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

M-4 is a super high-speed steel having a very high carbon and vanadium content for exceptional abrasion resistance. It is well suited for premium-cutting tools of all types, and particularly those used for machining abrasive alloys, castings and heat-treated materials. The higher carbon content enables M-4 to be consistently heat treated in excess of Rockwell C 65. However, this feature and the excess of vanadium carbides means that M-4 is more difficult to grind after heat treatment than M-2 or other super high-speed steels as M-42.

Hardening in properly rectified salt baths or controlled atmosphere or vacuum furnaces is recommended. Preheat thoroughly at 1450 – 1550°F, then transfer to the high heat of 2175 – 2225°F in a salt bath or 2200 – 2250°F in an atmosphere or vacuum furnace. A slight soak at the high heat will assist in developing maximum hardness, but avoid over-soaking. Quench into salt maintained at 1000 – 1100°F, or warm oil. After equalizing at the quench bath temperature, complete the quench in still air down to at least 150°F prior to beginning the tempering operation. If oil quenched, remove from the oil at about 900°F and air cool.

Large tools made of high vanadium high speed steel such as M-4 may not attain full hardness with a standard interrupted salt quench and it may be necessary to remove from salt bath quench at about 1500° F, then oil quench down to a temperature of about 900°F, or until the tool loses all color. Then complete quench in air. This technique will assist in promoting maximum hardness.

M-4 should be tempered in the range of 1000 – 1100°F for most applications. Hold at temperature for 2-4 hours. Cooling should be carried out in still air and always allow the tools to reach room temperature before retempering. Double tempering is recommended and a third temper at 800 – 1000°F after finish grinding is often beneficial.

Hardening happens between 2175 – 2250°F.

M-4 is an oversized material.


  •  + .015 up to .040 on thickness

  •  + .080 up to .125 on width


  •  Up to 1″ + .007 up to .018

  •  1” up to 6″ + .015 up to .040

  •  6” and up + .0625 up to .250

 Hardening Temp.:    2175 through 2250°F

 Quench Medium:    Salt Bath, Oil, Gas

 Tempering Range:    1000 through 1100°F

 Typical Hardness Level:    63 to 66 R/C

 Preheat Forging Temp.:    1400 through 1500°F

 Forging Temp:    2000 through 2075°F

 Anneal Temp.:    1550 through 1600°F

 Anneal Cooling Method:    Furnace cool at 50°F per hr. max to 1000°F, then air cool

 Anneal Hardness:    255 BHN

 PM-M4 Material In Stock

 Color Code:   RED & BLACK

 Flat Dimensions

  • 3/8″ x 15 up to 4″ x 4″

  • Non-standard sizes, quoted upon request

 Round Dimensions

  • 1/4″ up to 5″

  • Non-standard sizes quoted upon request.

 PM-M4 Typical Analysis















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