G17CrMo9-10 (1.7379) — 2¼Cr-1Mo steel for high-temperature pressure parts

Designation

Grade: G17CrMo9-10 (1.7379)
UNS: —
EN designation: 1.7379 (G17CrMo9-10)
Standard: EN 10213
Family: Carbon and low-alloy steels
Density: ≈ 7.85 g/cm³
Usual delivery condition: Quenched (or normalised) and tempered

Chemical composition

Element	Mass fraction, %
C	0.13–0.20
Mn	0.50–0.90
Si	≤ 0.60
Cr	2.00–2.50
Mo	0.90–1.20
Fe	bal.

Main elements only. Phosphorus, sulphur and residual-element limits are specified in the standard and are not reproduced here.

Mechanical properties

Condition	Tensile strength Rm, min. (MPa)	Yield strength Rp0.2, min. (MPa)	Elongation, min. (%)
Quenched (or normalised) and tempered	590–740	400	18

Minimum values (or ranges) for separately cast test bars as specified in EN 10213.

Characteristics

Corrosion and oxidation behaviour: Not corrosion resistant; coating or other protection required in corrosive environments
Weldability: Possible with qualified procedure; preheat and/or post-weld heat treatment as specified
Machinability: Good in the appropriate heat-treatment condition
Typical applications: Valves Energy High-temperature service Pressure parts

International cross-reference

System	Designation	Relationship
ASTM	WC9 (ASTM A217/A217M)	Comparable properties

Casting and processing considerations

Good castability and moderate pouring temperatures. Surface decarburisation from the reaction between metal, shell and atmosphere has to be considered on heat-treated and wear surfaces; machining allowance or a controlled furnace atmosphere are common countermeasures. Section-size sensitivity of quenched and tempered grades should be reflected in the drawing requirements.

Reference data compiled from the cited standards for orientation. Always work from the current edition of the governing specification; values are not a guaranteed LOSTWAX TR delivery specification.

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