ASTM A335 / ASME SA335
ASTM A335 / A335M – Standard Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service
This specification covers seamless ferritic alloy-steel pipe for high-temperature service. The pipe shall be suitable for bending, flanging (vanstoning), and similar forming operations, and for fusion welding. Grade P2 and P12 steel pipes shall be made by coarse-grain melting practice. The steel material shall conform to chemical composition, tensile property, and hardness requirements. Each length of pipe shall be subjected to the hydrostatic test. Also, each pipe shall be examined by a non-destructive examination method in accordance to the required practices. The range of pipe sizes that may be examined by each method shall be subjected to the limitations in the scope of the respective practices. The different mechanical test requirements for pipes, namely, transverse or longitudinal tension test, flattening test, and hardness or bend test are presented.
- Ferritic steels in this specification are defined as low- and intermediate-alloy steels containing up to and including 10 % chromium.
- Main Steel Pipe Grades – P2, P5, P9, P11, P12, P22, P23, P91, P92
Ordering Information for Alloy Steel Pipes, as per ASTM A335
- Orders for material under this specification should include the following, as required, to describe the desired material adequately:
- Quantity (feet, centimetres, or number of lengths),
- Name of material (seamless alloy steel pipe),
- Manufacture (hot-finished or cold-drawn),
- Size (NPS or outside diameter and schedule number or average wall thickness),
- Length (specific or random),
- End finish (Ends Section of Specification A999/A 999M),
- Test report required (Certification Section of Specifi- cation AA 999/A 999M),
- Specification designation,
- Special requirements or any supplementary requirements selected, or both.
Materials and Manufacture
- Pipe may be either hot finished or cold drawn with the finishing treatment
- Grade P2 and P12 – The steel shall be made by coarse- grain melting practice. Specific limits, if any, on grain size or deoxidation practice shall be a matter of agreement between the manufacturer and purchaser.
Heat Treatment of Alloy Steel Pipes
- All pipe of grades except P5c, P91, P92, and P122 as provided, shall be reheated and furnished in the full-annealed, isothermal annealed, or normalized and tempered condition. If furnished in the normalized and tempered condition, the minimum tempering temperature for Grades P5, P5b, P9, P21, and P22 shall be 1250°F [675°C], the minimum tempering temperature for Grades P1, P2, P11, P12, and P 15 shall be 1200°F [650°C].
- It is recommended that the temperature for tempering should be at least 100°F [50°C] above the intended service temperature; consequently, the purchaser should advise the manufacturer if the service temperature is to be over 1100°F [600°C].
- Pipe of Grades P1, P2, and P12, either hot finished or cold drawn, may be given a final heat treatment at 1200°F [650°C] to 1300°F [705°C] instead of heat treatments
- All pipe of Grades P5c shall be given a final heat treatment in the range from 1325°F [715°C] to 1375°F [745°C].
- Certain of the ferritic steels covered by this specification will harden if cooled rapidly from above their critical temperature. Some will air harden, that is, become hardened to an undesirable degree when cooled in air from high temperatures. Therefore, operations involving heating such steels above their critical temperatures, such as welding, flanging, and hot bending, should be followed by suitable heat treatment.
- Grade T92 shall be normalized at 1900°F [1040°C] minimum and tempered at 1350°F [730°C] minimum as a final heat treatment.
- Grade P122 shall be normalized at 1900°F [1040°C] minimum, and tempered at 1350°F [730°C] minimum as a final heat treatment.
- Except when Supplementary Requirement S7 is speci- fied by the purchaser, Grade P91 shall be normalized at 1900°F [1040°C] minimum, and tempered at 1350°F [730°C] mini- mum as a final heat treatment. Alternatively, liquid quenching and tempering is allowed for thicknesses above 3 in. when mutually agreed upon between the manufacturer and the purchaser. In this case the pipe shall be quenched from 1900°F [1040°C] minimum and tempered at 1350°F [730°C] minimum as final heat treatment.
ASTM A335 Chemical Composition
|Grade||ASTM A335 Chemical Composition|
|C||Mn||P max||S max||Si||Cr||Mo||V||N||Others|
|P91||0.08-0.12||0.3-0.6||0.02||0.01||0.2-0.5||8.0-9.5||0.85-1.05||0.18-0.25||0.03-0.07||Ni(≤0.4), Al(≤0.02), Cb(0.06-0.1)|
|P92||0.07-0.13||0.3-0.6||0.02||0.01||≤0.50||8.5-9.5||0.3-0.6||0.15-0.25||0.03-0.07||Ni(≤0.4), AL(≤0.02), Cb(0.04-0.09)|
|P122||0.07-0.14||≤0.7||0.02||0.01||≤0.50||10.0-11.5||0.25-0.6||0.15-0.3||0.04-0.1||Ni(≤0.5), Al(≤0.02), Ti(≤0.01)|
|W(1.5-2.5), Cu(0.3-1.7), Zr(≤0.01)|
- New designation established in accordance with Practice E 527 and SAE J1086, Practice for Numbering Metals and Alloys (UNS).
- Grade P5c shall have a titanium content of not less than 4 times the carbon content and not more than 0.70 %; or a columbium content of 8 to 10 times the carbon content.
Mechanical Properties for ASTM A335 Pipes
|ASTM A335 Mechanical Properties|
|Grade||Tensile Strength(MPa)||Yield Strength(MPa)||Elongation(%)|
Size Tolerances for ASTM A335
Outside Diameter Tolerance
|ASTM A450||Hot rolled||Outside Diameter(mm)||Tolerance(mm)|
|ASTM A530, ASTM A335||NPS||Outside Diameter(inch)||Tolerance(mm)|
|4＜OD≤8||+1.59 / -0.79|
|8＜OD≤12||+2.38 / -0.79|
Thickness Tolerance for ASTM A335 Pipes
|ASTM A450||Hot rolled||Outside Diameter(mm)||Tolerance (%)|
|OD≤101.6,WT≤2.4||+40 / -0|
|OD≤101.6,2.4＜WT≤3.8||+35 / -0|
|OD≤101.6,3.8＜WT≤4.6||+33 / -0|
|OD≤101.6,4.6＜WT||+28 / -0|
|101.6＜OD,2.4＜WT≤3.8||+35 / -0|
|101.6＜OD,3.8＜WT≤4.6||+33 / -0|
|101.6＜OD,4.6＜WT||+28 / -0|
|Cold Drawn||OD≤38.1||+20 / -0|
|OD＞38.1||+22 / -0|
|ASTM A530||NPS||Outside Diameter(inch)||Tolerance (%)|
|1/8≤OD≤2-1/2||+22 / -12.5|
|3≤OD≤18,WT/OD≤5%||+22.5 / -12.5|
|3≤OD≤18,WT/OD＞5%||+15 / -12.5|
|20≤OD,WT/OD≤5%||+22.5 / -12.5|
|20≤OD,WT/OD＞5%||+15 / -12.5|
- Each length of pipe shall be subjected to the hydro-static test,
- Unless otherwise specified in the purchase order, each length of pipe shall, at the option of the manufacturer, be subjected to the nondestructive electric test in lieu of the hydrostatic test.
- When specified by the purchaser, pipe shall be fur- nished without hydrostatic test and without nondestructive examination.
- When specified by the purchaser, pipe shall be fur- nished with both the hydrostatic test and a nondestructive examination having been performed.
Mechanical Tests Required
- 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 1 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.
- The term “lot” applies to all pipe of the same nominal size and wall thickness (or schedule) which is produced from the same heat of steel and subjected to the same finishing treatment in a continuous furnace; when final heat treatment is in a batch-type furnace, the lot shall include only that pipe which is heat treated in the same furnace charge.
- For pipe of Grade P122, Brinell, Vickers, or Rock- well hardness tests shall be made on a specimen from each lot.
- 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 in. [25 mm].
- Test specimens for the bend test shall be cut from one end of the pipe and, unless otherwise specified, shall be taken in a transverse direction. One test specimen shall be taken as close to the outer surface as possible and another from as close to the inner surface as possible. The specimens shall be either 1⁄2 by 1⁄2 in. [12.5 by 12.5 mm] in section or 1 by 1⁄2 in. [25 by 12.5 mm] in section with the corners rounded to a radius not over 1⁄16 in. [1.6 mm] and need not exceed 6 in. [150 mm] in length. The side of the samples placed in tension during the bend shall be the side closest to the inner and outer surface of the pipe, respectively.