductivity of the test piece, shape, etc., the eddy current generated by the reaction of the magnetic field and the impedance of the detection coil changes.
Therefore, by measuring the change in the impedance of the detection coil, you can determine the performance or state of the tube and pipe under test, so as to achieve the purpose of nondestructive testing of steel pipe defects.
Commonly used eddy current inspection probe there are two types: point probe and through the probe.
The main advantage of eddy current detection is no coupling agent, non-contact detection, detection speed, high detection sensitivity; its main disadvantage is affected by the skin effect, can only check the surface of thin or thick specimens and near-surface parts, can not effectively detect defects in the wall of the steel pipe.

Ultrasonic testing method

Ultrasonic testing method detection accuracy is relatively high, and easy to operate.
However, the ultrasonic ferry detection method is point detection, while the need for coupling agent, detection efficiency is low, to achieve rapid detection is more difficult.
In recent years, in order to adapt to the rapid detection requirements, people are constantly studying the coupling technology of ultrasound, such as air coupling, electromagnetic ultrasound, laser ultrasound and direct magnetostrictive coupling and other technologies.
Germany uses water shower ultrasonic coupling technology to achieve comprehensive detection of industrial pipeline wall thickness and longitudinal cracks, it can meet the needs of a variety of defects from multiple flaw detection surface at the same time comprehensive detection, well can achieve automatic scanning, digital control and data acquisition, thereby improving the speed of flaw detection and the reliability of ultrasonic flaw detection.
There are many methods of ultrasonic flaw detection, commonly used to make the general pulse reflection method. Due to defects within the object, the object material internal discontinuity, when the pulse propagates to the discontinuity, due to the discontinuity of the acoustic impedance of the discontinuity, and the pulse will be in the two acoustic impedance inconsistency of the reflection phenomenon, while the ultrasonic reflection back to the size and direction of the energy and the intersection of the orientation of the size of the interface.

Leakage detection method

Leakage magnetic method of detection of the basic principle is that
The material under test is magnetized under the action of the applied magnetic field, when there is no defect in the material, most of the magnetic lines of force through the material under test, when the magnetic lines of force are uniformly distributed.
When there is a defect in the material, the magnetic lines of force dome bend, and part of the magnetic lines of force leak out of the surface of the material, forming a leakage field.
Using magnetic sensitive elements to detect the leakage magnetic field escaping from the surface of the magnetized material, you can determine whether the defect exists.
Defects of the same size, located on the surface and below the surface form a different leakage field.
The leakage field generated by a defect on the surface is large; when the defect is under the surface, the leakage field formed will be significantly smaller.
Leakage flux method is applicable to all kinds of ferromagnetic materials, and can inspect defects such as cracks and corrosion, and can discern the location of defects.
The main characteristics of the leakage magnetic detection method are: the surface of ferromagnetic materials, near the surface, internal cracks and corrosion can be obtained satisfactory detection results.
Probe device structure is simple, easy to implement, low cost and easy to operate; not affected by the contamination of the surface of the material under test, when the detection of the material under test surface cleanliness requirements are not high.
Able to achieve high detection speed, can achieve fully automated detection, very suitable for quality inspection and production process control on the assembly line.
Therefore, in today’s many steel pipe inspection methods, leakage detection methods are most widely used.

The practical application of non-destructive testing methods for steel pipe

Eddy current steel pipe flaw detection

By the basic characteristics of eddy current can be seen, eddy current density is mainly distributed near the surface of conductive materials.
Therefore, the measurement of steel pipe is the presence of surface defects, the fuller the use of eddy current effect.
So eddy current detection is suitable for the detection of conductive steel pipe surface defects or near-surface defects, when the sensitivity is higher than the leakage detection.
For internal defects, eddy current detection due to the existence of the “skin effect”, eddy current density in the conductive conductor is decaying according to the negative exponential law, and with the increase in frequency, electrical and magnetic permeability and penetration depth decreases, the detection sensitivity is reduced.
Eddy current detection can generally only detect single-sided surface defects (inner or outer surface) of seamless steel tubes.
Leakage detection can detect internal and external surface defects of seamless steel pipe when asked, and also has a certain sensitivity for internal defects, as opposed to leakage detection which can detect internal and external surface defects of seamless steel pipe when asked, and also has a certain sensitivity for internal defects.

Ultrasonic detection of steel pipe wall thickness

Steel pipe wall thickness detection is often used in ultrasonic testing of resonance and pulse reflection of the two ways to engage in the industry.
The principle of resonant wall thickness detection is the use of frequency in a certain range due to changes in the sine wave electrical signal to stimulate the chip, then the piezoelectric chip will produce a continuous change in frequency of sound waves, and point to the interior of the test piece, resonance principle, if the thickness of the test piece is an integer multiple of half wavelength, then the test piece will form a standing wave, thus producing resonance.
Then based on the relationship between the wavelength and the wall thickness of the formula to find out the wall thickness.
But the general corrosion of steel pipe thickness detection can not use this method, because the resonant thickness measurement requires the upper and lower surface of the test piece flat, corrosive steel pipe surface rough divination, the more only detection.
The principle of pulse reflection thickness measurement is the use of thickness and speed of sound and the relationship between the propagation time of ultrasonic waves in the specimen to determine the wall thickness.

Leakage magnetic detection of steel pipe defects

Defects in the end of steel pipe, defects in the howl area at the end of oil pipe and defects in the threaded area of drill pipe mainly include cracks, corrosion pits, cavities and bias wear due to stress concentration.
The AC magnetic leakage probe was used to detect the defects in the blind area of the steel pipe end, with a sensor probe length of 10 mm and a minimum theoretical detection blind area of 5 mm.
The main purpose of using AC magnetic leakage to detect the threaded area of the drill pipe is to solve the distance of the Hall element from the root of the thread, and to form a strong magnetization path.
The detection of the external thread area of the oil pipe and the end of the steel pipe is mainly through the external scanning method of internal magnetization of the end to detect its transverse injury, which basically eliminates the blind area of detection due to the use of the I-beam magnetizer.
The high sensitivity of the two methods improves the defect recognition capability of the instrument.
Leakage magnetic detection can not only detect internal and external surface and subcutaneous defects, and without detection can be informed from the relationship between the established electrical signal amplitude and defect parameters, whether the defect depth and length and other characteristic dimensions reach the set rejection level. High detection capability and fast detection speed.
A single non-destructive testing method can only detect some of the defects in the steel pipe, and because the speed of detection is too different, ultrasonic and eddy current detection and difficult to simply combine together, while the measurement of the size of the steel pipe appearance and identification of the material can only be completed by hand.
This situation does not adapt to the needs of modern mass production, can not intuitively display defects so that its application has caused certain limitations, not to mention the production process to play the role of quality star control and supervision had.
Therefore, the future development direction should be to the strong detection ability, fast detection, signal processing, image forming and other directions to make its technology more mature.

Installation of steel pipes

1. According to the caliber and the specific situation of the pipe, choose the suitable connection method

  • Welding: According to the progress of the site at the appropriate time into the installation. Pre-fix the bracket, according to the actual size, draw a good sketch, prefabricated pipes, as far as possible to reduce the pipe fittings on the pipe, weld the dead end. The pipe is pre-straightened, the installation interruption should be closed open, the design requires the addition of casing in the installation process, according to the requirements of the design and equipment, the interface is reserved, on the good plug, ready for the next step in the process of test pressure work.
  • Threaded connection: The processing of pipe threads is set by a wire sleeve machine. 1/2″-3/4″ pipe can be manually sleeve, after the wire buckle is set, the orifice should be cleaned and kept smooth, and the thread breakage should not exceed 10% of the total number of threads. The connection should be firm, the root is not exposed to the phenomenon of oil hemp, the root exposed thread should not be more than 2-3 buckles, the exposed part of the thread is good corrosion protection.
  • Flange connection: pipeline and valves and other connections are required to use flange connection. Flange can be divided into flat welding flange, butt welding flange, etc., flange selection of finished products. Flange and pipe centerline perpendicular, pipe mouth shall not protrude from the flange sealing surface. Fastening flange bolts should be brushed with lubricant before use, to be symmetrical cross, in 2-3 times tightening, screw exposed length of not more than 1/2 screw diameter, the nut should be on the same side, the flange liner shall not protrude into the pipe, the middle of the flange shall not have a slant pad and more than two pads.

2. The anti-corrosion: bright steel pipe outside the silver powder brush two, dark steel pipe brush asphalt two.
3. Before the installation of pipeline laying should be cleaned up inside the dirt, strictly prevent welding slag and other garbage fall into the pipe, the installed pipeline, shall be wrapped and sealed.
4. The construction is completed, the whole system should be hydrostatic pressure test. The pressure of the living water supply part is: 0.6mpa, and the pressure drop is not more than 20kpa in five minutes, which is qualified.

Storage management of steel pipes

Choose suitable site and warehouse

  • 1) The site or warehouse for steel storage should be chosen in a clean, well-drained place, away from mines and factories that produce harmful gases or dust. Weeds and all debris should be removed from the site to keep the steel clean.
  • 2) In the warehouse should not be stacked with acid, alkali, salt, cement and other materials that are aggressive to steel. Different varieties of steel should be stacked separately to prevent confusion and contact corrosion.
  • 3) Large sections, rails, thick steel plates, large diameter steel pipes, forgings, etc. can be stacked in the open.
  • 4) Small and medium-sized sections, coils, bars, medium-diameter steel pipes, steel wire and wire rope, etc., can be stored in a well-ventilated shed, but must be thatched under the mat.
  • 5) Some small steel, thin steel plate, steel strip, silicon steel sheet, small-diameter or thin-walled steel pipe, various cold-rolled and cold-drawn steel and metal products with high price and easy corrosion can be stored in the warehouse.
  • 6) The storage room should be selected according to the geographical conditions, generally using ordinary closed storage room, that is, a roof with walls, doors and windows tightly, with ventilation devices.
  • 7) The warehouse should be ventilated on sunny days and closed on rainy days to prevent moisture, so as to maintain a suitable storage environment.

Reasonable stacking, first-in-first-out

  • 1) The principle of stacking is to ensure the safety and stability of palletizing, and to palletize according to varieties and specifications, and to palletize different varieties of materials separately to prevent confusion and mutual corrosion.
  • 2) It is forbidden to store items that have corrosive effect on steel near the pallets.
  • 3) The bottom of the pallets should be high, firm and flat to prevent the materials from getting wet or deformed.
  • 4) The same material should be stacked according to the order of storage, so that the principle of first-in-first-out can be implemented.
  • 5)The steel sections stacked in the open air must have wooden mats or stones underneath, and the surface of the pile should be slightly inclined to facilitate drainage, and the material should be placed straight to prevent bending and deformation.
  • 6) The height of stacking should not exceed 1.2m for manual work, 1.5m for mechanical work and 2.5m for stacking width.
  • 7) There should be a certain channel between the stack and the pile, the inspection channel is generally 0.5m, the access channel depends on the size of the material and transport machinery, generally 1.5-2.0m.
  • 8) The bottom of the pile should be padded, if the warehouse is the cement ground in the sunrise, it can be padded 0.lm; if it is the mud ground, it should be padded 0.2-0.5m. If it is the open field, the cement ground should be padded 0.3-0.5m, and the sand and mud surface should be padded 0.5-0.7m.
  • 9) Open-air stacking of angles and channels should be placed on top, that is, the mouth down, I-beams should be placed upright, the groove side of the steel can not face up, in order to avoid water rusting.

Protect the protective layer of the material box
This is an important measure to prevent rusting of the material, which should be protected during transportation, loading and unloading, and should not be damaged to extend the storage period of the material.
Keep the warehouse clean and strengthen material maintenance

  • 1) Before the material is put into the warehouse, attention should be paid to prevent rain or mixed with impurities, and the material that has been drenched or stained should be wiped clean by different methods according to its nature, such as steel wire brush for high hardness, cloth and cotton for low hardness.
  • 2) The material should be checked frequently after the storage, if there is rust and corrosion, the rust and corrosion layer should be removed.
  • 3) After the surface of general steel is cleaned, there is no need to apply oil, but for high quality steel, alloy thin steel plate, thin-walled pipe, alloy steel pipe, etc., after rust removal, its inner and outer surface should be coated with anti-rust oil before storage.
  • 4) For steel with serious rust, it is not suitable for long-term storage after rust removal and should be used as soon as possible.

Steel appearance quality inspection
When inspecting the appearance quality of steel before storage, the following matters must be noted.

  • 1) When observing the surface of hot rolled steel with the naked eye, no cracks, folds, scars, layering and inclusions are allowed. Indentation and local projections, depressions, pockmarks are allowed, but their height or depth shall not be greater than the relevant technical standards. Local defects are allowed to clear, but no horizontal removal, removal depth from the actual size of the size of the steel shall not exceed the negative deviation value allowed.
  • 2) When observing the surface of cold drawn steel with the naked eye, the surface should be clean, smooth, bright or lusterless, without cracks, scars, inclusions, hairlines, folding and oxide skin. Allowed depth is not greater than the nominal size deviation from the actual size of the individual small scratches, cracks, black spots, concave surface, pockmarks, etc..
  • 3) The appearance of the steel section should be smooth and neat, its roundness, side width, height, thickness, length, twist, slope, scoop curvature, wave bend and unevenness, shall not exceed the deviation specified in the relevant standards.
  • 4) Steel sections should be straightened, steel plates should be leveled, and the side ends must be cut into right angles. Rail in addition to the above provisions, rail ends and bolt hole surface, there shall be no shrinkage, delamination and cracks, both ends should be milled flat.
  • 5) Steel pipe wall thickness, surface roughness, roundness and unevenness, should be in line with technical standards. Steel pipe with thread, galvanized steel pipe and geological pipe joint threads should be oiled, and there should be a protective ring.
  • 6) galvanized steel and galvanized steel pipe galvanized layer is not allowed to have cracks, layer, leakage of plating and other defects.

Main Applications of Pipes & Tubes 

● Oil & gas downstream & upstream activities
● Pipelines
● Refinery, chemical and petrochemical plant
● Mineral industries
● Aerospace
● Power generation
● Mechanical construction applications

How to get a cost-effective steel pipe solution?

Steel pipe purchase points

1. According to the actual needs of the project.
According to the different types, materials and quantities of steel pipes actually needed in the project to make the purchase.
2. According to the price of steel pipe.
According to the budget to buy and sell, compared to three, buy better quality and more reasonable price of steel pipe, usually seamless steel pipe is more expensive than seamed steel pipe.
3. According to the quality.
Check the appearance of the steel pipe, the inner wall is smooth and flat, there is no dent, a batch of products are fully marked.

Steel pipe buying tips

  • 1. Watch the color of the outer surface and the inner wall of the tube is bright and smooth, whether the thickness is uniform, or rough.
  • 2. Choose the one with basically uniform color, smooth and flat inner and outer walls, without bubbles, dents, impurities and other defects affecting surface performance.
  • 3. To see whether the product identification is complete, the steel pipe should have the production plant name or trademark, production date, product name, specification size, implementation of the standard number, etc., the steel pipe should have the product name, nominal outside diameter, pipe series S, etc., the handwriting should be clear, and check whether the identification and the actual match.
  • 4. Steel pipe specifications should be listed in the import and export trade contract. Generally should include the standard grade (type code ), the nominal diameter of the steel, nominal weight (mass), the specified length and the above indicators of the tolerance value and other items.

Source: China Pipes Solutions Supplier – Yaang Pipe Industry (www.epowermetals.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at [email protected]

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