Chromium-nickel grade of stainless steel. May be hardened by single low-temperature heat treatment, yielding excellent mechanical properties at a high-strength level, and minimizing scaling and distortion. This grade should not be used in the solution-treated condition.
ASTM A564 Type 630, AMS 5643
The corrosion resistance of 17-4 is superior to straight chromium grades like Type 410, and approaches that of the chromium-nickel grades. It is equal to 304 in many corrosive media. The corrosion-resistant properties hold up in service and temperatures up to 800° F