302 Stainless Steel
Type 302 Stainless Steel is an austenitic chromium-nickel stainless steel, non-hardenable by thermal treatments. It may be cold worked to high tensile strengths with slightly lower ductility than Type 301. Its corrosion resistance is superior to that of Type 301. Type 302 is essentially nonmagnetic in the annealed condition and becomes slightly magnetic when cold worked.
ASTM A240, A666
Automotive and architectural trim, springs, kitchen and restaurant equipment and utensils, dairy and food processing equipment
Chemical Composition: (ASTM A240, A666)
|Nickel8.00 – 10.00|
Mechanical Properties: (ASTM A240, A666)
|Type||Yield Strength 0.2% offset (KSI)||Tensile Strength (KSI)||% Elongation (2" Gauge length)||Hardness Rockwell|
|302 Ann||30 min.||75 min.||40 min.||HRB 92|
|302 ¼ Hard||75 min.||125 min.||12 min.||HRC 25 - 32(typical)|
|302 ½ Hard||110 min.||150 min.||10 min.||HRC 32 - 37(typical)|
|302 ¾ Hard||135 min.||175 min.||6 min.||HRC 37 – 41(typical)|
|302 Full Hard||145 min.||185 min.||4 min.||HRC 41 – 47 (typical)|
Physical Properties: (annealed)
|Density (lb./ in^2) @ RT||0.29|
|Modulus of Elasticity in Tension (psi x 10^6)||28.0|
|Specific Heat (BTU/o F/lb.)||32 to 212 oF||0.12|
|Thermal Conductivity (BTU/hr/ft^2/ft)||212oF||9.4|
|Mean Coefficient of Thermal Expansion (in. x 10^-6 per o F)||32 to 212oF||9.6|
|32 to 600oF||9.9|
|32 to 1,000oF||10.2|
|32 to 1,200oF||10.4|
|Electrical Resistivity (micro ohms - cm)||at 70oF||72.0|
|Melting Point Range (oF)||2550/2590|
|Oxidation Resistance - Continuous Service(oF)||1650|
|Oxidation Resistance - Intermittent Service(oF)||1500|
Hardening Type 302 can be hardened only by cold working. Annealing Heat in the range of 1850-2050°F and cool rapidly. Light gauges (under 16 gauge) may be air cooled. Heavier sections require water quenching from annealing temperature. Stress Relieving The recommended temperature range for stress relieving is 400-750°F.
Type 302 can be formed into most shapes. It work hardens rapidly, so it may be necessary to anneal between forming steps.
Type 302 is weldable by electric arc, gas fusion or electrical resistance processes. In heavy sections, the material may develop poor resistance to chemical attack due to to carbide precipitation in the heat affected region of the weld. Restoration of normal corrosion resistance can be obtained by heating to 1750-2000°F and cooling rapidly. If subsequent annealing is impractical, then Type 304L or one of the stabilized grades should be used. Type 308 filler metal is used for welding Type 302.
Type 302 stainless steel in the annealed condition is highly resistant to corrosive conditions in urban and rural environments. It is resistant to most organic acids.