Guides/Comparisons
17-4 PH vs 316 stainless steel
17-4-ph-vs-316-stainless-steel17-4 PH stainless steel and Stainless steel 316 at a glance
This page compares 17-4 PH stainless steel and Stainless steel 316 using only values that carry a source, a test condition and an evidence level. Ranges run across temper, heat treatment and product form, measured at room temperature where the source says so.
- Composition: Chromium (17-4 PH 15 to 17.5%; 316 16 to 18%), Nickel (17-4 PH 3 to 5%; 316 10 to 14%), Carbon (17-4 PH up to 0.07%; 316 up to 0.08%), Manganese (17-4 PH up to 1%; 316 up to 2%).
- Yield strength: 17-4 PH is higher (17-4 PH 725 to 1,262 MPa; 316 193 to 213 MPa), about 4.9 times the midpoint of 316.
- Tensile strength: 17-4 PH is higher (17-4 PH 930 to 1,365 MPa; 316 480 to 620 MPa), about 2.1 times the midpoint of 316.
- Density: 316 is higher (17-4 PH 7.75 to 7.86 g/cm³; 316 7.87 to 8.07 g/cm³), a difference of under 10% at the midpoint.
- Young's modulus: the ranges overlap (17-4 PH 196 to 201 GPa; 316 190 to 205 GPa).
- Thermal conductivity: 17-4 PH is higher (17-4 PH 17.9 to 22.6 W/(m·K); 316 13 to 17 W/(m·K)), about 1.4 times the midpoint of 316.
- Melting point: the ranges overlap (17-4 PH 1,404 to 1,440 °C; 316 1,375 to 1,440 °C).
- Service temperature: 316 is higher (17-4 PH 316 °C; 316 750 to 925 °C), about 2.6 times the midpoint of 17-4 PH.
- Thermal expansion: 316 is higher (17-4 PH 11.2 to 13 ppm/K; 316 16.5 to 18.2 ppm/K), about 1.4 times the midpoint of 17-4 PH.
- Yield strength for each unit of density (calculated from each grade's midpoint values): 17-4 PH stainless steel 127 MPa per g/cm³; Stainless steel 316 25.5 MPa per g/cm³.
"Higher" means the whole range is higher, not just one value. Where a value is a specified minimum, the table says "at least".
Side by side
| Property | 17-4 PH stainless steel | Stainless steel 316 |
|---|---|---|
| Yield strength | 725 to 1,262 MPa | 193 to 213 MPa |
| Tensile strength | 930 to 1,365 MPa | 480 to 620 MPa |
| Density | 7.75 to 7.86 g/cm³ | 7.87 to 8.07 g/cm³ |
| Young's modulus | 196 to 201 GPa | 190 to 205 GPa |
| Thermal conductivity | 17.9 to 22.6 W/(m·K) | 13 to 17 W/(m·K) |
| Melting point | 1,404 to 1,440 °C | 1,375 to 1,440 °C |
| Service temperature | 316 °C | 750 to 925 °C |
| Thermal expansion | 11.2 to 13 ppm/K | 16.5 to 18.2 ppm/K |
| Yield strength per densitycalculated | 127 MPa per g/cm³ | 25.5 MPa per g/cm³ |
Composition
| Element | 17-4 PH stainless steel | Stainless steel 316 |
|---|---|---|
| Iron | balance | balance |
| Chromium | 15 to 17.5% | 16 to 18% |
| Nickel | 3 to 5% | 10 to 14% |
| Copper | 3 to 5% | not listed |
| Niobium plus tantalum | 0.15 to 0.45% | not listed |
| Carbon | up to 0.07% | up to 0.08% |
| Manganese | up to 1% | up to 2% |
| Silicon | up to 1% | up to 0.75% |
| Phosphorus | up to 0.04% | up to 0.045% |
| Sulfur | up to 0.03% | up to 0.03% |
| Molybdenum | not listed | 2 to 3% |
| Nitrogen | not listed | up to 0.1% |
Shares are as printed in the sources, by weight.
When to use which
| Material | Best for | Weakest at |
|---|---|---|
| 17-4 PH stainless steel | High-strength fittings, fasteners, shafts and valve parts that need more strength than 304 and moderate corrosion resistance | Stress corrosion cracking and pitting in peak-aged (H900) material, and crevice corrosion in stagnant salt water |
| Stainless steel 316 | Chloride-bearing and marine-grade service where 304 would pit, in annealed sheet, bar and plate | Crevice and pitting attack in seawater condenser tubes, intergranular attack after heating between 500 and 900 C, and modest strength next to precipitation-hardened grades |
Where each is used
| Material | Use |
|---|---|
| 17-4 PH stainless steel | Aircraft and missile fittings |
| 17-4 PH stainless steel | Bolts and fasteners |
| 17-4 PH stainless steel | Jet engine stator vanes |
| 17-4 PH stainless steel | Pump shafts, valve parts and rotors |
| Stainless steel 316 | Aerospace structures |
| Stainless steel 316 | Chemical storage, food processing and oil refining equipment |