ASTM A335 P23 — Chemical Composition & Mechanical Properties
ASTM A335 P23 is a chrome-moly alloy steel grade for seamless pipe (UNS UNS K41650, EN / W.Nr 1.8201 (7CrWVMoNb9-6)). It is also known as 2¼Cr-1.6W. 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 P23 at a glance
| Specification | ASTM A335 P23 |
|---|---|
| Material family | Chrome-moly alloy steel |
| Product form | Seamless pipe |
| UNS number | UNS K41650 |
| EN / W.Nr equivalent | 1.8201 (7CrWVMoNb9-6) |
| Also known as | 2¼Cr-1.6W |
| Document | TG-MG-141 · Rev. 1 · October 2026 |
Typical service
Waterwall and header piping in supercritical boilers
Heat treatment
Normalised 1040–1080 °C and tempered 730–800 °C
Chemical composition of ASTM A335 P23 (weight %)
Other elements and limits: W 1.45–1.75; V 0.20–0.30; Nb 0.02–0.08; B 0.0010–0.006; Al 0.030 max; Ti 0.005–0.060; Ti/N 3.5 min
Single values are maximums unless shown as a range or “min”.
Mechanical properties
| Tensile strength, min | 510 MPa |
|---|---|
| Yield strength (0.2 % offset), min | 400 MPa |
| Elongation, min | 20 % |
| Hardness | 220 HBW max (97 HRB) |
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 P23
All equivalents| Standard system | Nearest equivalent grade |
|---|---|
| USA — ASTM / ASME | ASTM A335 P23 · ASME SA-335 P23 |
| USA — UNS | UNS K41650 |
| Europe — EN designation | 7CrWVMoNb9-6 |
| Europe — W.Nr | 1.8201 |
| Japan — JIS | STBA24J1 |
| China — GB / NB | 07Cr2MoW2VNbB (GB/T 5310) |
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 P23
All material standardsFAQ
ASTM A335 P23: common questions
What is the minimum yield strength of ASTM A335 P23?
400 MPa, with a minimum tensile strength of 510 MPa.
What is the carbon content of ASTM A335 P23?
0.04–0.10 %.
What is the UNS number and EN equivalent of ASTM A335 P23?
UNS UNS K41650; the nearest European designation is W.Nr 1.8201 (7CrWVMoNb9-6). Equivalents are close but not identical — check the specification if substituting.
How is ASTM A335 P23 heat treated?
Normalised 1040–1080 °C and tempered 730–800 °C.
What is the Chinese (GB) equivalent of ASTM A335 P23?
The nearest Chinese equivalent is 07Cr2MoW2VNbB (GB/T 5310). Equivalents are close but not identical — compare chemistry and properties before substituting.
What is the JIS equivalent of ASTM A335 P23?
The nearest Japanese (JIS) equivalent is STBA24J1.
Does Teshi Group supply ASTM A335 P23?
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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