Designation Cross-Reference

1.4903 — ASTM Equivalent

Holding a datasheet that specifies 1.4903 (EN wrought)? The valve-grade equivalent, its properties, and certified supply of the matching ASTM grade.

What is the ASTM equivalent of 1.4903?

1.4903 is a EN wrought designation corresponding to ASTM A182 F91 (P91 Chrome-Moly (9Cr-1Mo-V)) for industrial valve service. The full grade data is below - equivalence is by nominal chemistry and mechanical class, so confirm composition and heat-treat condition against the governing standard before substituting in critical service.

A182 F91

Chrome-Moly / Alloy Steel

P91 Chrome-Moly (9Cr-1Mo-V) - forged form.

Service temperature-18°C to +650°C

Nominal compositionC 0.08–0.12%, Cr 8.0–9.5%, Mo 0.85–1.05%, V 0.18–0.25%, Nb 0.06–0.10%, N 0.03–0.07%. Martensitic.

Typical service: Supercritical power plant steam (>22 MPa, >560°C); Ultra-supercritical (USC) steam (>600°C); Hydrogen service at elevated temperature

Also designated:X10CrMoVNb9-1 [EN wrought]1.4903 [EN wrought]X10CrMoVNb9-1 [DIN]STPA92 [JIS]

Reviewed by Materials Engineering, Vajra Industrial SolutionsDiscipline: Valve Metallurgy & Materials SelectionLast reviewed: 20 June 2026

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Engineering references

A182 F91 full grade pageP91 Chrome-Moly (9Cr-1Mo-V)Equivalence MatrixAll 43 grades across 7 systems Designation lookup directoryEvery foreign designation indexed