17-4PH Stainless Steel
17-4 Precipitation Hardening also known as Type 630 is a chromium-copper precipitation hardening stainless steel used for applications requiring high strength and a moderate level of corrosion resistance. High strength is maintained to approximately 600 degrees Fahrenheit (316 degrees Celsius).
General Properties
Alloy 17-4 PH is a precipitation hardening martensitic stainless steel with Cu and Nb/Cb additions. The grade combines high strength, hardness (up to 572°F / 300°C), and corrosion resistance.
Mechanical properties can be optimized with heat treatment. Very high yield strength up to 1100-1300 MPa (160-190 ksi) can be achieved.
The grade should not be used at temperatures above 572°F (300°C) or at very low temperatures. It has adequate resistance to atmospheric corrosion or in diluted acids or salts where its corrosion resistance is equivalent to Alloy 304 or 430.
| Applications | Standards |
- Offshore (foils, helicopter deck platforms, etc.)
- Food industry
- Pulp and paper industry
- Aerospace (turbine blades, etc.)
- Mechanical components
- Nuclear waste casks
| - ASTM A693 grade 630 (AMS 5604B) UNS S17400
- EURONORM 1.4542 X5CrNiCuNb 16-4
- AFNOR Z5 CNU 17-4PH
- DIN 1.4542
|
Corrosion Resistance
Alloy 17-4 PH withstands corrosive attacks better than any of the standard hardenable stainless steels and is comparable to Alloy 304 in most media.
If there are potential risks of stress corrosion cracking, the higher aging temperatures then must be selected over 1022°F (550°C), preferably 1094°F (590°C). 1022°F (550°C) is the optimum tempering temperature in chloride media.
1094°F (590°C) is the optimum tempering temperature in H2S media.
The alloy is subject to crevice or pitting attack if exposed to stagnant seawater for any length of time.
It is corrosion resistant in some chemical, petroleum, paper, dairy and food processing industries (equivalent to 304L grade).
If you would like to know more about 17-4PH stainless steel then click 17-4PH Technical Data.
The properties mentioned below pertain to commonly available grade 630 bar products in ASTM A564. The specifications may not be similar to other forms such as forgings and plates.
Composition Composition of 17-4PH stainless Steel
The compositional ranges of grade 630 stainless steels are displayed below:
| Grade | C | Mn | Si | P | S | Cr | Ni | Cu | Nb+Ta |
| 630 | min. max | - 0.07 | - 1 | - 1 | - 0.04 | - 0.030 | 15 17.5 | 3 5 | 3 5 | 0.15 0.45 |
