Alloy SST-303 is primarily employed in applications which need good machinability. For applications requiring a higher machinability there is a stainless steel alloy 303 called “Ugima” that is often used.

Ugima 303 alloy’s increased machinability is due to the addition of sulphur in the composition of the alloy. Although sulphur increases the machinability, it also results in steel with lowered toughness and corrosion resistance.

Another alternative to alloy SST-303 is the stainless steel alloy 303Se which contains selenium. Although the selenium lowers the metal’s machinability, it does produce a surface finish that is smoother and has an improved cold and hot formability.

Stainless steel alloys SST-304, SST-316 and SST-416 are considered viable substitutes for alloy SST-303. They are often used due to either better formability, better resistance to corrosion, and higher or lower machinability.

Marine applications are not suitable for the stainless steel alloy 303 despite the alloy’s ability to resist corrosion. The corrosive atmosphere of a marine or saltwater environment can result in excessive pitting. Exposure to chloride environments is also likely to produce cracks in the metal.

The alloy 303 does not respond well to welding or forming due to the addition of sulphur. Sharp bends are also not recommended for SST-303, which explains the use of 304 Ugima for such applications. SST-303 is also not the best choice for heat treatment hardening.

Alloy 303 applications include gears, bushings, nut and bolts, electrical switchgear components and shafts. In fact, any part requiring corrosion resistance, with the ability to withstand heavy machining or fabrication should employ alloy SST-303.


To learn more about the stainless steel alloy SST-303.