S7 is a shock resisting tool steel with excellent toughness and high strength, along with medium wear resistance. It has maximum shock resistance and high compression strength, which gives it good deformation resistance in use, while retaining good toughness. S7 is easy to machine in the annealed condition and can be readily heat treated. It can be quenched in air, exhibiting minimal distortion on hardening. S7 also has medium hot work characteristics, making it a versatile tool steel for both cold and warm shock applications, as well as plastic molds that require high hardness.
Typical applications for S7 tool steel are punches, chisels, blanking dies, forming dies, cold and warm header dies, shears, compression dies, hobbed dies, high hardness plastic molds, zinc die casting dies, gripper dies, etc.
Preheat 1200°-1300°F. Forge at 2000°-2050°F. Stop at 1700°F and cool slowly.
1500°-1550°F, cool slowly to 1000°F, air cool. Brinell 197 max.
1200°-1300°F, prior to hardening.
1750°F. Quench in air if cross section is 2-1/2" or smaller; sections 2-1/2" to 6" should be oil quenched to black (1000°F) followed by air cooling to 150°F. Larger cross sections should be oil quenched to 150°F.
Double temper one hour per inch of section thickness to desired heating rate of 2 hours per inch. Cool in air to room temperature between the two tempers. Suggested: Cold working applications 400°-500°F. Hot working applications 900°-1000°F.
Air Cool Oil Quench Tempering Hardness Hardness Temperature F Rockwell C Rockwell C As Quenched 60 61 200 59.5 60.5 300 58.5 60 400 57 58.5 500 55.5 55.5 600 54 54 700 53.5 53.5 800 52.5 52.5 900 51.5 52 1000 50.5 51.5 1100 48 48.5 1200 37.5 37.5 1300 25.5 26.5