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Everything You need to Know about

ASTM B444

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Overview

ASTM B444 is a very commonly used standard for nickel alloy seamless pipes. The standard mainly includes Inconel 625 (UNS N) and two other materials. The main products are seamless pipe & tube. In this article, we will detail the important requirements mentioned in ASTM B444. This will allow you to better control the quality when ordering.

Product Properties

Products in ASTM B444

Inconel 625
Seamless Pipe & Tube

ASTM B444 mainly specifies the technical requirements for seamless pipe & tube. Among them, the materials with an outer diameter of 127mm or less are defined as seamless tubes. Materials with an outer diameter of 127mm or more are seamless pipes.

Mechanical Properties

Mechanical Properties of Rod and Bar Condition and Diameter or Distance Between Parallel
Surfaces, in. (mm) Tensile Strength
min, ksi (MPa) Yield Strength (0.2% offset)
min. ksi (MPa) Elongation in 2 in. or 50
mm (or 4D), min, % Inconel 625 (UNS N) Grade 1 (annealed) 120 (827) 60 (414) 30 Grade 2 (solution annealed) 100 (690) 40 (276) 30 UNS N All (solution annealed) 96 (660) 39 (270) 30 UNS N All (solution annealed) 85 (586) 35 (241) 30

Delivery State

In ASTM B444, UNS N and UNS N are only specified for delivery in solution treated state.

For Inconel 625 (UNS N), the standard specifies the following two states:

Grade 1 (annealed): Grade 1 is the annealed state, which is stronger and suitable for use at temperatures up to °F (593°C). In most cases, Inconel 625 will be used at this temperature. Therefore, grade 1 is the default delivery state for the Inconel 625 seamless pipe & tube.

Are you interested in learning more about inconel 625 tubing? Contact us today to secure an expert consultation!

Grade 2 (solution annealed): Grade 2 requires the material to be delivered in a solution annealed state. When the material is used above °F (593°C). The Grade 2 state helps to improve the creep properties and fatigue properties of the alloy. Therefore, if you need Inconel 625 seamless pipe & tube to be used at higher temperature, you should choose grade 2.

Other Information

Dimension

For small-diameter tube and light-wall tube, the standard additionally specifies tolerances for outer diameter, wall thickness and length. For other seamless pipes & tubes, tolerances should refer to ASTM B829.

Permissible Variations for Outside Diameter and Wall Thickness of Seamless Cold-Worked Pipe and Tube Nominal Outside Diameter,
in. (mm) Permissible Variations Thickness of Specified Minimum Wall, % Outside Diameter,
in. (mm) Thickness of
Specified
Nominal Wall, % Plus Minus Plus Minus Plus Minus Over 0.400 (10) to 5/8 (16), excl 0.005 (0.13) 0.005 (0.13) 15.0 15.0 30 0 5/8 (16) to 1 1/2 (38), incl 0. (0.19) 0. (0.19) 10.0 10.0 22 0 Over 1 1/2 (38) to 3 (76), incl 0.010 (0.25) 0.010 (0.25) 10.0 10.0 22 0 Over 3 (76) to 4 1/2 (114), incl 0.015 (0.38) 0.015 (0.38) 10.0 10.0 22 0 Over 4 1/2 (114) to 6 (152), incl 0.020 (0.51) 0.020 (0.51) 12.5 12.5 28 0 Over 6 (152) to 6 5/8 (168), incl 0.025 (0.64) 0.025 (0.64) 12.5 12.5 28 0 Over 6 5/8 (168) to 8 5/8 (219), incl 0.031 (0.79) 0.031 (0.79) 12.5 12.5 28 0 Over 8.625 (219) to 14 (356), incl 0.062 (1.57) 0.031 (0.79) 15.0 12.5 30.0 0.0 Over 14 (356) to 24 (610), incl 0.125 (3.18) 0.031 (0.79) 15.0 12.5 30.0 0.0 Permissible Variations for Outside Diameter and Wall Thickness of Hot-Finished Tube Nominal Outsider Diameter,
in. (mm) Permissible Variations Outside Diameter or Inside
Diameter, in. (mm) % of Thickness of Specified
Nominal Wall % of Thickness of Specific
Minimum Wall + - + - + - 3/4 (19) to 1 1/2 (38), incl 0.015 (0.4) 0.031 (0.8) 12.5 12.5 28.5 0 Over 1 1/2 (38.1) to 4 (102), incl 0.031 (0.8) 0.031 (0.8) 12.5 12.5 28.5 0 Over 4 (102) to 9 1/4 (235), incl 0.062 (1.6) 0.031 (0.8) 12.5 12.5 28.5 0 Permissible Variations for Outside Diameter and Wall Thickness of Seamless Hot-Worked Pipe Nominal Outsider Diameter,
in. (mm) Permissible Variations Outside Diameter,
in. (mm) Thickness of Specified
Nominal Wall, % Thickness of Specified
Minimal Wall, % Plus Minus Plus Minus Plus Minus 1 (25) to 1.900 (48), incl 0.015 (0.40) 0.031 (0.79) 16.0 12.5 28.5 0 over 1.900 (48) to 4 1/2 (114), incl 0.031 (0.79) 0.031 (0.79) 16.0 12.5 28.5 0 over 4 1/2 (114) to 6 1/2 (165), incl 0.047 (1.2) 0.047 (1.2) 16.0 12.5 28.5 0 over 6 1/2 (165) to 9 1/4 (235), incl 0.062 (1.6) 0.062 (1.6) 16.0 12.5 28.5 0 Permissible Variations in Length Outside Diameter, in. (mm) Cut Length, in. (mm) Over Under Under 2 (50.8) 1/8 (3.2) 0 2 (50.8) and over 3/16 (4.8) 0 Permissible Variations for Small-Diameter and Light-Wall Tube (Converter Sizes) Specified Outside Diameter, in. (mm) Outside Diameter Inside Diameter Wall Thickness, % Plus Minus, in.
(mm) Plus Minus Plus Minus Under 3/32 (2.4) 0.002 (0.05) 0 0 0.002 (0.05) 10 10 3/32 to 3/16 (2.4 to 4.8), excl 0.003 (0.08) 0 0 0.003 (0.08) 10 10 3/1 6 to 1/2 (4.8 to 12.7), excl 0.004 (0.10) 0 0 0.004 (0.10) 10 10 1/2 to 1 1/4 (12.7 to 31.8), incl 0.005 (0.13) 0 0 0.005 (0.13) 10 10 Tolerances on Cut Lengths of Light-Wall Tube Length, ft (m) Tube Size, in. (mm) Permissible Variations, in. (mm) Over Under Under 1 (0.30) up to 1.250 (31.8), incl 1/32 (0.8) 0 (0) 1 to 4 (0.30 to 1.22), incl up to 1.250 (31.8), incl 1/16 (1.6) 0 (0) Over 4 to 10 (1.22 to 3.0), incl up to 1.250 (31.8), incl 3/32 (2.4) 0 (0) Over 10 (3.0) up to 1.250 (31.8), incl 3/16 (4.8) 0 (0)

Hydrostatic Test

Each pipe or tube with an outside diameter 3mm and larger and with wall thickness of 0.38 mm and over shall be tested in accordance with Specification ASTM B829.

For Inconel 625, the test pressure for grade 1 is 30,000 psi (207 MPa). Grade 2 is tested to 25,000 psi (172 MPa).

Test pressures for UNS N and UNS N are 24,000 psi (165 MPa) and 21,000 psi (145 MPa), respectively.

The results of the hydrostatic test shall be reflected in the material test certificate.

Certification

Supplier should issue material test certificate corresponding to the material before shipment. The certificate should include supplier information, customer information, product form and state, heat number, chemical composition, mechanical properties, smelting method, hydrostatic test result and other necessary information.

Conclusion

ASTM B444 is mainly used for seamless pipe & tube of nickel-chromium-molybdenum-niobium alloy and nickel-chromium-molybdenum-silicon alloy. Among them, Inconel 625 seamless pipe & tube is the most commonly used material in the standard. Suppliers shall manufacture this material strictly in accordance with ASTM B444.

We produce Inconel 625 seamless pipe & tube according to ASTM B444 standard by default. If you have corresponding needs, please do not hesitate to contact us.

Contact us to discuss your requirements of astm a511 stainless steel hollow bar wholesale. Our experienced sales team can help you identify the options that best suit your needs.