303 Stainless
Grade 1.4305 / 303 offers the best machinability of all the austenitic grades due to an addition of sulphur that acts as a chip breaker, making the 303 suitable for applications requiring extensive machining.
Whilst the sulphur addition increases the machinability, it also decreases the corrosion resistance and lowers the materials toughness. It still offers a reasonable corrosion resistance, but the overall corrosion rating is lower than that of 304 and 316 Stainless Steel.
Chemical Composition
| Iron | Rem | Manganese | 2.00% max |
| Chromium | 17.0-19.0% | Carbon | 0.10 % max |
| Nickel | 8.0-10.0% | Sulphur | 0.15-0.35% |
| Silicon | 1.00% max | Phosphorus | 0.05% max |
| Copper | 1.00% max | Nitrogen | 0.1% max |
Related Specifications
BS 303 S31 UNS S30300 DIN 1.4305
EN58M DIN 1.4307 AISI303
Key Features
Very good machining characteristics
Very low magnetism
Good strength levels
Typical Physical Properties
Melting Point 1455°C
Density 8.03 g/cm³
Thermal conductivity 16.3 W/m°K
Thermal expansion coefficient 17.3 x 10-6
Electrical resistivity 0.072 microhm m
Specific Heat 500 J/Kg.K
Modulus of Elasticity 193 GPa
Fabrication Properties
Hot forming temperature Not recommended
Machinability Excellent
Welding Not recommended
Typical Applications
1.4305 / 303 Stainless was developed primarily for heavily machined products such as Fasteners, gears, aircraft fittings, bushings, decorative metalwork and shafts.