*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 re-tempering. 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.
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Rounds |
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Hardening Temp.: 2175 through 2250°F |
Quench Medium: Salt Bath, Oil, Gas |
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Tempering Range: 1000 through 1100°F |
Typical Hardness Level: 63 to 66 R/C |
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Preheat Forging Temp.: 1400 through 1500°F |
Forging Temp: 2000 through 2075°F |
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Anneal Temp.: 1550 through 1600°F |
Anneal Cooling Method: Furnace cool at 50°F per hr. max to 1000°F, then air cool |
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Anneal Hardness: 255 BHN |
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CPM-M4 Material In Stock |
Color Code: RED & BLACK |
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Flat Dimensions |
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Round Dimensions |
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CPM-M4 Typical Analysis |
· Slight variations from typical analysis shown may occur in order to maintain the desired graphitizing potential. |