Stainless steel properties
Strength, family, and typical uses of common stainless steel grades. The family (austenitic, ferritic, martensitic, or precipitation-hardening) sets corrosion resistance, magnetism, and whether the grade can be hardened by heat treatment.
Common stainless grades
| Grade | Type | Yield (ksi) | Tensile (ksi) | Notes |
|---|---|---|---|---|
| 304 | Austenitic | 31 | 75 | The most common stainless, non-magnetic, good all-round |
| 316 | Austenitic | 31 | 75 | Adds molybdenum for marine and chemical corrosion |
| 303 | Austenitic | 35 | 90 | Free-machining version of 304 |
| 301 | Austenitic | 40 | 110 | Work-hardens strongly, used for springs |
| 321 | Austenitic | 30 | 75 | Titanium-stabilized for high-temperature service |
| 410 | Martensitic | 40 | 75 | Hardenable and magnetic, for valves and shafts |
| 430 | Ferritic | 50 | 75 | Magnetic and low cost, trim and appliances |
| 17-4 PH (H900) | Precipitation | 170 | 190 | Very high strength, shafts and aerospace |
Yield and tensile are typical annealed values for austenitic and ferritic grades; martensitic and precipitation-hardening grades are shown in a hardened condition and are much stronger. Austenitic grades (200 and 300 series) resist corrosion best and are non-magnetic; martensitic and ferritic grades are magnetic.
Comparing stainless against other materials?
See the Material Properties Comparison, or the Yield Strength Chart.
The stainless steel families
Austenitic grades like 304 and 316 contain high chromium and nickel, resist corrosion well, and stay non-magnetic and tough. Ferritic grades like 430 are cheaper, magnetic, and moderately corrosion resistant. Martensitic grades like 410 can be heat treated hard for blades and shafts. Precipitation-hardening grades like 17-4 PH combine high strength with good corrosion resistance.
304 vs 316
304 is the default stainless for most uses. 316 adds two to three percent molybdenum, which sharply improves resistance to chlorides and salt water, making it the choice for marine hardware, chemical equipment, and coastal structures, at a higher cost.
FAQ
What is the most common stainless steel?
Grade 304, an austenitic stainless with good corrosion resistance, formability, and weldability. It suits kitchen equipment, tanks, and general fabrication.
What is the difference between 304 and 316 stainless?
316 adds molybdenum, giving much better resistance to salt and chlorides. Use 316 for marine and chemical environments and 304 for general use.
Is stainless steel magnetic?
It depends on the family. Austenitic grades like 304 and 316 are essentially non-magnetic; ferritic and martensitic grades like 430 and 410 are magnetic.