China piping solution supplier: | Email: sales@epowermetals.comTel: +8618267732328

What are flanges solutions?

What are pipe flanges?

Pipe flanges are discs, collars or rings that are attached to pipes for the purpose of providing greater strength support, plugging pipes or enabling connections for more items. They are typically welded or screwed to the end of the pipe and bolted together. A gasket is inserted between two mating flanges to provide a tighter seal. These flanges can be custom made to customer supplied dimensions or manufactured to published specifications. Several organizations and associations have published specifications that provide dimensional information and pressure specifications at different temperatures.

Types of flanges

20231010081402 35862 - What are flanges solutions?

The structure of flanges is relatively simple, consisting of upper and lower flange pieces, intermediate gaskets and several bolts and nuts. From the definition of flanges, we can know that there are many types of flanges and need to distinguish their classification from different dimensions. For example, the flange can be divided into integral flange, flat welding flange, butt welding flange, loose-fitting flange and threaded flange according to the connection method, which are also common flanges.

948c83cd47224d9f858d7fc84f898d1f - What are flanges solutions?

Integral flange is generally used in the larger pressure pipeline, is the flange connection method, and all have a long neck, more than once the whole casting molding, and the materials used are generally carbon steel, stainless steel, etc..
Flat welding flange, also known as tower welding flange, when it is connected to the vessel or pipeline for welding, this flat welding flange has the characteristics of easy assembly, cheap, mainly used for pressure and vibration relatively small pipeline.
Butt-welding flange is also known as high neck flange. The biggest difference between butt-welding flange and other flanges is that it has a protruding high neck. The wall thickness of the protruding high neck will gradually be the same as the thickness and diameter of the highly buttressed pipe wall, which will increase the strength of the flange. Butt-welding flanges are mainly used in places with large environmental changes, such as high temperature, high pressure and low temperature pipelines.
Loose set flange is also called live set flange, mostly used for some non-ferrous metals and stainless steel pipeline, the connection is also achieved by welding, because it can be rotated, easy to align with the bolt hole, so it is mostly used for large diameter pipelines that often need to be disassembled and often need to disassemble the connection, but loose set flange low pressure resistance, can only be used for low pressure pipeline connection.
Threaded flanges have threads inside the flange, which requires the internal connection of the pipe also has external threads to achieve the connection. It is a non-welded flange, so it has the advantage of easy installation and disassembly compared with other welded flanges. In the use of extremely high or low temperature environment is not suitable for the use of threaded flanges, because the threads are subject to thermal expansion and contraction of the pipe leakage.

Anchor Flanges

An anchor flange is a device installed on a pipeline to combat axial movement. Resembling a collar, once it is attached to a pipe, the anchor flange is commonly anchored into a concrete foundation. Typically placed onto a section of pipeline as it makes a turn or is at a bridge crossing, the anchor flange is used to prevent the pipeline from moving.
One of the common traits of a metal pipeline is its inherent movement caused by the flow of liquid through the pipe, as well as from the expansion and contraction caused by temperature changes. When a pipeline makes a sharp turn, the flow of liquid inside of the pipeline attempts to push the pipe in the direction of the flow. By placing an anchor flange on the pipeline and securing it into position by locking it in a concrete pillar buried deep into the ground, the forces pushing against the pipe are displaced into the earth.

Blind Flanges

blind 1 - What are flanges solutions?

A Blind Flange is a Flange which has no bore hole and consequently it is used to close the end of a piping system. The Blind Flange is sometimes machined to accept a pipe of the nominal size to which reduction is being made. The Blind Flange reduction can be either threaded or welded. A Blind Flange also allows easy access to a line once it has been sealed.

Blind Flanges are manufactured without a bore and used to blank off the ends of piping, Valves and pressure vessel openings.
From the standpoint of internal pressure and bolt loading, blind flanges, particularly in the larger sizes, are the most highly stressed flange types.
However, most of these stresses are bending types near the center, and since there is no standard inside diameter, these flanges are suitable for higher pressure temperature applications.

Expander Flanges

Expander Flange is a special purpose industrial pipe flange designed to provide expanded connections to adjoining pipe or fittings. Expander Flange reduces the cost of Reducer & two spool flanges.
Expander Flanges are manufactured to specific requirements in Oil & Gas, Chemical Process Industries, Paper & Pulp, Offshore & OnShore Platforms, etc.
Expander Flange can be made to available in Carbon Steel, Low Temperature Alloy Steel, Stainless Steel, Duplex Steel, Nickel Alloys, Titanium, Tantalum & Non Ferrous Alloys.

High Hub Flanges

The high hub blind flange is used to close ends of piping systems. It is a kind of round plate with no center hold but with all the proper bolt holes. This high hub blind flange is available in various sizes and materials and is used to provide positive closer on the ends of pipes, valves or equipment nozzles. This flange helps in easy access to a line once it has been sealed. The high hub blind flange is sometimes custom made or machined to accept a nominal sized pipe to which reduction is being made. This reduction can be a threaded reduction or welded reduction.

Lap Joint Flanges

A Lap Joint Flange is usually used in conjunction with Lap Joint Stubs. Lap Joint Flanges in carbon or low alloy steel piping systems are best used when frequent dismantling for inspection and cleaning is required. The use of Lap Joint Flanges at points where severe bending stress occurs should be avoided.

Long Weld Neck Flanges

long welding neck 1 - What are flanges solutions?

A Integral Flange which is also called Long weld neck flange (LWN flange), is used for high pressure situations, integral hub weld neck flanges are used and for very high pressure cases Long Welding Neck flanges are preferred. In this case, the weld are far from the ring to avoid bending stresses and weld stress being combined.

Long Weld Necks are shaped like a slip on flange with a piece of pipe already attached but are formed and machined in a one-piece construction. As the name suggests, Long neck flange has long neck than regular weld neck flange. Other than neck, all the dimensions are same as the regular flanges. You can see the difference in the image. It is used as a nozzle in the pressure vessel and heat exchanger. you can see that Long neck has two advantages over the normal pipe to flange connection. First, it does not require pipe piece and second it eliminates a but weld between pipe and flange that required in case of conventional nozzle connection. These types of flanges are normally used in high pressure and temperature application. It is costly but gives high reliability and reduces fabrication efforts as compared to normal pipe to flange type nozzle.


A Nipoflange is used in the pipe industry like a weldolet or a nipolet for a 90° branch connection. A Nipoflange is a combination of weldolet, nipolet and flange.
Two different pipe branch connections
On the run pipe side  a nipoflange is designed like a weldolet. That means the branch connection on the run pipe side is a welding connection. On the other side there it has a flange connection. The flange connection can be designed according to customers requirements (acc. To DIN or ANSI).

Orifice Flanges

Orifice Flanges are used with orifice meters for the purpose of measuring the flow rate of either liquids or gases in the respective pipeline. Orifice flanges generally come with either raised faces or RTJ (Ring Type Joint) facings. They are, for all intensive purposes, the same as weld neck and slip-on flanges with extra machining. They have modifications of radial tapped holes in the flange ring for meter connections and orifice plate carriers for the reason of fitting meter connections. The additional bolts act as a jack to allow the separation of the two flanges to change the orifice plate or for other inspection services.

Plate Flanges

A plate flange  is a flat, circular disk that is welded onto the end of a pipe and allows it to be bolted to another pipe. Typically used in fuel and water pipelines, the two flange plates will be bolted together with a gasket in between them. The flange plate will have bolt holes all around the perimeter and will be used to create junctions, tees and joints.

Ring Type Joint Flanges

A Ring Type Joint Flange (RTJ Flange) is termed for pipelines flange with Ring Type Joint Facing. Any Standard & Non Standard Flanges can be machined for Ring Type Joint Facing. A Ring Type Joint flange (RTJ flange) is basically a Flange Joint connection or more commonly known as a flange facing.

Reducing Flanges

Reducing Flange is reduced bore flange to facilitate connections with other flange smaller than the reducing flange. Often referred as Reducer Flange.
Reducing Flange can be fabricated using a reducing spool with concentric or eccentric reducer & desired flange at each end OR it could be a single flange with internal reduced bore to connect different sized fittings on either sides.
Reducing Flanges need to be described by bigger Inlet size & smaller Outlet size.
These Flanges can be either forged or can be directly machined from heat treated plates. Plate forming is preferable for smaller sized Reducing Flanges.

Slip On Flanges

slip on 1 - What are flanges solutions?

Slip on flanges are slipped over the pipe and welded (usually both inside and outside) to provide strength and prevent leakage. Slip on Flanges are at the low cost end of the scale, and do not require high accuracy when cutting the pipe to length. These slip on can sometimes have a boss or hub, and can be made with a bore to suit either pipe or tube.

The calculated strength from a Slip On flange under internal pressure is of the order of two-thirds that of Welding Neck flanges, and their life under fatigue is about one-third that of the latter.
The connection with the pipe is done with 2 fillet welds, as well at the outside as also at the inside of the flange.
This space is necessary, to do not damage the flange face, during the welding process.
A disadvantage of the flange is, that principle always firstly a pipe must be welded and then just a fitting. A combination of flange and elbow or flange and tee is not possible, because named fittings have not a straight end, that complete slid in the Slip On flange.

Socket Weld Flanges

socket weld 1 - What are flanges solutions?

A Socket Weld Flange is similar to a Slip On Flange, however Socket Weld Flanges have an internal recess on the inside diameter to allow for a smoother flow of the process fluid.

These flanges are developed for use in small diameter, high pressure lines. Internally welded socket type flanges are typically used in chemical process, hydraulic lines and steam distribution lines. They have a counterbore from the hub side slightly larger than the outside diameter of the pipe.
The socket weld flange is similar to a slip-on flange, except only one fillet weld is made to the flange and pipe. These pipe flanges are attached by inserting the pipe into the socket end and applying fillet weld around the top. This allows for a smooth bore and better flow of the fluid or gas inside of the pipe.

Spectacle Blind Flanges

A spectacle blind flange – also known as a figure-8 blind – is generally a piece of metal that is cut to fit between two pipe flanges and usually sandwiched between two gaskets. A spectacle blind flange is often made from two metal discs that are attached to each other by a small section of steel. The shape is similar to a pair of glasses or “spectacles” – hence the name spectacle blind. One end of the blind will have an opening to allow flow through the pipe during operation and the other end is solid to block flow during maintenance. They are generally installed as a permanent device to separate process piping systems.

Spectacle blind and spade and spacerd are the same stuff. all together assembled they make a spectacle blind (which is also called figure 8 since it looks like 8). spade and spacers are basically the same as spectacle blinds, except that both are not attached to each other.
the spacer is made from a metal ring in different type of material, with a welded handle. the spacer function is to allow the passage of the fluid (or gas) in the line); the spade is made from a round piece of different type of material, with a handle furnished in a different form, according to the dimensional standard. in the middle there is a welded handle. see below a drawing for your easy reference and a pic.

Square Flanges

The square flange is used to close ends of piping systems. The Square Flange provides a dependable and long lasting isolation point. The Square Flange is similar in diameter to a standard flange and the laying length is compact, making it easily adaptable for your piping systems.

Spades & Ring Spacers

figure8 2 - What are flanges solutions?

Spades & Ring Spacers are basically the same as Spectacle Blinds, except that both are not attached to each other.

Spades and Spacers be applied in systems where maintenance is often not necessary, or in applications with large pipe sizes. Depending on the flange size and the Pressure Class, Spades can weigh hundreds of pounds.

Threaded Flanges

threaded 1 - What are flanges solutions?

A Threaded Flange is usually confined to a special application. The main benefit of a Threaded Flange is that it can be assembled without welding which makes it perfect for extremely high pressure services.

Threaded flanges are threaded in the bore to match an external thread on the pipe. The threads are tapered to create a seal between the flange and pipe as the tapers approach the same diameter. These flanges are normally designed for low pressure, non-cyclic applications.
hreaded Flanges are used for special circumstances with their main advantage being that they can be attached to the pipe without welding. Sometimes a seal weld is also used in conjunction with the threaded connection. Although still available in most sizes and pressure ratings, screwed fittings today are used almost exclusively in smaller pipe sizes.

Welding Neck Flanges

welding neck 1 - What are flanges solutions?

A weld neck flange is a type of steel flange designed to transfer stresses to the pipe to reduce high stress concentrations at the base of the flange. Compared with other types, weld neck flanges are know for their tapered hub and gentle transition from flange thickness to pipe wall thickness. They are deformation-resistant, and are normally used for high pressure,high or low temperature conditions.
This group of flanges is Designed with a hub on the backside tapering to a diameter that will match the pipe to which it will be welded. These flanges are bored to match the inside diameter of the mating pipe so there will be no restriction of product flow. Generally machined from a forging, these flanges are typically butt welded to a pipe. The rim has a series of drilled holes that permit the flange to be affixed to another flange with bolts. Such flanges are suitable for use in hostile environments that have extremes of temperature, pressure or other sources of stress. The resilience of this type of flange is achieved by sharing the environmental stress with the pipe with which it is welded. This type of flange has been used successfully at pressures up to 5,000 psi.

Specification of the Flanges

flange 4 - What are flanges solutions?

• ASME B16.5, ASME B16.47 (Serie A and Serie B),API 6A, ASME B16.36, ASME B16.48 and MSS SP44 are the key specifications covering the dimensions and the manufacturing tolerances of Flanges. ASME B16.25 covers the preparation of butt weld connections between pipes and Weld Neck Flange. MSS SP25 covers the marking system.
• ASTM A961 is standard specification for common requirements for steel flanges and parts for piping applications.
• The weld neck and socket weld flanges has the same SCH as the mating pipe.

Hydrostatic Test of the Flanges

• Parts manufactured under ASTM A961 shall be capable of passing hydrostatic test compatible with the rating of the finished part. Such test shall be conducted by the supplier only when the hydrostatic test supplementary requirement in the product specification is invoked by the purchaser.

Disadvantage of the Flanges

• Flanged pipe systems need much more space (just think of a pipe rack).
• Each flange connection can leak (some people claim that a flange connection is never 100 percent leak proof).
• Insulation of flanged pipe systems is more expensive (special flange caps).

Cost of the Flanges

• Material costs are low, but labor costs are moderate to high due to the need for specialized welders and fitters.

Size of the Flanges

• FROM 0.5″ TO 60″.
• conformity with the customers drawing.

Other Properties of the Flanges

• Different types of flange faces are used as the contact surfaces to seat the sealing gasket material. ASME B16.5 and B16.47 define various types of flange facings, including the Flat face, raised face and the large male and female facings which have identical dimensions to provide a relatively large contact area.

Materials of the Flanges

The material qualities for these flanges are defined in the ASTM standards. ASTM standards define the specific manufacturing process of the material and determine the exact chemical composition of pipes, fittings and flanges, through percentages of the permitted quantities of carbon, magnesium, nickel, etc., and are indicated by “Grade”.
For example, a carbon steel pipe can be identified with Grade A or B, a stainless-steel pipe with Grade TP304 or Grade TP321, a carbon steel fitting with Grade WPB etc..

flange material 3 - What are flanges solutions?
Below you will find as an example tables with chemical requirements for:

  • Flanges according to ASTM A182 Grade F304, F304L F316L.
  • Furthermore, a table with frequently used ASTM Grades, arranged on Pipes, Fittings, Flanges, Valves, Bolts & Nuts, which belong together as a group.
  • As you may be have noted, ASTM A105 has no Grade. Sometimes ASTM A105N is described.
  • N stands not for Grade, but for normalized. Normalizing is a type of heat treatment, applicable to ferrous metals only. The purpose of normalizing is to remove the internal stresses induced by heat treating, casting, forming etc..

Carbon Steel

  • ASTM A105/ A105 M-98, ASTM A181 M-95 b Class 60, ASTM A181 M-95 b Class 70,
  • ASTM A694/ A694M (F42, F46, F48, F50, F52, F56, F60, F65, F70)
  • ASTM A515/ A515M (Gr.55, 60, 65, 70)

ASTM A105/ A105 M-98, This specification covers standards for forged carbon steel piping components, that is, flanges, fittings, valves, and similar parts, for use in pressure systems at ambient and higher-temperature service conditions. Materials shall be subjected to heat treatment (annealing, normalizing, tempering, or quenching). Material shall conform to carbon, manganese, phosphorus, sulfur, silicon, copper, nickel, chromium, molybdenum and vanadium contents. The forgings shall be subjected to tension, hardness and hydrostatic tests, with the latter applicable when required. Material shall adhere to tensile strength, yield strength, elongation, reduction of area, and hardness requirements. Guidelines for retreatment, repair by welding, and product marking are given.
ASTM A181 M-95 b Class 60, ASTM A181 M-95 b Class 70, his specification covers nonstandard as-forged fittings, valve components, and parts for general service. Forgings made to this specification are limited to a maximum weight of 10 000 lb [4540 kg]. Larger forgings may be ordered to Specification A266/A266M.
ASTM A694/ A694M (F42, F46, F48, F50, F52, F56, F60, F65, F70), This specification covers carbon and alloy steel forgings for pipe flanges, fittings, valves, and parts for high-pressure transmission service. A chemical heat analysis of the steel shall be made, and the steel shall conform to specified chemical composition requirements. Materials adhere to testing and tensile property requirements as well.
ASTM A515/ A515M (Gr.55, 60, 65, 70), This specification covers carbon-silicon steel plates primarily for intermediate- and higher-temperature service in welded boilers and other pressure vessels. Plates are available in three grades having different strength levels: Grade 60; Grade 65; and Grade 70. The steel shall be killed and made to a coarse austenitic grain size practice. The steel shall conform to the chemical requirements specified. Tension test shall be made to conform to the requirements specified.

Low Temperature Carbon Steel

  • ASTM A350/ A350M-99(LF1, LF2, LF3, LF5, LF6, LF9, LF787),
  • ASTM A707/ A707M(L1, L2, L3, L4, L5, L5, L6, L7, L8)
  • ASTM A516/ A516M (Gr. 60, 65, 70)

ASTM A350/ A350M-99(LF1, LF2, LF3, LF5, LF6, LF9, LF787), This specification covers several grades of carbon and low alloy steel forged or ring-rolled flanges, forged fittings and valves for low-temperature service. The steel specimens shall be melt processed using open-hearth, basic oxygen, electric furnace or vacuum-induction melting. A sufficient discard shall be made to secure freedom from injurious piping and undue segregation. The materials shall be forged and shall undergo heat treatment such as normalizing, tempering, quenching and precipitation heat treatment. Heat analysis and product analysis shall be performed wherein the steel materials shall conform to the required chemical compositions of carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, copper, columbium, vanadium, and nitrogen. The materials shall also undergo tension tests and shall conform to the required values of tensile strength, yield strength and elongation. Impact tests shall also be performed and the steel materials shall conform to the required values of minimum impact energy, temperature, and minimum equivalent absorbed energy. Hardness and hydrostatic tests shall also be performed.
ASTM A707/ A707M(L1, L2, L3, L4, L5, L5, L6, L7, L8), This specification covers forged carbon and alloy steel flanges intended primarily for petroleum and gas pipelines in areas subject to low ambient temperatures. Eight grades, four yield-strength classes, and three different notch toughness levels are included. All material shall be heat treated by annealing, normalizing, precipitation hardening, quenching-and-tempering, normalizing-and-tempering, normalizing-and-precipitation hardening, or quenching-and-precipitation hardening. A chemical heat analysis shall be made and conform to the requirements as to chemical composition specified. The material in the weld neck shall conform to the mechanical property requirements specified. Hardness test, impact test, ultrasonic test, tension test, and hydrostatic test shall be made to conform to the specified requirements.
ASTM A516/ A516M (Gr. 60, 65, 70), This specification covers carbon steel plates intended primarily for service in welded pressure vessels where improved notch toughness is important. According to different strength levels, the plates are available in four grades: Grades 55, 60, 65, and 70. The maximum thickness of plates is limited only by the capacity of the composition to meet the specified mechanical property requirements. The steel shall be killed and shall conform to fine austenitic grain size requirements. The mechanical properties such as tensile strength, yield strength, and elongation shall be determined by a tension test for the plates.

Stainless Steel

  • ASTM A182/ A182 M-98ª(F304, F304H, F304L, F304N, F304 LN, F309H, F310, F310H, F310 MoLN, F316, F316H, F316L, F316N, F316LN, F317, F317L, F347, F347 H, F348, F348 H, F321, F321 H)
  • ASTM A240/ A240M( 304,310, 316)

ASTM A182/ A182 M-98ª(F 304, F 304H, F 304L, F 304N, F304 LN, F 309H, F310, F 310H, F 310 MoLN, F 316, F 316H, F 316L, F 316N, F 316LN, F 317, F 317L, F 347, F 347 H, F 348, F 348 H, F 321, F321 H), This specification covers forged or rolled alloy and stainless steel pipe flanges, forged fittings, and valves and parts for high-temperature service. After hot working, forgings shall be cooled to a specific temperature prior to heat treatment, which shall be performed in accordance with certain requirements such as heat treatment type, austenitizing/solution temperature, cooling media, and quenching. The materials shall conform to the required chemical composition for carbon, manganese, phosphorus, silicon, nickel, chromium, molybdenum, columbium, titanium. The material shall conform to the requirements as to mechanical properties for the grade ordered such as tensile strength, yield strength, elongation, Brinell hardness. All H grades and grade F 63 shall be tested for average grain size.
ASTM A240/ A240M( 304,310, 316), This specification covers chromium, chromium-nickel, and chromium-manganese-nickel stainless steel plate, sheet, and strip for pressure vessels and for general applications. The steel shall conform to the requirements as to chemical composition specified. The material shall conform to the mechanical properties specified.

Alloy Steel & High Yield Steel

  • ASTM A182/ A182 M-98a( F1, F2, F5, F5a, F9, F91, F92, F911, F11 Class 1, F11 Class 2, F11 Class 2, F12 Class 1, F12 Class 2,F21 F3V, F21 3VCb, F22 Class 1, F22 Class 3, F23, F24, FR)
  • ASTM A387/ A387M(Gr.2, 12, 11, 22, 22L, 21, 21L, 5, 9, 91)

This specification covers forged or rolled alloy and stainless steel pipe flanges, forged fittings, and valves and parts for high-temperature service. After hot working, forgings shall be cooled to a specific temperature prior to heat treatment, which shall be performed in accordance with certain requirements such as heat treatment type, austenitizing/solution temperature, cooling media, and quenching. The materials shall conform to the required chemical composition for carbon, manganese, phosphorus, silicon, nickel, chromium, molybdenum, columbium, titanium. The material shall conform to the requirements as to mechanical properties for the grade ordered such as tensile strength, yield strength, elongation, Brinell hardness. All H grades and grade F 63 shall be tested for average grain size.

Duplex Steel

  • ASTM A182 (F50, F51, F52, F53M F54, F55, F57, F59, F60, F61, F904L)

This specification covers forged or rolled alloy and stainless steel pipe flanges, forged fittings, and valves and parts for high-temperature service. After hot working, forgings shall be cooled to a specific temperature prior to heat treatment, which shall be performed in accordance with certain requirements such as heat treatment type, austenitizing/solution temperature, cooling media, and quenching. The materials shall conform to the required chemical composition for carbon, manganese, phosphorus, silicon, nickel, chromium, molybdenum, columbium, titanium. The material shall conform to the requirements as to mechanical properties for the grade ordered such as tensile strength, yield strength, elongation, Brinell hardness. All H grades and grade F 63 shall be tested for average grain size.

Nickel Alloy

  • SB 564(UNS N02200, UNS N04400, UNS N06022, UNS N06025, UNS N06035, UNS N06045, UNS N06058, UNS N06059, UNS N06110), specification for nickel alloy forgings

Standard of the Flanges

Flange dimensions are determined by the pipe size and the pressure class required for the application. Flanges are standardized according publications from organizations like ASME, MSS, API and others.
Each flange according to ASME B16.5 has a number of standard dimensions. If a draftsman in Japan or a work preparer in Canada or a pipefitter in Australia is speaking about a Welding Neck flange NPS 6, Class 150, Schedule 40 ASME B16.5, then it goes over the flange which in the image here below is shown.
If the flange is ordered, the supplier want to know the material quality. For example ASTM A105 is a forged carbon steel flange, while A182 is a forged stainless steel flange.
So, in a correct order to a supplier two standards must be specified:

flange standards 2 - What are flanges solutions?

The flange above has 8 bolt holes, and a welding bevel of 37.5 degrees (red circle). All given dimensions are in millimeters. The raised face (RF) does not need to be specified, because according to ASME B16.5, each flange is standard delivered with a raised face. Only a different design (Ring Type Joint (RTJ), Flat Face (FF) etc.), should be specified.

ASME B16.5, ASME B16.47 (Serie A and Serie B), API 6A ASME B16.36, ASME B16.48 and MSS SP44 are the key specifications covering the dimensions and the manufacturing tolerances of Flanges. ASME B16.25 covers the preparation of butt weld connections between pipes and Weld Neck Flange. MSS SP25 covers the marking system.

ASME B16.5

ASME B16.5 Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, testing, and methods of designating openings for pipe flanges and flanged fittings. Included are: flanges with rating class designations 150, 300, 400, 600, 900, and 1500 in sizes NPS 1/2 through NPS 24 and flanges with rating class designation 2500 in sizes NPS 1/2 through NPS 12.

ASME B16.47 (Serie A and Serie B), MSS-SP44

Large Diameter Steel Flanges, NPS 26 through NPS 60 Metric/Inch Standard, Weld Neck, Slip-On, Blind. Class 150 to Class 900.


API Spec 6A and MSS SP-44 specify all flanges commonly used in surface drilling and production. These flanges have a long history and many flanges used in the past have been discontinued, or obsoleted and replaced by more modern configurations. Originally, all flanges related to pipe and became standard as weld neck, threaded and blind configurations. As equipment with integral flanges came to the oilfield, standardization became necessary for functional interchangeability.

ASME B16.36

This Standard covers flanges (similar to those covered in ASME B16.5) that have orifice pressure differential connections. Coverage is limited to the following: (a) welding neck flanges Classes 300, 400, 600, 900, 1500, and 2500 (b) slip-on and threaded Class 300.

ASME B16.48

This Standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for operational line blanks in sizes NPS 1/2 through NPS 24 for installation between ASME B16.5 flanges in the 150, 300, 600, 900, 1500, and 2500 pressure classes.

Manufacturing Process of the Flanges

flange manufacturing process 1 - What are flanges solutions?

Forging is a manufacturing process involving the shaping of metal using localized compressive forces. The blows are delivered with a hammer (often a power hammer) or a die. Forging is often classified according to the temperature at which it is performed: cold forging (a type of cold working), warm forging, or hot forging (a type of hot working). For the latter two, the metal is heated, usually in a forge.
Understanding customer’s requirement and ensuring to supply as per these requirements is realised with the help of quality assurance at Petrosadid one of the market leader, our product range include all types of flanges such as MS Flange (Mild Steel), Raised face flange, welding neck, Long weld neck, Slip on, threaded, blind, figure8, spectacle blind, spade and space, etc.

  • Raw Material→Material Inspection→Material Cutting→Flange Forging→Heat Treatment→Forging Rolling→Final Inspection→Rust Prevention→Packing and Shipment

flange manufacturing process 2 - What are flanges solutions?

Raw Material

• Raw Material Check
• Quantity Check
• Visual & Dimension Check
flange manufacturing process 3 - What are flanges solutions?

Material Inspection

• Chemical Analysis Check
• Preservation Analysis Certificate
flange manufacturing process 4 - What are flanges solutions?

Material Cutting

• Weight Measuring
• Cut Surface Check
• Marking
flange manufacturing process 5 - What are flanges solutions?

Flange Forging

• Material Grade Check
• Weight Measuring
• Temperature Control
flange manufacturing process 6 - What are flanges solutions?

Heat Treatment

• Normalizing
• Tempering, Q.T
• Solution Treatment
• Mechanical Test
flange manufacturing process 7 - What are flanges solutions?

Forging Rolling

• Weight Measuring
• Cut Surface Check
• Marking
flange manufacturing process 8 - What are flanges solutions?

Final Inspection

• Dimension size inspect
• Visual Test
• Nondestructive Test

1 153714 1 - What are flanges solutions?

Inspection process of flanges

Advanced testing instruments and equipment are a strong guarantee for production and processing quality. The company is equipped with advanced spectrometer, chemical analyzer, metallographic microscope, hardness tester and universal material testing machine. It has introduced advanced testing equipment such as projector, roundness instrument, metallographic microscope and CMM from Japan. Relying on advanced equipment, the company constantly carries out standardized training for testing operators, formulates its own processes and specifications in accordance with the international quality management system, and constantly pursues the perfection of quality.

flange manufacturing process 9 - What are flanges solutions?

Rust Prevention

• Preserve Check
• Marking on the flange
• Pickling ,Coating
flange manufacturing process 10 - What are flanges solutions?

Packing and Shipment

• Packing Spec. Check
• Packing Inspection
• Delivery

Flange installation

Flange type installation is flange connection, which is a detachable joint of two pipes, fittings or equipment, each fixed on a flange first, then adding flange gasket between the two flanges, and finally using bolts to tighten the two flanges to make them tightly combined.
The main features of flange connection are easy disassembly, high strength and good sealing performance. When installing the flange, two flanges are required to be kept parallel, and the sealing surface of the flange cannot be touched and cleaned. Flange gasket, to be selected according to the design provisions.
General low pressure small diameter with wire flange, high pressure and low pressure large diameter with welding flange, the thickness of the flange and the diameter and number of connecting bolts of different pressure is different.
Flange connection can generally be divided into five types: namely, flat welding, butt welding, socket welding, loose-fitting, threaded.

  • 1. Flat welding: only with welding the outer layer, without welding the inner layer; generally commonly used in medium and low pressure pipelines, the nominal pressure of the pipeline to be lower than 0.25MPa.
  • 2. Butt welding: the inner and outer layers of the flange are to be welded, generally used in medium and high pressure pipelines, the nominal pressure of the pipeline between 0.25 ~ 2.5MPa.
  • 3. Socket welding: generally used for nominal pressure less than or equal to 10.0MPa, nominal diameter less than or equal to 40mm in the pipeline.
  • 4. Loose-fitting: generally used for pressure is not high but in which the medium is more corrosive pipeline, so this type of flange corrosion resistance, the material is mostly stainless steel.

How to check the flange installation and what are the specific operating procedures?

Connection flange is usually we are connected to the pipeline, or the pipeline above the accessories can be connected. If the connection is not good, it will directly affect the use of the pipeline, so generally after the installation of the flange we have to check to ensure that the flange connection is accurate, the key can be used normally. So how to check the flange installation, what is the specific process to be carried out?
The first step, we have to choose to prepare the tools needed to check, steel tape measure, steel ruler, level, etc., the tools needed to check these, but is not limited to these. But one thing to note that the flange installation you have to prepare and use the tools must be in a qualified calibration, and to be within the validity period, otherwise it is easy to bring errors for your inspection, resulting in instability of detection.
The second step, as the flange installation personnel to understand the key to the installation of the flange, similar to the torsion torque and other issues, the tools required for installation to be within the qualified calibration, the equipment to be installed to have a valid inspection certificate, to have the conditions of construction. Also determine the flange specifications, as well as the number, type, etc. is correct.
The third step, the installation should check the flange sealing surface, gaskets and other materials, types correct, but also pay attention to see whether the formal sealing gasket and flange sealing surface is scratched, is not clean, where the gasket is prohibited for a second time, but also to check whether the cleanliness of the pipe or equipment inside the qualified. After installation, it is necessary to witness the torsion torque according to the drawing requirements and adjust it appropriately to ensure correct installation and reasonable torque. After the installation is completed to check the balance of the flange, this time to take four points on two diameters perpendicular to each other, the same diameter of the two points to be in the outer edge of the flange, 90 ° apart at four points using vernier calipers and other appropriate tools to check the parallelism of the flange.

Flange management

Flange is a kind of connecting part, which plays an important role in ensuring the tightness between penstock, valves and various equipment. Combined with the penstock construction of ichthys module, this paper explains the control measures for the tightness of flange installation, mainly including material control, quality control during welding and quality control during connection and assembly. Only through reasonable material selection, correct installation (implementation of standards and specifications) and safe operation can we ensure the safe and stable long-term operation of the production plant.
All kinds of pressure pipelines, valves and equipment are mostly connected in the form of flanges. The operation safety of pressure pipelines is directly related to the quality of flange connection. If the flange is not tightly sealed during assembly and connection, it will cause pipeline leakage and become a greater potential safety hazard. Therefore, it is very necessary to pay attention to and do a good job in flange management.
Flange management refers to the general term of activities such as flange storage, welding and assembly, bolt fastening, on-site inspection, listing and data preparation. The whole process management is implemented within the scope of prefabrication, installation and construction, trial operation and operation. Its advantage is to realize strict inspection of materials, effectively control welding errors and standardize various installation operations, Solve the leakage problem caused by uneven flange fastening, so as to improve the safety performance.
As an important connecting part between pipes, valves and equipment, flange has strict requirements on its own quality. It is necessary to ensure the specification and model of materials from the source and standardize the installation and operation in the process:

  • 1) When the flange is supplied, the material engineer shall organize the acceptance to meet the design requirements. The acceptance contents include appearance, internal and external diameter, bolt hole center distance and flange height.
  • 2) After the flange passes the acceptance, measures such as coating anti rust oil and fastening flange cap shall be taken in time, and then transported to the warehouse for storage.
  • 3) The storage of flanges shall be carried out on the shelves in separate areas, follow the principle of layered and classified stacking, and make marks to facilitate picking up.
  • 4) Receive materials as required. During the transportation of flanges, pay attention to protect the flange sealing surface to prevent the loss of flange cap.

Application of flanges

Widely used in petroleum, chemical, nuclear power plant, food manufacturing, construction, shipbuilding, paper making, pharmaceutical and other industries, there are different uses in different industries, showing the use value. Yaang believes that different flanges have different production standards in use and production, and the production and use according to the corresponding standards can ensure the use value and the actual role of special flanges. The new 200 series steel production and use of these products the expansion of the user and the lack of sufficient understanding and know the reality is not adapted. Thermal conductivity: for floor heating pipes need to have good thermal conductivity, low temperature heat impact low temperature impact resistance is better. Heating temperature is high, the thickness of the stamping elbow increases.
Usually the role of the flange has three main points.

  • One is used to connect the pipeline and ensure that the pipeline remains sealed.
  • The second is to facilitate the replacement of a section of the pipeline.
  • The third is convenient to disassemble and check the pipeline at any time.

Stainless steel flange use precautions

  • 1. Stainless steel flange in the welding time, subject to repeated heating precipitation carbide, will reduce the stainless steel flange to reduce corrosion resistance and mechanical properties.
  • 2. Stainless steel flanges in use should be kept dry, titanium calcium type should be dried by 150 ℃ for 1 hour, low a hydrogen type should be dried by 200-250 ℃ for 1 hour (can not be repeated drying, otherwise the flux skin is easy to crack and flake), to prevent the welding electrode flux skin sticky oil and other dirt, so as not to cause the weld to increase the carbon content and affect the quality of stainless steel flanges.
  • 3. Chrome stainless steel flange fittings after welding hardening American Standard flange larger, easy to produce cracks, if the same type of chrome stainless steel welding rod (G202, G207) welding, must be more than 300 ℃ preheating and welding about 700 ℃ after the slow cooling treatment, if the welded parts can not be post-weld heat treatment, the stainless steel flange fittings should be used welding rod (A107, A207).
  • 4. Stainless steel flange, in order to improve corrosion resistance and weldability and appropriate increase the appropriate amount of stability elements Ti, Nb, Mo, etc., weldability than chromium stainless steel flange some good, using the same type of chromium stainless steel flange welding rod (G302, G307), should be more than 200 ℃ preheating and tempering treatment after welding about 800 ℃, if the weld can not be heat treatment, then the stainless steel flange fittings welding rod (A107, A207) should be used.
  • 5. In order to prevent inter-eye corrosion due to stainless steel flange cover heating, welding current should not be too large, about 20% less than carbon steel welding rod, the arc should not be too long, interlayer fast cooling, to narrow welding channel is appropriate.

How to get cost-effective flange solutions?

20231010081833 22043 - What are flanges solutions?

1. Look at the price of stainless steel flanges.

Different flanges have different prices, however, the price of stainless steel flanges is not a roaming price, with its production process, brand, etc. are very relevant, the price is different, the same specification of stainless steel flange prices are not similar, but if you find yourself buying stainless steel flange is much lower than the market price, then do not buy, so as not to buy inferior products.
2. Look at the classification of stainless steel flanges.
Stainless steel flange is only a large category, there are many small categories, not every type of stainless steel flange prices are the same, so that different categories of stainless steel flange in terms of price also has a certain difference, so that we are in the choice of stainless steel flange, be sure to figure out the classification of their needs, different kinds of stainless steel flange prices are different, in terms of specific uses are also different.
3. Look at the brand of stainless steel flanges.
It seems that in every industry there are so many high-profile brands, high-profile brands in quality, quality, production process, and after-sales service and other aspects are very secure, at the same time, stainless steel flanges also have many brands, different manufacturers of stainless steel flanges in quality and quality are different, performance, corrosion prevention aspects are different. We can choose the more famous brand when buying stainless steel flanges, so that the quality is relatively very secure.

Source: China Flanges Solutions Supplier – Yaang Pipe Industry (

(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]



Leave a Reply



Inquery now



WhatsApp Skype

Wechat: 8618267732328

  • Email me
    Mail to us