Stainless Steel 303
Stainless Steel 303 – Free-Machining Austenitic Stainless for Precision Turned Parts
Stainless Steel 303 is the most machinable grade in the stainless steel family, achieved through a deliberate sulfur addition that promotes chip breaking and reduces tool wear. While it sacrifices some corrosion resistance compared to 304, it excels in high-volume screw machine production of fasteners, fittings, and precision turned components where surface finish and throughput are priorities.
Key Properties
- Tensile Strength: 620 MPa
- Hardness: 228 HB
- Machinability: Best in the stainless family
- Weldability: Not recommended
- Sulfur Addition: Promotes short chip breaking
- Standard: ASTM A582
Common Applications
Precision screw machine parts, nuts, bolts, shafts, bushings, fittings, gears, and high-volume CNC-turned components where tight tolerances and excellent surface finish are required without welding demands.
Material properties
| Material name | Stainless Steel 303 |
|---|---|
| Type | Stainless Steel |
| Standard code | ASTM A582 |
| Tensile strength (MPa) | 620 |
| Yield strength (MPa) | 240 |
| Fatigue strength (MPa) | 241 |
| Elongation (%) | 35 |
| Hardness (Brinell) | 228 |
| Density (g/cm³) | 8 |
| Electrical resistivity (µΩ·in) | 72 |
| Thermal conductivity (W/m·K) | 16.2 |
| Melting range (°C) | 1400–1420 |
| Weldability | Poor |
| Formability | Fair |
| Shear modulus | 74 |
| Industry code | ss_303 |