GENERAL PROPERTIES
Type 17-7PH Precipitation-Hardening Stainless Steel in sheet and strip forms provides valuable property combinations particularly well suited for aerospace applications. This special alloy also provides benefits for other applications requiring high strength and good corrosion resistance, as well as excellent properties for flat springs at temperatures up to 600°F (316°C).
17-7 PH is a precipitation-hardening stainless steel that provides high strength and hardness, excellent fatigue properties, good corrosion resistance and minimum distortion on heat treatment. In the heat treated conditions, 17-7PH stainless steel possesses excellent mechanical properties at temperatures up to 900°F (482°C). Fabrication practices for 17-7PH stainless steel are similar to those used for other chromium-nickel stainless steels.
RESISTANCE TO CORROSION
Corrosion resistance of Type 17-7PH stainless steel in all heat-treated conditions, like other types of stainless steels - will develop superficial rust in some environments. For example, in a marine atmosphere, stainless steels show evidence of rusting after relatively short exposure periods. However, after exposure of one or two years, the amount of rust present is little more than that present at six months.
As with all martensitic steels, 17-7PH stainless steel may be subject to cracking when exposed under stress in environments containing hydrogen sulfide. Such applications are not recommended.
Chemical Composition
TYPE | Cr | Ni | Al | C | Mn | P | S | Si |
---|---|---|---|---|---|---|---|---|
17-7 | min: 16.0 max: 18.0 |
min: 6.75 max: 7.75 |
min: 0.75 max: 1.50 |
0.09 max |
1.00 max |
0.05 max |
0.03 max |
1.00 max |
Mechanical Properties
Grade | Tensile Strength ksi (MPa) | Yield Strength 0.2% ksi (min) | Elongation % | Hardness (Rockwell) MAX |
---|---|---|---|---|
17-7 | 130 | 40 | 35 | B85 |
Physical Properties
Density lbm/in3 |
Thermal Conductivity (BTU/h ft. °F) |
Electrical Resistivity (in x 10-6) |
Modulus of Elasticity (psi x 106 |
Coefficient of Thermal Expansion (in/in)/ °F x 10-6 |
Specific Heat (BTU/lb/ °F) |
Melting Range (°F) |
---|---|---|---|---|---|---|
at 68°F: 0.2820 | 117 —- | 30.7 at 68°F | 28.5 | 8.5 at 32 – 212°F | 0.1200 at 68°F to 212°F | 2560-2625°F |