A335 PIPE SPECIFICATIONS

A/SA335

1/4″ – 24″

Schedules 40 through 160, STD, XH and XXH

Scope

This specification covers nominal wall and minimum wall ferritic -steel pipe intended for high-temperature service. 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 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
Normalize and Temper ***** 1250 [675]
Subcritical Anneal (P5c only) ***** 1325 – 1375 [715 - 745]
P9 Full or Isothermal Anneal
Normalize and Temper ***** 1250 [675]
P11 Full or Isothermal Anneal
Normalize and Temper ***** 1200 [650]
P22 Full or Isothermal Anneal
Normalize and Temper ***** 1250 [675]
P91 Normalize and Temper 1900-1975 [1040 - 1080] 1350-1470 [730 - 800]
Quench and Temper 1900-1975 [1040 - 1080] 1350-1470 [730 - 800]

Chemical Requirements

Grade P-5 P-9 P-11 P-22 P-91 P-91 shall also include the following:
Element UNS Designation K41545 S50400 K11597 K21590 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
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
Phosphorous, max 0.025 0.025 0.025 0.025 0.020 Ni at 0.40 max
Sulfur, max 0.025 0.025 0.025 0.025 0.010 Al at 0.02 max
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
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
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

Tensile Requirements

Seamless
P-5 P-9 P-11 P-22 P-91 P91 shall not have a hardness not exceeding 250 HB/265 HV [25HRC].
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
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 and Flattening Test, Hardness Test, 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.
Notes for Hardness Test: P91 shall not have a hardness not exceeding 250 HB/265 HV [25HRC].
Notes for Bend Test: For pipe whose diameter exceeds NPS 25 and whose diameter to wall thickness ratio is 7.0 or less shall be subjected to the bend test instead of the flattening test.
Other pipe whose diameter equals or exceeds NPS 10 may be given the bend test in place of the flattening test subject to the approval of the purchaser.
The bend test specimens shall be bent at room temperature through 180 without cracking on the outside of the bent portion.
The inside diameter of the bend shall be 1 inch [25 mm].
Hydrostatic Test Each length of pipe shall be Hydro tested, at option of manufacture, nondestructive electric testing can be used.

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
Marking to indicate the test method(s)
Hydrostatic Nondestructive Marking
YES NO Test Pressure
NO YES NDE
NO NO NH
YES YES Test Pressure/NDE
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
Pipe that has been weld repaired shall be marked “WR”.

Reference Documents

  • ASTM A999/A 999M Specification for General requirements for Alloy and 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 Pipe
Grade P5, P9, P11, P22, P91
Manufacture 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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