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AISI 303/ALLOY 303/SS 303

Alloy 303 is a non-magnetic, austenitic stainless steel which is not hardenable by heat treatment. It is the free-machining modification of the basic 18% chromium - 8% nickel stainless steel.

Resistance to Oxidation Alloy 303 has good resistance to oxidation at temperatures up to 1700° F (927° C). In extreme oxidizing atmospheres, irregular scaling may be encountered, particularly above 1400° F (760° C). The rate of oxidation of all stainless steels is greatly affected by the service atmosphere, by heating and cooling cycles, and by design considerations

Machining The same machining methods commonly used for mild steel are applicable to Alloy 303. High machining rates can be obtained for these materials in the annealed condition with hardnesses in the range of 200 to 240 Brinell. However, modifications in machining techniques are necessary to adjust to the special characteristics of each type of stainless steel.?Since Alloy 303 will work harden, it should be machined at reduced surface feet per minute and heavier feeds to prevent glazing at the tool interface.

Annealing Temperatures For maximum ductility, Alloy 303 should be annealed near the upper limit of the 1800 - 2000°F (982 - 1043°C) range. The material should be water quenched from the annealing temperature to prevent harmful carbide precipitation. For the same reason, heating within the 800 - 1500°F (427 - 816°C) temperature range should be avoided unless the material can be subsequently annealed.

Hardening Temperature Alloy 303 is austenitic and cannot be hardened by heat treatment.

Structure Alloy 303 is austenitic at all temperatures. When heated within the range 800 - 1500°F (427 - 816°C), carbides will precipitate at the grain boundaries. Upon reannealing, the carbides will be re


Standard AISI 303
UNS S 30300
Werkstoff Nr. 1.4305

Mechanical & Physical Properties

Density 8.03 g/cm3
Melting Point 1440 °C (2552 °F)
Tensile Strength Psi - 75000-90000
MPa - 517-621
Yield Strength (0.2%Offset) Psi - 30000-40000 MPa - 207-276
Elongation 35-50%

Chemical Composition

AISI 303
Ni 8.0 - 10.0
C 0.15 Max
Mn 2.00 Max
Si 0.1 Max
Cr 17-19
Mo 0.60 Max
Ti --
S 0.15 Min


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