Martensitic stainless steels combine moderate corrosion resistance with high strength and hardness; the low-carbon nickel-martensitic grade CA6NM adds toughness and weldability. Precipitation-hardening grades such as CB7Cu-1 (the cast 17-4 PH type) reach high strength through a simple ageing treatment with little distortion.
Grades in this family
| Grade | Type | UNS | Standard | Tensile strength Rm, min. (MPa) | Yield strength Rp0.2, min. (MPa) |
|---|---|---|---|---|---|
| CA15 | 12 % Cr martensitic stainless steel, cast 410 type | J91150 | ASTM A743/A743M, A217/A217M | 620 | 450 |
| CA6NM | 13Cr-4Ni low-carbon martensitic stainless steel | J91540 | ASTM A743/A743M, A487/A487M | 755 | 550 |
| CB7Cu-1 | Precipitation-hardening stainless steel, cast 17-4 PH type | J92180 | ASTM A747/A747M | 1170 | 1000 |
Minimum values (or ranges) for separately cast test bars as specified in
Casting and processing considerations
Properties depend entirely on correct heat treatment, so the required condition must be stated on the drawing or order. Martensitic grades are crack-sensitive during cooling and welding; preheating and controlled tempering are standard practice. For precipitation-hardening grades, homogenisation before solution treatment is often specified for heavier sections.
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.