17-4 stainless steel
SAE type 630 stainless steel (more commonly known as 17-4; also known as UNS 17400) is a grade of martensitic precipitation hardened stainless steel. It contains approximately 15-17.5% (17) chromium and 3-5% (4) nickel, as well as 3-5% copper.[1]
Properties
17-4 can be heat treated to high levels of strength and hardness, and features corrosion resistance[1] and machinability[2] 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.[3]
Applications
Uses for 17-4 include components which require high hardness and/or corrosion resistance at temperatures of up to 600 °F (316 °C).[2] Specific applications for 17-4 include the petroleum and chemical industries, as well as use in aircraft parts.[1]
Composition
| SAE | C | Mn | P | S | Si | Cr | Ni | Cu | Nb+Ta |
|---|---|---|---|---|---|---|---|---|---|
| 630 | 0.07 max | 1.0 max | 0.040max | 0.030 max | 1.0max | 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. Retrieved June 5, 2016.
- 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). Retrieved September 6, 2016.