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.