Stainless Steel Technical Data
Austenitic stainless steels are iron-chromium-nickel alloys which are hardenable only by cold working. Nickel is the main element varied within the alloys of this class while carbon is kept to low levels. The nickel content may be varied from about 4% to 22% - higher values of nickel are added to increase to ductility of the metal. When chromium is increased to raise the corrosion resistance of the metal, nickel must also be increased to maintain the austenitic structure.
These alloys are slightly magnetic in the cold-worked condition, but are essentially non-magnetic in the annealed condition in which they are most often used. The austenitic types feature adaptability to cold forming, ease of welding, high-temperature service, and, in general, the highest corrosion resistance. Following are brief descriptions of some of our most commonly ordered stainless steels:
Type 302 stainless steel is a general purpose material with greater corrosion resistance but less work hardening than Type 301. This is the basic alloy of the austenitic group often referred to as 18:8. Machinability - 40%. Drawing or stamping - good. Welding - very good, tough welds.
Type 304 stainless steel has lower carbon to minimize carbide precipitation. It is less heat sensitive than other 18:8 steels. Used in high-temperature applications. Machinability - 45%. Drawing or stamping – very good. Welding - very good, tough welds.
Type 304L stainless steel has an extra low carbon content to avoid harmful carbide precipitation in welding applications. Its corrosion resistance is comparable to type 304. Machinability - 44%. Drawing or stamping - very good. Welding - very good, recommended for welding.
Type 316 stainless steel contains molybdenum for better corrosion resistance - particularly to pitting. Machinability - 45%. Drawing or stamping - good. Welding - very good, tough welds.
Type 316L stainless steel has a carbon content lower than 316 to avoid carbide precipitation in welding applications. Machinability - 45%. Drawing or stamping - good. Welding - very good, recommended for welding.
Typical Analysis in Percentage:
Type # UNS # C Cr Ni Mn Si S P Mo Cb+Ta
301 S30100 .15 17 7 2.0 1.0 .03 .045
302 S30200 .15 17-19 8-10 2.0 1.0 .03 .04
303 S30300 .12 18 9 2.0 1.0 .03 .04
304 S30400 .08 18-20 8-12 2.0 1.0 .03 .04
304L S30403 .03 18-20 8-12 2.0 1.0 .03 .04
316 S31600 .08 16-18 10-14 2.0 1.0 .03 .04 2.5
316L S31603 .03 16-18 10-14 2.0 1.0 .03 .04 2.5
347 S34700 .08 18 11 2.0 1.0 .03 .045 10 x C
(Percent maximum unless stated as a range or minimum.)
Typical Physical Properties:
Thermal Coefficient of Electrical Magnetic
Specific Heat Conductivity Thermal Expansion Resistivity Permeability
Density BTU/oF/lb BTU/Ft2/Ft/Hr/oF Per oF x 10-6 Microhm-cm (Annealed)
Type # lb/in3 0-100 oC 100 oC 0-100 oC 21 oC μ
301 .29 .12 9.4 9.4 72.0 1.020
302 .29 .12 9.4 9.6 72.0 1.008
303 .29 .12 9.4 9.6 72.0 <1.020
304 .29 .12 9.4 9.6 70.0 1.008
304L .29 .12 9.4 9.6 70.0 1.008
316 .29 .12 9.4 8.9 74.0 1.008
316L .29 .12 9.4 8.9 74.0 1.008
347 .29 .12 9.4 9.6 72.0 1.020
Typical Mechanical Properties:
(Annealed Cond.) Tensile Strength Yield Strength Elongation in Reduction of Brinell
Type # 1000 Psi 1000 Psi 2 inches, % Area, % Hardness
301 105 40 55 70 165
302 90 40 55 70 150
303 90 35 50 55 160
304 85 35 55 70 150
304L 80 30 55 70 140
316 85 35 60 70 150
316L 78 30 55 65 145
347 90 37 50 65 150