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ASTM B677 UNS N08926 Seamless Pipe

Size: 3/4" (DN20/26.7mm)
Wall thickness: SCH80S (3.91mm)
Material: Alloy 926 (UNS N08926/Incoloy 926)
Length: 2M


Type: UNS N08926 Seamless Pipe
Material: Alloy 926 (UNS N08926/Incoloy 926)

  • Pipe OD: 42.2-508.0MM; WT: 1.65-53.98MM.
  • Tube OD: 10.3- 33.4MM; WT: 1.24-9.09MM.

Standard: ASTM B677

Length: Normally fixed length 6m, can as per customer’s requirement.

End: Beveled End,Plain End

What is UNS N08926 pipe?

UNS N08926 pipe is a super austenitic molybdenum stainless steel pipe with excellent corrosion resistance to a variety of highly corrosive environments. 6% molybdenum, high nickel and nitrogen alloyed austenitic grades provide extremely high uniform and localized corrosion resistance. The combination of molybdenum and nitrogen in its composition resists pitting and crevice corrosion, while copper improves sulfuric acid resistance and nitrogen improves yield and tensile strength. Alloy 926 pipe is extremely resistant to pitting and crevice corrosion in halide media. Excellent general resistance to a wide range of media in the environment, including oxidizing and reducing media. Mechanical properties are superior to AISI 904L alloy pipe.

Equivalent Gradesof of UNS N08926

NAS Alloy ASTM A240/B625 EN Material No.
NAS 255NM Incoloy 926 UNS N08926 X1NiCrMoCuN25-20-7 1.4529

Chemical Composition of ASTM B677 / ASME SB677 / UNS N08904, UNS N08925, and UNS N08926

Element UNS N08904 UNS N08925 UNS N08926 Product(Check) Analysis Variations, under min or over max of the Specified Limit of Element, %
UNS N08904 UNS N08926
UNS N08925
Carbon, max 0.02 0.02 0.02 0.0005 0.005
Manganese, max 2 1 2 0.04 0.04
Phosphorus, max 0.045 0.045 0.03 0.005 0.05
Sulfur, max 0.035 0.035 0.01 0.005 0.003
Silicon, max 1 0.5 0.5 0.05 0.03
Nickel 23.0 to 28.0 24.0 to 26.0 24.00 to 26.00 0.2 0.25
Chromium 19.0 to 23.0 19.0 to 21.0 19.00 to 21.00 0.2 0.25
Molygdenum 4.0 to 5.0 6.0 to 7.0 6.0 to 7.0 0.1 0.15
Copper 1.0 to 2.0 0.8 to 1.5 0.5 to 1.5 0.1 0.04
Nitrogen 0.1 to 0.2 0.1 to 0.2 0.01
IronA balance balance balance ….

Mechanical Properties of ASTM B677 / ASME SB677 / UNS N08904, UNS N08925, and UNS N08926

Alloy Temper Tensile Strength, min, psi(MPa) Yield Strength, 0.2% offset, min, psi(MPa) Elongation in 2 in. or 50mm(or 4D),min, %
UNS N08904 Sloution Annealed 71(490) 31(220) 35
USN N08925 Sloution Annealed 87(600) 430(300) 40
UNS N08926 Sloution Annealed 94(650) 43(295) 35

Physical properties of ASTM B677 / ASME SB677 / UNS N08904, UNS N08925, and UNS N08926

Density [g/cm3] 8.1
Specific heat [J/kg . K] 466
Electrical resistivity [μΩ . cm] 94.7
Thermal conductivity [W/m . K] 11.8
Average coefficient of thermal expansion [10–6/°C] 20-100°C 15
20-200°C 15.4
20-300°C 15.8
20-400°C 16.1
Young’s modulus [MPa] 21.1 × 104
Magnetism None
Melting range [°C] 1320-1390
Hardness (HB 30) ≤ 250

Corrosion resistance of UNS N08926

Uniform corrosion
Uniform corrosion occurs when all or at least most of the passivated layer is destroyed. This usually occurs in acid or hot alkaline solutions. The effect of alloy composition on uniform corrosion resistance may vary significantly between environments; chromium is essential to ensure passivation of stainless steels, nickel helps to reduce the corrosion rate of depassivated steels, molybdenum enhances passivation (except in strongly oxidizing environments such as warm concentrated nitric acid), and copper has a positive effect in the presence of reducing acids such as dilute sulfuric acid. In environments with constant temperature and chemical composition, uniform corrosion occurs at a steady rate. The rate is usually expressed as a loss of thickness per unit of time, e.g. mm/y. In environments where the corrosion rate does not exceed 0.1 mm/y, stainless steel is usually considered resistant to uniform corrosion. Impurities may seriously affect the corrosiveness of acid solutions. For guidance on selecting materials in a large number of environments capable of causing uniform corrosion, refer to the tables and iso corrosion charts.
Pitting and crevice corrosion

In neutral or acidic environments chloride ions contribute to the local breakdown of the passivation layer. Therefore, pitting and crevice corrosion can propagate at high speed and cause corrosion failure in a short period of time. Because the erosion is small and may be covered by corrosion products or hidden in cracks, it is usually undetected until a perforation or leak occurs. Resistance to pitting corrosion depends primarily on the chromium, molybdenum and nitrogen content of the stainless steel. This is usually illustrated by the pitting resistance equivalent (PRE) of the material, which can be calculated by the following formula: PRE = %Cr + 3.3 x %Mo + 16 x %N. The PRE value can be used for a rough comparison of different materials. However, a more reliable method is to grade the steel according to the critical pitting temperature (CPT) of the material. There are several different methods available, such as ASTM G 150, using an Avesta cell with a 1M NaCl solution (35,000 ppm or mg/l chloride ion). CPT values are shown in the table below. The higher chromium, molybdenum and nitrogen content also improves the crevice corrosion resistance of stainless steel. Typical values for critical crevice corrosion temperature (CCT) in 6% FeCl3+1% HCl according to ASTM G48 method F are included in the table below. CPT and CCT values vary with product shape and surface finish, and the values given apply to the ground. astm G150 and G48 are both methods for ranking the relative resistance to pitting or crevice corrosion of different stainless steels, but they do not give the maximum temperature at which these alloys can be used in actual service environments.
Table CPT meets ASTM G150 requirements for wet grinding to 320 grit

Pitting corrosion resistance Crevice corrosion resistance
45 >90 35

Pre-pitting corrosion resistance equivalents in 1M NaCl solution (35000 ppm or mg/l chloride ions) calculated using the following equation: PRE = %Cr + 3.3 x%Mo + 16 x%NCPT corrosion pitting temperature measured in an Avesta cell (ASTM G 150).CCT critical crevice corrosion temperature is based on ASTM G 48 method F by laboratory tests The critical crevice corrosion temperature is obtained by laboratory tests according to ASTM G 48 Method F.

What are the characteristics of UNS N08926?

  • Seawater Handling Equipment
  • Pulp Mill Bleach Systems
  • Tall Oil Distillation Columns and Equipment
  • Chemical Processing Equipment
  • Food Processing Equipment
  • Desalination Equipment
  • Flue Gas Desulfurization Scrubbers
  • Oil and Gas Production Equipment

1.4529 (alloy 926) is a high molybdenum low carbon austenitic special steel. The main applications are in the chemical, paper, cryogenic, aerospace and power industries. Major end products are heat exchangers, chemical tanks, pumps, screws, aircraft components, bushings, shafts, desalination and flue gas desulfurization equipment, steel pipes, flanges, valves, and even radiator components.
Our product range in 1.4529 is pipes, fittings and flanges, accessories.

Production chart of UNS N08926 Seamless Pipe

20220816012700 30763 - ASTM B677 UNS N08926 Seamless Pipe

1. Cold Rolling (Cold drawn) Pipe Production Processes
Round Pipe Billet → Heating → Perforation → Head → Annealing → Pickling → Oil (Copper) → Multi Pass Drawing (Cold Rolling) → Billet → Heat Treatment → Straightening → Water Pressure Test → Marking → Storage
2. Hot Rolling Pipe Production Processes
Round Pipe Billet → Heating → Perforation → Three Roll Skew Rolling, Continuous Rolling or Extrusion → Off Pipe → Sizing (Or Reducing Diameter)→ Cooling → Billet → Straightening → Water Pressure Test ( Or Flaw Detection) → Marking → Storage
3. Longitudinal Welding (Straight Seam Welding) Pipe Production Processes
Including ERW, EFW.

In what applications are UNS N08904, UNS N08925, and UNS N08926 used?

  • Food processing equipment.
  • Marine and offshore engineering.
  • Salt production.
  • Caustic handling equipment.
  • Manufacture and handling of sodium hydroxide, particularly at temperatures above 300° F.
  • Reactors and vessels in which fluorine is generated and reacted with hydrocarbons.

Steel pipe wall thickness (ASME B36.10 & B36.19)

Nominal Pipe Size Outside diameter Wall thickness
1/8″ 10.29 1.24 1.73 2.41
1/4″ 13.72 1.65 2.24 3.02
3/8″ 17.15 1.65 2.31 3.2
1/2″ 21.34 1.65 2.11 2.77 3.73 4.75 7.47
 3/4″ 26.67 1.65 2.11 2.87 3.91 5.54 7.82
1″ 33.4 1.65 2.77 3.38 4.55 6.35 9.09
1 1/4″ 42.16 1.65 2.77 3.56 4.85 6.35 9.7
1 1/2″ 48.26 1.65 2.77 3.68 5.08 7.14 10.16
2″ 60.33 1.65 2.77 3.91 5.54 8.71 11.07
2 1/2″ 73.03 2.11 3.05 5.16 7.01 9.53 14.02
3″ 88.9 2.11 3.05 5.49 7.62 11.13 15.24
3 1/2″ 101.6 2.11 3.05 5.74 8.08 16.15
4″ 114.3 2.11 3.05 6.02 8.56 13.49 17.12
5″ 141.3 2.77 3.4 6.55 9.53 15.88 19.05
6″ 168.28 2.77 3.4 7.11 10.97 18.24 21.95
8″ 219.08 2.77 3.76 8.18 12.7 23.01 22.23
10″ 273.05 3.4 4.19 9.27 12.7 28.58 25.4
12″ 323.85 3.96 4.57 9.53 12.7 33.32 25.4
14″ 355.6 3.96 4.78 9.53 12.7 35.71
16″ 406.4 4.19 4.78 9.53 12.7 40.46
18″ 457.2 4.19 4.78 9.53 12.7 45.24
20″ 508 4.78 5.54 9.53 12.7 49.99
22″ 558.8 4.78 5.54 9.53 12.7 53.97
24″ 609.6 5.54 6.35 9.53 12.7 59.51
The dimensions are in millimeters
Sources : ASME B36.19, ASME B36.10


  • (1) Pipe and tube having a nominal wall thickness fo 3% or less of the nominal ouside diameter. The mean outside diameter shall conform to the permissible variations of Table 3 and individual measurements (including ovality) shall conform to the plus and minus values of the table, with the values increased by 0.5% of the nominal ouside diameter.
  • (2) The mean ouside diameter for pipe and tube over 4 1/2 in. (114 mm) in outside diameter with a nominal wall thickness greater than 3% of the nominal ouside diameter shall conform to the permissible variations of this table, and individual measurements shall not exceed twice the permissible variations of the table.

Specified Outside Diameter Permissible Variations
Outside Thickness of Specified  Thickness of Specifined 
Diameter, in (mm) Average Wall, % Minimum Wall, %
Plus Minus Plus Minus Plus Minus
Cold-Worked Pipe and Tube:
0.500(13) to 5/8(16), excl 0.005(0.13) 0.005(0.13) 15 15 30 0
5/8(16) to 1 1/2(38), incl 0.0075(0.19) 0.0075(0.19) 10 10 20 0
Over 1 1/2(38) to 3 1/2(89), incl 0.010(0.25) 0.010(0.25) 10 10 22 0
Over 3 1/2(89) to 4 1/2(114), incl 0.015(0.38) 0.015(0.38) 10 10 22 0
Over 4 1/2(114) to 3 1/2(152), incl 0.020(0.51) 0.020(0.51) 12.5 12.5 25 0
Over 6(152) to 6 1/2(168), incl 0.25(0.64) 0.25(0.64) 12.5 12.5 25 0
Hot-Finished Tube A,B:
1 1/2(38.1) to 5 1/2(139.7), excl 0.031(0.79) 0.031(0.79) 12.5 12.5 28.5 0
5 1/2(139.7) to 9 1/2(234.5) incl 0.047(1.19) 0.047(1.19) 12.5 12.5 28.5 0

  • A. The wall thickness tolerances for hot-finished tubes includeseccentricity tolerance up to ±12.5%.
  • B. For hot-finished 5 in. (127.0mm) and under in outside diameter, the tolerances on the ouside diameter apply for individual measurements and include ovality. For tubes over 5 in. ion outside diameter, the mean ouside diameter shall comform to the permissible variations of this table andindividual measurements shall not be twice the permissible variations for this table.

Processing and heat treatment of incoloy 926 (UNS N08926/W.Nr.1.4529)

Incoloy 926 nickel-based alloy is suitable for cold and hot processing and machining, but due to its high strength, cold and hot processing requires high-power processing equipment.  

Heating of Incoloy 926 (UNS N08926/W.NR.1.4529)

It is important that the workpieces are clean and free of any contaminations before and during heat treatment. Sulfur, phosphorus, lead and other low-melting point metals can result in material damage during the heat treatment. This type of contamination is also contained in marking and temperature-indicating paints or pens, and also in lubricating grease, oils, fuels and similar materials. The sulfur content of fuels must be as low as possible. Natural gas should contain less than 0.1 wt.-% of sulfur. Heating oil with a maximum sulfur content of 0.5 wt.-% is also suitable. Electric furnaces are preferable for their precise temperature control and a lack of contaminations from fuels. The furnace temperature should be set between neutral and slightly oxidizing and it should not change between oxidizing and reducing. The workpieces must not come in direct contact with flames.

  • (1) Keep the workpiece clean before and during heat treatment.
  • (2) Do not touch sulfur, phosphorus, lead and other low melting point metals during the heat treatment process, otherwise it will damage the performance of the material. Care should be taken to remove dirt such as marking paint, temperature indicating paint, colored crayons, lubricating oil, fuel, etc.
  • (3) The lower the sulfur content in the fuel, the better. The sulfur content in natural gas should be less than 0.1%, and the sulfur content in heavy oil should be less than 0.5%.
  • (4) Considering the need for temperature control and keeping clean, it is best to conduct heat treatment in a vacuum furnace or a gas shielded furnace.
  • (5) It can also be heated in a box furnace or a gas furnace, but the furnace gas must be clean and neutral to slightly oxidizing. The furnace gas should be avoided from fluctuating between oxidizing and reducing properties. The heating flame cannot be directly heated. Burn to the workpiece.

Thermal Processing of Incoloy 926 (UNS N08926/W.NR.1.4529)

  • (1) The thermal processing temperature of Incoloy 926 (N08926) alloy ranges from 1200°C to 900°C, and the cooling method is water quenching or rapid air cooling.
  • (2) When heating, the material can be directly fed into the furnace that has been heated to the highest working temperature. After holding for sufficient time (60 minutes of holding time per 100mm thickness) is quickly released, and the heating is carried out in the high temperature section of the specified temperature range. Processing. When the material temperature drops below the thermal processing temperature, it needs to be reheated. 
  • (3) In order to get the best performance, solution treatment should be carried out after thermal processing.  

Hot forming OF INCOLOY 926 (UNS N08926/W.NR.1.4529)

Alloy 926 can be hot-formed in a temperature range between 1,200 and 900 °C (2,192 and 1,652 °F) with subsequent rapid cooling down in water or air. For heating up, workpieces should be placed in a furnace that is already heated up to 1,200 °C (2,192 °F). Heat treatment after hot forming is recommended for achieving optimal corrosion behavior.

Cold Working of Incoloy 926 (UNS N08926/W.NR.1.4529)

  • (1) Like all austenitic chromium-nickel stainless steels, Incoloy 926 (N08926) alloy has a large work hardening rate, so it is necessary to select processing equipment. The cold-worked material should be in a solution heat-treated state, and intermediate annealing should be carried out when the amount of cold work is large. 
  • (2) If the amount of cold working is greater than 15%, the workpiece needs to be treated with a second solution.

Heat Treatment of Incoloy 926 (UNS N08926/W.NR.1.4529)

Solution annealing should take place at temperatures between 1,150 to -1,200 °C (2,102 to -2,192 °F) and preferably at 1,180 °C (2,156 °F). The retention time during annealing depends on the semi-finished product thickness and can be calculated as follows:

  • For thicknesses of d <= 10 mm (0.39 in), the retention time is t = d∙3 min/mm;
  • For thicknesses of d = 10 to 20 mm (0.39 in to 0.79 in), the retention time t = 30 min + (d – 10 mm)∙2 min/mm;
  • For thicknesses of d > 20 mm (0.79 in), the retention time t = 50 min + (d – 20 mm)∙1 min/mm.

The retention time starts with material temperature equalization; longer times are generally considerably less critical than retention times that are too short. Cooling down should be accelerated with water to achieve optimum properties. Fast air cooling can also be carried out at thicknesses of less than approx. 1.5 mm. The material must be placed in a furnace that has been heated up to the maximum annealing temperature before any heat treatment. For strip and wire products, the heat treatment can be performed in a continuous furnace at a speed and temperature that is adapted to the metal material thickness.

Pickling of incoloy 926 (UNS N08926/W.Nr.1.4529)

Before pickling in nitric-hydrofluoric acid mixtures, the oxide layers should be destroyed by abrasive blasting or fine grinding, or pre-treated in salt baths. The pickling baths used should be carefully monitored with regard to concentration and temperature.

Welding filler

2.4621, 2.4831, 2.4607, 2.4611
Possible welding methods include shielded metal arc welding, TIG welding, and plasma welding, in the same manner as with standard austenitic stainless steels. As welding consumables, Alloy 276 should be used. Preheating and post-welding heat treatment are not necessary.

Deoxidation and pickling of incoloy 926 (UNS N08926/W.Nr.1.4529)

  • (1) Incoloy 926 (N08926) alloy has stronger adhesion of surface oxides and weld slag around the weld than low alloy stainless steel. It is recommended to use Fine-grained abrasive belt or fine-grained grinding wheel for grinding. 
  • (2) Before pickling with HNO3/HF mixed acid for appropriate time and temperature, it must be carefully polished or salt bath pretreatment to break the oxide film.

Machining of incoloy 926 (UNS N08926/W.Nr.1.4529)

Incoloy 926 (N08926) alloy should be machined after heat treatment. Due to the work hardening of the material, it is advisable to use a lower cutting speed and re-entry than processing low alloy standard austenitic stainless steel Only when the knife is processed can it be turned under the hardened surface.

Test Methods of ASTM B677 UNS N08926 Seamless Pipe

  • NTD (Ultrasonic test, Eddy Current test) 
  • Mechanical Test (Tension Test, Flaring Test, Flattening Test, Hardness Test, Hydraulic test)
  • Metal Test (Metallographic Analysis, Impact Test-High/low temperature)
  • Chemical Analysis (Photoelectric Emission Spectroscopic)

Determine the chemical composition, mechanical, and other properties of the material as enumerated in this 

specification, in case of disagreement, in accordance with the following methods:  

Test ASTM Designation
Chemical analysis E 354
Tension E 8
Rounding procedure E 29

For purposes of determining compliance with the specified limits for requirements of the properties listed in the following table, an observed value or a calculated values shall be rounded as indicated, in accordance with the rounding method of Practice E 29:

Test Rounded Unit for Observed
or Calculated Value
Chemical composition and tolerances (when expressed in decimals) Nearest unit in the last right-hand place of figures of the specified limit. If two choces are possible, as when the digits dropped are exactly a 5 or a 5 followed only by zeros, choose the one ending in an even digit, with zero defined as an even digit.
Tensile strength, and yield strength Nearest 1000 psi (6.9 MPa)
Elongation Nearest 1%

Inspection Quality of UNS N08926 Seamless Pipe

Our factory are ISO 9001 and CE-PED approved manufacturer. We believe that the quality is the life of company. To provide quality product is the things we are doing.

  • PMI test to ensure the material quality;
  • Dimension controlling during fabricating and finished;
  • 100% Visual and surface examination;
  • NDT test (Eddy Current and Hydro Test);
  • Other requirement on request.

Inspection and Testing for UNS N08926 Seamless Pipe

Eddy Current Test Liquid Dye Penetrant Test Bending Test Impact Test
Hydrostatic Test Ultrasonic Test Flaring Test Intergranular Corrosion Test
Radiography Test (for welded pipe) Tensile Test Flattening Test Grain Size Test
Hardness Test Surface Roughness Dimension Examination Chemical Analysis
Positive Material Identification (PMI) Hardness Test Visual Checking Other test on requirement

Package of UNS N08926 Seamless Pipe

For the UNS N08926 seamless pipe, we commonly will pack them by waven bag and bundled by strong metal strap. For alloy steel tubing, we generally will pack them in free-fumigation wooden box. If you have special requirement, pls clarify it in the PO.

How To Order Alloy Steel Pipe?

When you want to get a quote or place an order to us, pls clear the information:

Product + Dimension + Material + Order Quantity

For example, you want to buy 2000mm UNS N08926 Pipe, Seamless, quality to ASTM B677, 26.7mm 4.5mm, beveled end, so the description would be:

ASTM B677-2016 UNS N08926 Seamless Pipe 26.7*4.5*2000mm

For the pipe quality, we will think it is ASME as they are the common grade in the market.
Please don’t hesitate to contact us if you have any question.
Do you accept cut-to-length orders for alloy steel pipes?
Yes for the alloy pipes we have in stock, cut to length is supported.
How can I trust you?
All of our alloy steel pipes are traceable to contract number and furnace number. For all alloy steel pipe, we will perform NDT and PMI testing prior to packaging.
We have over 15 years of experience supplying alloy steel tubes and fittings and have served over 200 customers. We have the experience to provide quality stainless steel tubing for your project.
Do you accept third party inspection?
Absolutely, yes.
We are experienced in third party inspections such as SGS, BV, Lloyd’s, Intertek, DNV, etc.
In fact, we think pre-shipment inspection will reduce disputes, which is a good way for both of us.
Do you accept customization?
Why not? We can manufacture products to customer specifications, including special sizes (sometimes based on specific quantities). Whether the material is alloy steel or a special alloy, we have extensive experience.
What’s Your Market?
We aim the global market, including but not limited to Argentina, Belgium, Brazil, Canada, Chile, Colombia, Costa Rica, Czech Republic, Denmark, Ecuador, Finland, France, Germany, Hungary, Ireland, Italy, Japan, Kazakhstan, Korea Mexico, Netherlands, Pakistan, Panama, Paraguay, Peru , Philippines, Poland, Russia, Spain, Sweden, Switzerland, Ukraine, Ukraine, United Kingdom, United States, Uruguay, Vietnam, etc.

China Alloy Steel Pipe Manufacturer offers ASTM B677-2016 UNS N08926 Seamless Pipe 26.7*4.5*2000mm.

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