ASME SA 335 P22 Pipes ASTM A335 P22 Seamless Pipe,2.25Cr-1Mo Pipe
We are a professional A335 P22 Pipe, Chrome Moly Seamless steel pipe supplier and exporter in China.ASTM A335/ASME SA335 P22 Alloy Steel Seamless Pipe, P22 material, A335 Chrome Moly Alloy Pipe Gr. P22, P22 Seamless Ferritic Alloy-Steel Pipe, ASME SA335 Grade P22 Alloy Steel Seamless Pipe, ASTM A335/ASME SA335 P22 Alloy Steel Pipe Manufacturer in China
ASTM A335 Grade P22 is a 2¼Cr-1Mo chromium-molybdenum alloy steel, well known for its excellent creep strength, oxidation resistance, and long-term thermal stability.
P22 pipes are widely used in boilers, superheaters, steam pipelines, heaters, and pressure vessels, where reliable performance at elevated temperatures is critical.
Product Scope – ASTM A335 P22 Pipes
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Seamless alloy steel pipes
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Hot-finished or cold-drawn
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Thick-wall pressure pipes
Outside Diameter: ½” – 48″
Wall Thickness: SCH 10, SCH 40, SCH 80, SCH 160, XXS
Length: Random, double random, or cut length
ASTM A335 Gr P22 Pipe can be used as starting material to produce A234 WP22 Pipe fittings,and match with A182 F22 flanges,and A182 F22 forged fittings
ASTM A335 2024 / A335M (Download ASTM A335 2024 standard PDF)
Standard Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service
The most commonly used P grades in the power generation industry and petro-chemical plants are P11, P22 & P91.
ASTM A335 P22 is one of the grade in ASTM A335/A335M standard, for 2.25Cr-1Mo boiler and superheater with chromium molybdenum high temperature ferritic steel.
A335 P22 Pipe is mainly used in steam pipeline, 300 600MW large capacity power plant boiler tube wall temperature are less than 580 of the superheater and the tube wall temperature are less than 540 of the wall and the header, A335 P22 has been widely used in the United States, Japan and Europe, has a long history in power plant operation that is a mature steel stable performance, good process performance.
ASTM A335 P22 Pipe also called 2 ¼ Chrome OR UNS K21590,
Material: P22, K21590
Equivalent Material: T22, 10CrMo910, 10CrMo9-10, 1.7380, 11CrMo9-10, 1.7383
ASTM A335/SA335 Grade P22 Alloy Steel Seamless Pipes are with chromium, molybdenum, and sometimes vanadium. Chromium, or chrome, improves high-temperature strength, increases oxidation resistance and raises the tensile, yield and hardness at room temperatures. Molybdenum increases the strength, elastic limit, resistance to wear, impact qualities and hardenability. It increases the resistance to softening, restrains grain growth and makes chromium steel less susceptible to embrittlement.
ASTM A335 P22 Pipe Inspection and Test:
Chemical Composition Inspection, Mechanical Properties Test(Tensile Strength,Yield Strength, Elongation, Flaring, Flattening, Bending, Hardness, Impact Test), Surface and Dimension Test,No-destructive Test, Hydrostatic Test.
A335 P22 Pipe Chemical composition
| C, % | Mn, % | P, % | S, % | Si, % | Cr, % | Mo, % |
| 0.015 max | 0.30-0.61 | 0.025 max | 0.025 max | 0.50 max | 1.90-2.60 | 0.87-1.13 |
A335 P22 Pipes Mechanical Properties :
| Tensile Strength, MPa | Yield Strength, MPa | Elongation, % |
| 415 min | 205 min | 30 min |
ASTM A335 P22 Pipe WALL THICKNESS Tolerance
The tolerances in WT, in %, from specified are:
- 1/8 to 2 1/2 [6 to 65] incl., all t/D ratios: over 20%, under 12.5%
- Above 2 1/2 [65], t/D < or = 5%: over 22.5%, under 12.5%
- Above 2 1/2 [65], t/D > 5%: over 15%, under 12.5%
t = Specified Wall Thickness; D = Specified Outside Diameter)
A335 P22 PIPE TESTING REQUIREMENTS
- Transverse/longitudinal: tension and flattening, hardness, bend tests- for material which has been heat-treated in batch furnaces, these tests shall be made on the 5% of the pipes from each heat lot number. For smaller lots, one pipe at a minimum has to be tested
- Hydro testing: shall be applied to every length of pipe
- The non-destructive electric test is optional
How to order our A335 P22 Seamless Pipes?
ASTM A213 T22 tube vs ASTM A335 P22 Pipes
Although T22 and P22 share similar chemical composition (2.25Cr-1Mo alloy steel), they are not interchangeable because they are designed for different product forms, applications, and codes.
Standard & Product Type
| Item | ASTM A213 T22 | ASTM A335 P22 |
| ASTM Standard | ASTM A213 / ASME SA213 | ASTM A335 / ASME SA335 |
| Product Type | Tube | Pipe |
| Manufacturing | Seamless | Seamless |
| Typical OD | Small / medium | Medium / large |
| Dimensional Standard | ASTM A213 / A450 | ASME B36.10 |
Key difference:
- T22 = tubing standard
- P22 = piping standard
Typical Applications
| Application | T22 Tube | P22 Pipe |
| Boilers | ✔✔✔ | ✔ |
| Superheaters | ✔✔✔ | ✔ |
| Reheaters | ✔✔✔ | ✔ |
| Heat exchangers | ✔✔✔ | ✖ |
| Steam pipelines | ✖ | ✔✔✔ |
| High-pressure piping | ✖ | ✔✔✔ |
| Power plants | ✔✔ | ✔✔✔ |
Summary:
- T22 is mainly for heat transfer equipment
- P22 is mainly for pressure piping systems
Size & Thickness Range
| Aspect | T22 Tube | P22 Pipe |
| OD Range | Small (typically ≤ 114.3 mm) | Large (½”–48″) |
| Wall Thickness | Thin to medium | Medium to very thick |
| Schedule System | Not schedule-based | Schedule-based (SCH 40, 80, etc.) |
Chemical Composition (Very Similar)
Both grades are 2.25Cr-1Mo alloy steel.
| Element | T22 | P22 |
| Carbon (C) | ≤ 0.15 | 0.05–0.15 |
| Chromium (Cr) | 1.90–2.60 | 1.90–2.60 |
| Molybdenum (Mo) | 0.87–1.13 | 0.87–1.13 |
| Manganese (Mn) | ≤ 0.60 | 0.30–0.60 |
| Silicon (Si) | ≤ 0.50 | ≤ 0.50 |
Chemistry is essentially the same, but governed by different ASTM standards.
Mechanical Properties (Comparable)
| Property | ASTM A213 T22 | ASTM A335 P22 |
| Tensile Strength | ≥ 415 MPa | ≥ 415 MPa |
| Yield Strength | ≥ 205 MPa | ≥ 205 MPa |
| Elongation | ≥ 20% | ≥ 20% |
Mechanical performance is similar, but acceptance criteria follow different standards.
Heat Treatment Requirements
| Grade | Heat Treatment |
| T22 | Normalized & Tempered |
| P22 | Normalized & Tempered / Q&T |
Both require proper heat treatment to ensure creep resistance and high-temperature stability.
Code & Design Usage
| Aspect | T22 | P22 |
| ASME Boiler Code | ✔✔✔ | ✔ |
| ASME B31.1 / B31.3 | Limited | ✔✔✔ |
| Pressure piping | ✖ | ✔✔✔ |
| Heat transfer tubing | ✔✔✔ | ✖ |
Interchangeability – Important Note
❌T22 tubes cannot replace P22 pipes
❌P22 pipes cannot replace T22 tubes
Even though chemistry is similar, design codes, dimensions, and inspection rules are different.
Comparison Table
| Feature | ASTM A213 T22 | ASTM A335 P22 |
| Product form | Tube | Pipe |
| Main use | Boilers / superheaters | Steam & pressure piping |
| Size system | OD × WT | NPS × Schedule |
| Heat transfer | ✔ Yes | ❌ No |
| Pressure piping | ❌ No | ✔ Yes |
| Chemistry | 2.25Cr-1Mo | 2.25Cr-1Mo |
| Code compliance | Boiler equipment | Piping systems |
Conclusion
ASTM A213 T22 is designed for heat-transfer tubing in boilers and superheaters
ASTM A335 P22 is designed for high-pressure piping in power plants and refineries
