Official Answer
Answer
17-7PH (Type 631) stainless steel is a precipitation-hardening alloy that offers an excellent combination of high strength, fatigue resistance, and corrosion resistance. In the CH900 condition, the material is cold-reduced to Condition C and then age-hardened at $900^{\circ}F$ ($482^{\circ}C$) for one hour. This process transforms the martensitic structure and precipitates aluminum-rich intermetallic compounds, raising the tensile strength significantly (up to 240-265 ksi). This high elastic modulus and yield strength allow for thinner cross-sections in wave springs, facilitating miniaturization in medical devices and aerospace sensors while maintaining stable spring rates.
