Carbon and low-alloy steels are the workhorse materials of steel investment casting. Their properties are set mainly by carbon content, alloying with chromium, nickel and molybdenum, and above all by heat treatment: the same grade can be supplied normalised, quenched and tempered or case hardened to very different strength levels.
Grades in this family
| Grade | Type | UNS | Standard | Tensile strength Rm, min. (MPa) | Yield strength Rp0.2, min. (MPa) |
|---|---|---|---|---|---|
| WCB | Weldable carbon steel for pressure parts | J03002 | ASTM A216/A216M | 485–655 | 250 |
| LCC | Carbon-manganese steel for low-temperature pressure parts | J02505 | ASTM A352/A352M | 485–655 | 275 |
| WC6 | 1¼Cr-½Mo steel for high-temperature pressure parts | J12072 | ASTM A217/A217M | 485–655 | 275 |
| WC9 | 2¼Cr-1Mo steel for high-temperature pressure parts | J21890 | ASTM A217/A217M | 485–655 | 275 |
| 4140 | Cr-Mo quench-and-temper steel | G41400 | SAE J404 / AISI 4140 (cast: ASTM A732 Gr. 8Q) | — | — |
| 8620 | Ni-Cr-Mo case-hardening steel | G86200 | SAE J404 / AISI 8620 (cast: ASTM A732 Gr. 13Q) | — | — |
Minimum values (or ranges) for separately cast test bars as specified in
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 delivery specification.