4142 H.T. Tool Steel
|Tempering Temp. º(F):||Hardness Rc|
Brake die, support tooling, die holders, short run stamping and bending dies.
Heat slowly and uniformly to a temperature of from 1750° F to 1850° F. Cool slowly from the forging or rolling temperature.
Heat slowly to 1500° F, and hold for 1/2 hour per inch of thickness. Furnace cool at 20° F per hour to 1230° F; air cool to room temperature. Expected Brinell hardness 197 max.
4142 material is prehardened from the mill to a hardness of BHN 270/320 in thicknesses to 4" inclusive and BHN 260/310 in thicknesses over 4" to under 6" inclusive. CAUTION: 4142 material must be annealed prior to rehardening treatment to obtain a higher hardness. Heat treat the same as 4140.
No tempering is required, since the material is already prehardened at the mill. If the material is rehardened to obtain a higher hardness, the above tempering table may be used as a guide. Parts should be held a minimum of 1 hour per inch of thickness. A single temper is sufficient. However, since 1/2" dia. specimens were used for this test, it may be found that heavier sections are several points lower.