SAE Type 630 stainless steel (more commonly known as 17-4 PH, or simply 17-4; also known as UNS S17400) is a grade of martensitic precipitation hardened stainless steel. It contains approximately 15–17.5% chromium and 3–5% nickel, as well as 3–5% copper.[1] The name comes from the chemical makeup which is approximately 17% chromium and 4% nickel. SUS630 is the same as 17-4PH, and they both refer to the same grade. [2]
Properties
17-4 can be heat treated to high levels of strength and hardness, and features corrosion resistance[1] and machinability[3] comparable to austenitic 304 stainless. Being martensitic, 17-4 is magnetic.
17-4 is capable of being hardened up to approximately 44 Rc when heat treated to condition H900.[1]
Overaging (aging beyond the peak strength condition) improves resistance to stress corrosion cracking.[4]
Applications
Uses for 17-4 stainless steel include components which require high hardness and corrosion resistance at temperatures of up to 600 °F (300 °C).[3] Specific applications for 17-4 include parts for aerospace, petroleum, chemical, and firearm industries.[1]
Composition
| C | Mn | P | S | Si | Cr | Ni | Cu | Nb, Ta |
|---|---|---|---|---|---|---|---|---|
| 0.07 max. | 1.0 max. | 0.04 max. | 0.03 max. | 1.0 max. | 15.0–17.5 | 3.0–5.0 | 3.0–5.0 | 0.15–0.45 |
References
- 1 2 3 4 5 "Type 630; 17 Cr-4 Ni; UNS 17400" (PDF). Outokumpu.com. Archived from the original (PDF) on December 23, 2015. Retrieved June 5, 2016.
- ↑ "SUS 630(17-4PH)" (PDF). Atlas Steels. Retrieved April 23, 2021.
- 1 2 3 "North American Stainless – Long Products Stainless Steel Grade Sheet" (PDF). North American Stainless. Retrieved June 5, 2016.
- ↑ "Stress Corrosion Properties of High-Strength Precipitation Hardening Stainless Steels in 3.5% Aqueous Sodium Chloride Solution" (PDF). Archived from the original (PDF) on September 6, 2015. Retrieved September 6, 2016.