*Always consult your Heat Treater*
      *Information Provided is General*

S-7 is an air or oil hardening die steel with an unique combination of toughness and wear resistance properties making it an ideal choice for many tooling applications. An intermediate carbon level balanced with moderate amounts of chromium and molybdenum provides the outstanding properties of this grade. S-7 die steel is used successfully for both cold and hot tooling applications as the result of its unusual combination of properties. This grade is recommended for cold work tools such as shear blades, swaging dies, gripper dies, chisels and punches which require a high degree of shock resistance. It is also suitable for dies used in plastic molding and other applications where operating temperatures are below 1000°F. Another desirable feature of this grade is its ease of heat treatment and the excellent resistance to distortion during air hardening. Additional economies are realized from the good machinability of this grade, which is comparable to standard grades of oil hardening tool steel.

Heat slowly to 1725°F, hold at this temperature until thoroughly and uniformly heated and then either air or oil quench. For most tools, air-cooling will develop full hardness but sections over 2 ½ inches in thickness or diameter should be quenched in oil. When oil quenching is used it’s suggested that a flash quench to 900°F be employed, followed by air-cooling to 125-150°F before tempering. When furnace hardening use a holding time of 30 minutes for tools up to 1 inch in thickness and 15 additional minutes for each inch of thickness over 1 inch.

After cooling to 125-150°F it should immediately be treated slowly to the tempering temperature and held at heat for 1 hour per inch of thickness followed by air-cooling. Most cold work tools are tempered within the 400-500°F range; for hot work applications a tempering temperature of 900-1000°F is suggested.

Hardening happens around 1725°F.

S-7 is an oversized material.


  •  + .015 up to .040 on thickness

  •  + .080 up to .125 on width


  •  Up to 1″ + .007 up to .0181

  •  1” up to 6″ + .015 up to .0406

  •  6” and up + .0625 up to .250

 Hardening Temp.:    1725°F

 Quench Medium:    Air Salt Bath

 Tempering Range:    300 thru 1000°F

 Typical Hardness Level:   50 58 R/C

 Preheat Forging Temp.:    1450 thru 1500°F

 Forging Temp:    1950 thru 2050°F

 Anneal Temp.:

 Anneal Cooling Method:    Furnace cool at 25°F per hr. max. to 1000°F  or less, then air cool or furnace cool

 Anneal Hardness:    223 BHN

 S-7 Material In Stock

 Color Code:     RED and WHITE 

 Flat Dimensions

  • 1/2″ x 3/4″ up to 6″ x 6″

  • Non-standard sizes, quoted upon request

 Round Dimensions

  • 3/8″ up to 12″

  • Non-standard sizes quoted upon request.

 S-7 Typical Analysis:











 · Slight variations from typical analysis shown may occur in order  to maintain the desired graphitizing potential.