ASTM A335 P2 — Chemical Composition & Mechanical Properties
ASTM A335 P2 is a chrome-moly alloy steel grade for seamless pipe (UNS K11547). It is also known as ½Cr-½Mo. This sheet summarises its chemical composition limits, minimum mechanical properties, heat treatment and typical service. Teshi Group supplies this grade as a stockist and supplier, and manufactures matching flanges and fittings.
ASTM A335 P2 at a glance
| Specification | ASTM A335 P2 |
|---|---|
| Material family | Chrome-moly alloy steel |
| Product form | Seamless pipe |
| UNS number | K11547 |
| Also known as | ½Cr-½Mo |
| Document | TG-MG-138 · Rev. 1 · October 2026 |
Typical service
½Cr-½Mo high-temperature piping
Heat treatment
Full or isothermal annealed, normalised and tempered 675 °C min, or subcritically annealed 650–705 °C
Chemical composition of ASTM A335 P2 (weight %)
Single values are maximums unless shown as a range or “min”.
Mechanical properties
| Tensile strength, min | 380 MPa |
|---|---|
| Yield strength (0.2 % offset), min | 205 MPa |
| Elongation, min | 30 % |
| Hardness | Not specified |
About chrome-moly alloy steel
Chrome-moly steels are low-alloy steels with 1–9 % chromium and 0.5–1 % molybdenum. Chromium gives oxidation and sulphidation resistance; molybdenum gives creep strength at high temperature. They are the standard choice for steam and hot hydrocarbon service above the carbon-steel range.
Reference information compiled from the published standard for convenience. It does not replace the current edition of the governing standard, which takes precedence. Verify critical dimensions and properties before design, purchase or fabrication. Teshi Engineers & Sales Promoters (P) Ltd accepts no liability for errors or omissions.
International equivalents of ASTM A335 P2
All equivalents| Standard system | Nearest equivalent grade |
|---|---|
| USA — ASTM / ASME | ASTM A335 P2 · ASME SA-335 P2 |
| USA — UNS | K11547 |
| Japan — JIS | STPA20 / SFVAF2 |
| China — GB / NB | 12CrMo (GB/T 5310 12CrMoG) |
| China — old GB designation | 12CrMo |
Equivalents are the nearest commonly cited grades. Chemistry, mechanical properties and testing differ between standards — compare them before substituting one for another.
Standards for ASTM A335 P2
All material standardsFAQ
ASTM A335 P2: common questions
What is the minimum yield strength of ASTM A335 P2?
205 MPa, with a minimum tensile strength of 380 MPa.
What is the carbon content of ASTM A335 P2?
0.10–0.20 %.
How is ASTM A335 P2 heat treated?
Full or isothermal annealed, normalised and tempered 675 °C min, or subcritically annealed 650–705 °C.
What is the Chinese (GB) equivalent of ASTM A335 P2?
The nearest Chinese equivalent is 12CrMo (GB/T 5310 12CrMoG), formerly 12CrMo. Equivalents are close but not identical — compare chemistry and properties before substituting.
What is the JIS equivalent of ASTM A335 P2?
The nearest Japanese (JIS) equivalent is STPA20 / SFVAF2.
Does Teshi Group supply ASTM A335 P2?
Teshi Group supplies this grade as a stockist and supplier, and manufactures matching flanges and fittings. Send your size, rating and quantity to info@teshigroup.com for a quotation with EN 10204 3.1 certificates.
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