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Stainless steel type 1.4305 is popularly known as grade 303 stainless steel. Grade 303 is the most readily machineable of all the austenitic grades of stainless steel. The machineable nature of grade 303 is due to the presence of Sulphur in the steel composition. Whilst the Sulphur improves machining, it also causes a decrease in the corrosion resistance and a slight lowering of the toughness. The corrosion resistance of type 303 is lower than that for 304. The toughness is still excellent as with other austenitic grades.

Related Standards

Equivalent Materials



Electrical resistivity ρel

7.2E-8 Ω·m at 20 °C


Density ρ

8.03 g/cm³ at 20 °C


Elastic modulus E

193 GPa at 20 °C

Hardness, Brinell HB

230 [-] at 20 °C

Tensile strength Rm

500 - 750 MPa at 20 °C

Yield strength YS

190 MPa at 20 °C


Coefficient of thermal expansion α

1.73E-5 1/K at 20 °C

Melting point Tm

1455 °C

Thermal conductivity λ

16.3 W/(m·K) at 20 °C

Chemical properties


Weight %






17 - 19 %


8 - 10 %


2 %


1 %


Technological properties

Corrosion properties

For 1.4305 sulphur additions to the composition act as initiation sites for pitting corrosion. This decreases the corrosion resistance of 303 (1.4305) stainless steel to less than that for 304. However, corrosion resistance remains good in mild environments. In chloride containing environments over 60°C, 303 stainless steel is subject to pitting and crevice corrosion. Grade 303 stainless is not suitable for use in marine environments.

General machinability

Grade 1.4305 stainless steel has excellent machinability. Machining can be enhanced by adhering to the following rules: Cutting edges must be kept sharp. Dull edges cause excess work hardening. Cuts should be light but deep enough to prevent work hardening by riding on the surface of the material. Chip breakers should be employed to assist in ensuring swarf remains clear of the work. Low thermal conductivity of austenitic alloys results in heat concentrating at the cutting edges. This means coolants and lubricants are necessary and must be used in large quantities.


The sulphur addition present in 1.4305 stainless steel results in poor weldability. If 1.4305 must be welded the recommended filler rods or electrodes are grades 308L and 309 stainless steels. For maximum corrosion resistance, the welds must be annealed.


Type 1.4305 is not readily cold workable. Some cold working is possible but sharp bending should not be attempted. Fabrication methods, like forging, that involve hot working like should occur after uniform heating to 1149-1260°C. The fabricated components should then be rapidly cooled to ensure maximum corrosion resistance.

This material data has been provided by Righton Blackburns.

All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.