4140 Annealed 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 1800° F to 2000° F. Do not forge or roll below 1600° F.
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.
Heat to 1500° F - 1600° F and hold 1/2 hour per inch of greatest thickness. Quench into 150° F oil.
Temper immediately after quenching, before part has cooled to below 150° F. Parts should be held a minimum of 1 hour per inch of thickness. A single temper is sufficient. The above tempering table may be used as a guide. However, since 1/2" dia. specimens were used for this test, it may be found that heavier sections are several points lower.