0Cr17Ni4Cu4Nb 17-4PH steel is a martensitic precipitation hardening stainless steel, the steel can easily adjust the strength level, and its strength can be adjusted by changing the heat treatment process. Martensitic phase transformation and aging treatment to form a precipitation-hardening phase are its main means of strengthening. Due to 0Cr17Ni4Cu4Nb low carbon, high chromium, and copper, its corrosion resistance is better than the Cr13 type and 9Cr18, 1Cr17Ni2 martensitic steel.
In addition, the steel attenuation performance is good, corrosion fatigue and droplet erosion resistance are better than 12% Cr martensitic steel, and the welding process is simple and easy to manufacture. Still, it is more difficult to carry out the depth of the cold molding. 0Cr17Ni4Cu4Nb is mainly used in both the requirements of stainless steel and the requirements of weak acid, alkali, salt corrosion-resistant high-strength parts. Such as turbine final blades and in a corrosive environment, the working temperature is less than 300 ℃ structural components.
Chemical Composition of 0Cr17Ni4Cu4Nb
| Element | C | Mn | P | S | Si | Cr | Ni | Cu | Nb + Ta |
|---|---|---|---|---|---|---|---|---|---|
| Content | ≤ 0.07% | ≤ 1.00% | ≤ 0.04% | ≤ 0.03% | ≤ 1.00% | 15.00-17.50% | 3.00-5.00% | 3.00-5.00% | 0.15-0.45% |
This precipitation-hardening stainless steel combines high strength, good corrosion resistance and excellent mechanical properties at temperatures up to 316°C (600°F).
Physical and Chemical Properties of 0Cr17Ni4Cu4Nb
After heat treatment: hardening 480°C (896°F) – 1 hour – air cooling, the following physical properties were obtained:
| Interval temperature | Thermal Expansion ax10-6°C-1 | °C | °F | Thermal Conductivity w.m-1.K-1) | |
| 0-100 | 10.8 | 20 | 68 | 14 | |
| 0-200 | 11 | 100 | 212 | 16 | |
| 0-300 | 11.3 | 200 | 392 | 18.5 | |
| 0-400 | 11.6 | 300 | 572 | 20 | |
| 0-500 | 12 | 400 | 752 | 22 | |
| 500 | 932 | 23 | |||
| Interval temperature | Thermal Expansion ax10-6°C-1 | °C | °F | Young’s Modulus (GPa) | |
| 0-100 | 10.8 | 20 | 68 | 197 | |
| 0-200 | 11 | 100 | 212 | 193 | |
| 0-300 | 11.3 | 200 | 392 | 186 | |
| 0-400 | 11.6 | 300 | 572 | 180 | |
| 0-500 | 12 | 400 | 752 | 175 | |
| 500 | 932 | 170 | |||
Processing Performance and Welding Process
The hot working temperature of 0Cr17Ni4Cu4Nb is 1000～1170℃. For parts with large cross-sectional size (≥75mm) or complex shape, they should be returned to the furnace and heated to the original hot working temperature in time after hot working, and then slowly cooled.
Scope of Use and Application
0Cr17Ni4Cu4Nb steel is the preferred material for low-end blades of steam turbines. It is a structural material under corrosive conditions with an operating temperature below 300°C. In addition, it is the main structural material for parts that require not only stainless steel, but also weak acid, alkali, and salt corrosion resistance, and high strength. It is mainly used for wear-resistant and corrosion-resistant high-strength parts of control rod drive mechanisms in fan reactor environments.
