303 stainless steel has the best cutting performance among austenitic stainless steels. It is mainly used in occasions where the production process involves a large number of automatic screw machine cutting processes. The machinability rating (compared to B1212) is approximately 78%. 303 also has a “Ugima” grade, which has better cutting performance and is better than the standard 303 grade.

The improvement of the cutting performance and wear characteristics of 303 stainless steel is due to the addition of sulfur, which also reduces the corrosion resistance of 303, making it lower than that of 304 stainless steel. Like other austenitic stainless steels, 303 stainless steel has excellent toughness, although sulfur slightly reduces its toughness.

It has good corrosion resistance to mildly corrosive environments, but due to the addition of sulfur, the corrosion resistance, weldability and formability are lower than 304 stainless steel. 303 will have stress corrosion cracking in a chloride environment above 50°C; 303 is not suitable for small radius bending operations; it cannot be hardened by heat treatment.

Chemical composition standard

Grade

CMnSiPCrMoNiSeS
303Min

Max

–

0.15

–

2.00

–

1.00

–

0.20

17.0

19.0

–

–

8.0

10.0

–

0.15

–

Mechanical performance standards

Grade

TS(Mpa)YS 0.2% yield point(Mpa)ElongationHardness
Rockwell Hardness(HRB)

Brinell Hardness(HB)

303650(typical)300(typical)45(typical)–

262(Max)

Note:ASTM A582 only specifies the hardness. The above tensile properties are for reference only. Stretched rods up to 25.4mm in diameter have higher strength values and lower elongation.

Physical properties (annealed state)

Grade

Density(kg/m³)Elastic Modulus(Gpa)Average expansion coefficientThermal conductivitySpecific heat

0-100°C(J/kg.k)

Resistance(nΩ.m)
   0-100°C(um/m/°C)0-315°C(um/m/°C)0-538°C(um/m/°C)100°C(w/m.k)500°C(w/m.k)  
303790019317.317.818.416.321.5f00

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