ASTM A387 Grade 11 Cl.2 — Chemical Composition & Mechanical Properties
ASTM A387 Grade 11 Cl.2 is a chrome-moly alloy steel grade for pressure-vessel plate (UNS K11789, EN / W.Nr ≈ 1.7335 (13CrMo4-5)). It is also known as 1¼Cr-½Mo plate. 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.
ASTM A387 Grade 11 Cl.2 at a glance
| Specification | ASTM A387 Grade 11 Cl.2 |
|---|---|
| Material family | Chrome-moly alloy steel |
| Product form | Pressure-vessel plate |
| UNS number | K11789 |
| EN / W.Nr equivalent | ≈ 1.7335 (13CrMo4-5) |
| Also known as | 1¼Cr-½Mo plate |
| Document | TG-MG-153 · Rev. 1 · October 2026 |
Typical service
Cr-Mo plate for pressure vessels and fabricated headers
Heat treatment
Normalised and tempered, or quenched and tempered
Chemical composition of ASTM A387 Grade 11 Cl.2 (weight %)
Single values are maximums unless shown as a range or “min”.
Mechanical properties
| Tensile strength, min | 515 MPa |
|---|---|
| Yield strength (0.2 % offset), min | 310 MPa |
| Elongation, min | 22 % |
| Tensile strength, max | 690 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 A387 Grade 11 Cl.2
All equivalents| Standard system | Nearest equivalent grade |
|---|---|
| USA — ASTM / ASME | ASTM A387 Grade 11 Cl.2 · ASME SA-387 Grade 11 Cl.2 |
| USA — UNS | K11789 |
| Europe — EN designation | 13CrMo4-5 (EN 10028-2) |
| Europe — W.Nr | 1.7335 |
| Japan — JIS | SCMV3 (JIS G4109) |
| China — GB / NB | 14Cr1MoR (GB/T 713.2) |
| China — old GB designation | 15CrMoR |
| UK — BS (withdrawn) | BS 1501-621 |
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 A387 Grade 11 Cl.2
All material standardsFAQ
ASTM A387 Grade 11 Cl.2: common questions
What is the minimum yield strength of ASTM A387 Grade 11 Cl.2?
310 MPa, with a minimum tensile strength of 515 MPa.
What is the carbon content of ASTM A387 Grade 11 Cl.2?
0.05–0.17 %.
What is the UNS number and EN equivalent of ASTM A387 Grade 11 Cl.2?
UNS K11789; the nearest European designation is W.Nr ≈ 1.7335 (13CrMo4-5). Equivalents are close but not identical — check the specification if substituting.
How is ASTM A387 Grade 11 Cl.2 heat treated?
Normalised and tempered, or quenched and tempered.
What is the Chinese (GB) equivalent of ASTM A387 Grade 11 Cl.2?
The nearest Chinese equivalent is 14Cr1MoR (GB/T 713.2), formerly 15CrMoR. Equivalents are close but not identical — compare chemistry and properties before substituting.
What is the JIS equivalent of ASTM A387 Grade 11 Cl.2?
The nearest Japanese (JIS) equivalent is SCMV3 (JIS G4109).
Does Teshi Group supply ASTM A387 Grade 11 Cl.2?
Teshi Group supplies this grade as a stockist and supplier. Send your size, rating and quantity to info@teshigroup.com for a quotation with EN 10204 3.1 certificates.
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