Stainless Steel Technical Data

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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