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303 Stainless Steel Bar

What is Stainless Steel 303?

Alloy 303 in a non-magnetic, austenitic steel that is not able to be hardened by heat treatment. The machinable nature of Grade 303 stainless steel is due to the presence of Sulphur in its composition. While the Sulphur does improve machining, it also causes a decrease in its corrosion resistance and a slight lowering of the toughness. 

Chemical Composition

Carbon (C)


Manganese (Mn)


Phosphorus (P)


Sulphur (S)


Silicon (Si)


Chromium (Cr)

17.00 – 19.00

Nickel (Ni)

8.00 – 10.00



Southern Tool is a 303 stainless steel distributor and our inventory is available in the following forms:

  • plate
  • round bar
  • square bar
  • hex bar
  • rolled flat bar

Our stainless steel 303 is in compliance with ASTM/ASME: UNS S30300, SAE 30303, AISI 303, DIN 2.4660

What is Stainless Steel 303 Used For?

Alloy 303 is frequently used in applications that require parts to be heavily machined. Some examples include:

  • Nuts and bolts
  • Aircraft fittings
  • Gears
  • Screws
  • Shafts
  • Electrical switchgear components
  • Bushings


Stainless Steel 303 is not generally recommended for welding due to its high Sulphur content which can cause hot cracking.



Heat Treatment


This process should be completed at 1850/1950° F, followed by water quenching to obtain optimum corrosion resistance.


At Southern Tool Steel, we are committed to providing you best-in-class service. Our broad range of quality materials and services is available for distribution nationwide with no minimum order required. 

Contact our service team today for more information on our 303 SS Hex, Round & Square Baror or to discuss your specific needs.