In ASTM A213, in addition to the requirements for tensile properties and hardness, the following tests are also required: Flattening Test and Bend Test.
ASTM A335 P22 (ASME SA335 P22) is a high-temperature service seamless chromium-molybdenum alloy steel pipe, widely used in boilers, superheaters, and heat exchangers.
It contains 1.90% to 2.60% chromium and 0.87% to 1.13% molybdenum, has excellent heat resistance, and is also suitable for bending, flanging, or similar forming operations.
UNS number: K21590.
ASTM A335 is the standard specification for seamless ferritic alloy-steel pipes intended for high-temperature service. It is widely used in boilers, superheaters, heat exchangers, and other applications that operate under high-temperature and high-pressure conditions. In addition to Grade P22, other common alloy grades include P5 (UNS K41545), P9 (UNS K90941), P11 (UNS K11597), and P91 (UNS P90901).
Manufacturer and Condition
ASTM A335 P22 steel pipes shall be made by the seamless process and shall be either hot-finished or cold-drawn with the finishing treatment.
Seamless steel pipes are pipes without welds, which provides P22 steel pipes with higher stability and reliability in high-temperature and high-pressure environments.
Heat Treatment
P22 steel pipes shall be reheated and heat-treated by either full annealing, isothermal annealing, or normalizing and tempering.
| Grade | Heat treat type | Subcritical Annealing or Temperature |
| ASTM A335 P22 | full or isothermal anneal | — |
| normalize and temper | 1250 ℉ [675 ℃] min |
Chromium (Cr) and molybdenum (Mo) are key alloying elements in P22 steel, improving high-temperature strength, oxidation resistance, and durability. The specific chemical composition is shown below:
| Grade | Composition, % | ||||||
| C | Mn | P | S | Si | Cr | Mo | |
| P22 | 0.05 ~ 0.15 | 0.30 ~ 0.60 | 0.025 max | 0.025 max | 0.50 max | 1.90 ~ 2.60 | 0.87 ~ 1.13 |
The mechanical property tests of P22 shall be carried out in accordance with the relevant requirements of ASTM A999.
Tensile Properties
| Grade | ASTM A335 P22 | |
| Tensile strength, min | 60 ksi [415 MPa] | |
| Yield strength, min | 30 ksi [205 MPa] | |
| Elongation in 2 in. or 50 mm (or 4D), min | Longitudinal | Transverse |
| Basic minimum elongation for wall 5/16 in [8 mm] and over in thickness, strip tests, and for all small sizes tested in full section | 30% | 20% |
| When a standard round 2 in or 50 mm gage length or proportionally smaller size specimen with the gage length equal to 4D (4 times the diameter) is used | 22% | 14% |
| For strip tests a deduction for each 1/32 in [0.8 mm] decrease in wall thickness below 1/32 in. [8 mm] from the basic minimum elongation of the following percentage points shall be made | 1.50% | 1.00% |
Hardness Properties
The ASTM A335 standard does not specify specific hardness requirements for P22 steel pipes.
Other Test Items
Diameter Tolerance
For pipe ordered by NPS [DN] or outside diameter, variations in outside diameter shall not exceed the requirements shown in the table below:
| NPS [DN] Designator | Permissible Variations | |
| in. | mm | |
| 1/8 to 1 1/2 [6 to 40], inch. | ±1/64 [0.015] | ±0.40 |
| Over 1 1/2 to 4 [40 to 100], inch. | ±1/32 [0.031] | ±0.79 |
| Over 4 to 8 [100 to 200], inch. | -1/32 - +1/16 [-0.031 - +0.062] | -0.79 - +1.59 |
| Over 8 to 12 [200 to 300], inch. | -1/32 - +3/32 [-0.031 - 0.093] | -0.79 - +2.38 |
| Over 12 [300] | ±1 % of specified outside diameter | |
For pipe ordered to inside diameter, the inside diameter shall not vary more than 1% from the specified inside diameter.
Wall Thickness Tolerance
In addition to the implicit limitation of wall thickness for pipe imposed by the limitation on weight in ASTM A999, the wall thickness for pipe at any point shall be within the tolerances specified in the table below:
| NPS [DN] Designator | Tolerance |
| 1/8 to 2 1/2 [6 to 65] incl. all t/D ratios | -12.5 % ~ +20.0 % |
| Above 2 1/2 [65], t/D ≤ 5% | -12.5 % ~ +22.5 % |
| Above 2 1/2, t/D ＞ 5% | -12.5 % ~ +15.0 % |
| ASME | ASTM | EN | DIN | JIS |
| ASME SA335 P22 | ASTM A213 T22 | DIN 10216-2 10CrMo9-10 | DIN 17175 10CrMo9-10 | JIS G 3458 STPA25 |
Material: ASTM A335 P22 seamless steel pipes and fittings;
Size: 1/8" to 24", or customized according to your requirements;
Length: Random length or cut to order;
Packaging: Black coating, beveled ends, pipe end protectors, wooden crates, etc.
Support: IBR certification, TPI inspection, MTC, cutting, processing, and customization;
MOQ: 1 m;
Payment Terms: T/T or L/C;
Price: Contact us for the latest T11 steel pipe prices;
