A335 Pipe Specifications
NPS 1/4″ – 24″
Schedules 40 through 160, STD, XH and XXH
Scope
This specification covers nominal wall and minimum wall seamless ferritic alloy-steel pipe intended for high-temperature service. ASTM A335 pipe ordered to this specification shall be suitable for fusion welding, bending, flanging (vanstoning), and similar forming operations.
Material & Manufacture
Pipe may be either hot finished or cold drawn with the finishing heat treatment noted below.
Heat Treatment Requirements
P5, P9, P11, and P22 | |||
Grade | Heat Treatment Type | Normalizing Temperature Range F [C] | Subcritical Annealing or Tempering Temperature Range F [C] |
P5 (b,c) | Full or Isothermal Anneal, or | ||
Normalize and Temper | ***** | 1250 [675] | |
Subcritical Anneal (P5c only) | ***** | 1325 – 1375 [715 – 745] | |
P9 | Full or Isothermal Anneal, or | ||
Normalize and Temper | ***** | 1250 [675] | |
P11 | Full or Isothermal Anneal, or | ||
Normalize and Temper | ***** | 1200 [650] | |
P22 | Full or Isothermal Anneal, or | ||
Normalize and Temper | ***** | 1250 [675] | |
P91 (type 1 and 2) | Normalize and Temper, or | 1900-1975 [1040 – 1080] | 1350-1470 [730 – 800] |
Quench and Temper | 1900-1975 [1040 – 1080] | 1350-1470 [730 – 800] |
Chemical Requirements
Grade | P5 | P9 | P11 | P22 | P91 (type 1) | P91 type 1 shall also include the following: | P91 (type 2) | P91 type 2 shall also include the following | P91 type 2 continued | ||
Element | UNS | K41545 | K90941 | K11597 | K21590 | K91560 | K91560 | ||||
Carbon | 0.15 max | 0.15 max | 0.05 – 0.15 | 0.05 – 0.15 | 0.08 – 0.12 | V at 0.18 – 0.25 | Heat: 0.08 – 0.12 Product: 0.07 – 0.13 |
V (heat) at 0.18 – 0.25 V (product) at 0.16 – 0.27 |
N / Al ration ≥ 4.0 | ||
Manganese | 0.30 – 0.60 | 0.30 – 0.60 | 0.30 – 0.60 | 0.30 – 0.60 | 0.30 – 0.60 | N at 0.030 – 0.070 | 0.30 – 0.50D | N at 0.035 – 0.070D | Sn at 0.01 maxD | ||
Phosphorous, max | 0.025 | 0.025 | 0.025 | 0.025 | 0.020 | Ni at 0.40 max | 0.20D | Ni at 0.02 maxD | Sb at 0.003 maxD | ||
Sulfur, max | 0.025 | 0.025 | 0.025 | 0.025 | 0.010 | Al at 0.02 max | 0.005D | Al at 0.02 maxD | As at 0.010 maxD | ||
Silicon | 0.50 max | 0.25 – 1.00 | 0.50 – 1.00 | 0.50 max | 0.20 -0.50 | Cb at 0.06 – 0.10 | 0.20 – 0.40D | Cb (heat) at 0.06 – 0.1 Cb (product) at 0.05 – 0.11 |
B at 0.001 maxD | ||
Chromium | 4.00 – 6.00 | 8.00 – 10.00 | 1.00 – 1.50 | 1.90 – 2.60 | 8.00 – 9.50 | Ti at 0.01 max | 8.00 – 9.50D | Ti at 0.01 maxD | W at 0.05 maxD | ||
Molybdenum | 0.45 -0.65 | 0.90 – 1.10 | 0.44 – 0.65 | 0.87 – 1.13 | 0.85 – 1.05 | Zr at 0.01 max | Heat: 0.85 – 1.05 Product: 0.80 – 1.05 |
Zr at 0.01 maxD | Cu at 0.10 maxD | ||
DApplies to both heat and product analyses. |
Tensile Requirements
Seamless | ||||||||
P5 | P9 | P11 | P22 | P91 (1, 2) | P91 type 1 and 2 shall have a hardness within the range of 190 to 250 [HBW] or 196 to 265 [HV] or 91 HRBW to 25 HRC. | |||
Tensile Strength, min., psi | ||||||||
ksi | 60 | 60 | 60 | 60 | 85 | |||
MPa | 415 | 415 | 415 | 415 | 585 | |||
Yield Strength, min., psi | ||||||||
ksi | 30 | 30 | 30 | 30 | 60 | |||
MPa | 205 | 205 | 205 | 205 | 415 |
Permissible Variation in Wall Thickness
NPS [DN] Designator | Tolerance, % from Specified | |||
Over | Under | |||
1/8 to 2 1/2 [6 to 65] incl., all t/D ratios | 20.0% | 12.5% | ||
Above 2 1/2 [65], t/D < or = 5% | 22.5% | 12.5% | ||
Above 2 1/2 [65], t/D > 5% | 15.0% | 12.5% | ||
(t = Specified Wall Thickness; D = Specified Outside Diameter) |
Elongation Requirements
Calculated Minimum Elongation Values | |||||
Elongation in 2 in. or 50 mm, min % | |||||
Wall Thickness | P5, P9, P11, P22 | P91 (type 1 and 2) | |||
in. | mm | Longitudinal | Transverse | Longitudinal | |
5/16 (0.312) | 8 | 30 | 20 | 20 | |
9/32 (0.281) | 7.2 | 28 | 19 | 19 | |
1/4 (0.250) | 6.4 | 27 | 18 | 18 | |
7/32 (0.219) | 5.6 | 26 | 17 | ||
3/16 (0.188) | 4.8 | 24 | 16 | ||
5/32 (0.156) | 4 | 22 | 15 | ||
7/8 (0.125) | 3.2 | 21 | 14 | ||
3/32 (0.094) | 2.4 | 20 | 13 | ||
1/18 (0.062) | 1.6 | 18 | 12 |
Permissible Variations in Outside Diameter
Outside Diameter at any point shall not vary from standard specified more than:
NPS [DN] Designator | Over | Under | ||
in. | mm | in. | mm | |
1/8 to 1 1/2 [6 to 40], incl. | 1/64 (0.015) | 0.40 | 1/64 (0.015) | 0.40 |
Over 1 1/2 to 4 [40 to 100], incl. | 1/32 (0.031) | 0.79 | 1/32 (0.031) | 0.79 |
Over 4 to 8 [100 to 200], incl. | 1/16 (0.062) | 1.59 | 1/32 (0.031) | 0.79 |
Over 8 to 12 [200 to 300], incl. | 3/32 (0.093) | 2.38 | 1/32 (0.031) | 0.79 |
Over 12 [300] | +/- 1% of the specified outside diameter |
Mechanical Tests Specified
Transverse or Longitudinal Tension Test, Hardness Test, and Flattening or Bend Test. | ||||||||
For material heat treated in a batch-type furnace, tests shall be made on 5% of the pipe from each treated lot. For small lots, at least one pipe shall be tested. | ||||||||
For material heat treated by the continuous process, tests shall be made on a sufficient number of pipe to constitute 5% of the lot, but in no case less than 2 pipe. | ||||||||
Unless otherwise specified, the flattening test or bend test shall be chosen at the manufacturer’s option. |
See our full list of pipe testing services.
Required Markings on Each Length
(On Tags attached to each Bundle in case of Bundled Pipe) Markings will adhere to prescribed specifications in A 999/A999M and be: Rolled, Stamped, or Stenciled (Mfrs. Option)
In addition, markings will include: | ||||||||||||||||||||||||||
Length of pipe |
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Schedule Number | ||||||||||||||||||||||||||
Heat Number or Manufacturer’s number by which heat can be identified | ||||||||||||||||||||||||||
An Additional Symbol “S” if the pipe conforms to any Supplementary Requirements | ||||||||||||||||||||||||||
S1 – Product Analysis | ||||||||||||||||||||||||||
S2 – Transverse Tension Test | ||||||||||||||||||||||||||
S3 – Flattening Test | ||||||||||||||||||||||||||
S4 – Metal Structure and Etching Tests | ||||||||||||||||||||||||||
S5 – Photomicrographs | ||||||||||||||||||||||||||
S6 – Photomicrographs for Individual Pieces | ||||||||||||||||||||||||||
S7 – Alternative Heat Treatment – Grade P91 (type 1 and 2) |
Reference Documents
- ASTM A999/A 999M Specification for General requirements for Alloy and Stainless Steel Pipe.
- ASTM E 213 Practice for Ultrasonic Examination of metal Pipe and Tubing
- ASTM E 309 Practice for Eddy-Current Examination of Steel Tubular Products Using Magnetic Saturation
- ASTM E 381 Method of Macroetch testing Steel Bars, Billets, Blooms, and Forgings
- ASTM E 570 Practice for Flux Leakage Examination of Ferromagnetic Steel Tubular Products
- ASME B26.10M Welded and Seamless Wrought Steel Pipe
Ordering Information
Orders for material under this specification should include the following, as required, to describe the desired material adequately:
Quantity | Feet, meters, or number of lengths |
Name of material | Seamless Alloy Steel Pipe |
Grade | P5, P9, P11, P22, P91 (type 1 or 2) |
Manufacturer | Hot-finished or cold-drawn |
Size using one of the following: | |
NPS and Schedule Number | |
Outside Diameter and Nominal Wall Thickness | |
Outside Diameter and Minimum Wall Thickness | |
Inside Diameter and Nominal Wall Thickness | |
Inside Diameter and Minimum Wall Thickness | |
Length | Specific or Random |
End Finish |
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