17Cr-4Ni is a martensitic stainless steel characterized by moderate chromium content (17%), elevated cobalt (~8.5%), and significant silicon (~3.6%), which together promote high strength and hardness through precipitation hardening and martensitic transformation. This alloy is primarily used in demanding aerospace, defense, and tooling applications where high strength combined with corrosion resistance is required, and its cobalt addition distinguishes it from standard martensitic stainless steels by enhancing strength and thermal stability. The material competes with 17-4 PH and 15-5 PH variants in applications requiring a balance of machinability, strength, and environmental durability without the full cost of superalloys.
Compliance & Regulations
| Property | Value | Unit | Conditions | Source | |
|---|---|---|---|---|---|
Elongation at Break(εf) | 17.00 | - | — | ||
Ultimate Tensile Strength(σUTS) | 195.9 | ksi | — | ||
Yield Strength (0.2% offset)(σy) | 165.9 | ksi | — |