ASTM A217 C12A — Chemical Composition & Mechanical Properties
ASTM A217 C12A is a chrome-moly alloy steel grade for alloy steel castings (UNS J84090, EN / W.Nr 1.4955 (GX12CrMoVNbN9-1)). It is also known as Cast F91. This sheet summarises its chemical composition limits, minimum mechanical properties, heat treatment and typical service. Teshi Group manufactures valves with bodies in this grade.
ASTM A217 C12A at a glance
| Specification | ASTM A217 C12A |
|---|---|
| Material family | Chrome-moly alloy steel |
| Product form | Alloy steel castings |
| UNS number | J84090 |
| EN / W.Nr equivalent | 1.4955 (GX12CrMoVNbN9-1) |
| Also known as | Cast F91 |
| Document | TG-MG-152 · Rev. 1 · October 2026 |
Typical service
Valve bodies for P91 main steam lines
Heat treatment
Normalised 1040–1080 °C and tempered 730–800 °C
Chemical composition of ASTM A217 C12A (weight %)
Other elements and limits: Nb 0.06–0.10; V 0.18–0.25; Al 0.02 max; Ti 0.01 max; Zr 0.01 max
Single values are maximums unless shown as a range or “min”.
Mechanical properties
| Tensile strength, min | 585 MPa |
|---|---|
| Yield strength (0.2 % offset), min | 415 MPa |
| Elongation, min | 18 % |
| Tensile strength, max | 760 MPa |
| 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 A217 C12A
All equivalents| Standard system | Nearest equivalent grade |
|---|---|
| USA — ASTM / ASME | ASTM A217 C12A · ASME SA-217 C12A |
| USA — UNS | J84090 |
| Europe — EN designation | GX12CrMoVNbN9-1 (EN 10213) |
| Europe — W.Nr | 1.4955 |
| China — GB / NB | C12A / ZG10Cr9Mo1VNbN |
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 A217 C12A
All material standardsFAQ
ASTM A217 C12A: common questions
What is the minimum yield strength of ASTM A217 C12A?
415 MPa, with a minimum tensile strength of 585 MPa.
What is the carbon content of ASTM A217 C12A?
0.08–0.12 %.
What is the UNS number and EN equivalent of ASTM A217 C12A?
UNS J84090; the nearest European designation is W.Nr 1.4955 (GX12CrMoVNbN9-1). Equivalents are close but not identical — check the specification if substituting.
How is ASTM A217 C12A heat treated?
Normalised 1040–1080 °C and tempered 730–800 °C.
What is the Chinese (GB) equivalent of ASTM A217 C12A?
The nearest Chinese equivalent is C12A / ZG10Cr9Mo1VNbN. Equivalents are close but not identical — compare chemistry and properties before substituting.
Does Teshi Group supply ASTM A217 C12A?
Teshi Group manufactures valves with bodies in this grade. Send your size, rating and quantity to info@teshigroup.com for a quotation with EN 10204 3.1 certificates.
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