4140 Annealed Tool Steel

Chemical Analysis:

Carbon

.36/.44

Manganese .70/1.10
Phosphorus .035 Max.
Sulfur .040 Max.
Silicon .15/.35
Chromium .75/1.20
Vanadium -------
Tungsten -------
Molybdenum .15/.25
Cobalt -------
Tempering Temp. º(F): Hardness Rc
As-quenched 60.1
400 57.8
500 53.4
600 49.5
700 46.1
800 42.9
900 38.8
1000 34.1
1100 31.1
1200 27.7
1300 23.5

Uses:

Brake die, support tooling, die holders, short run stamping and bending dies.

Forging/Rolling:

Heat slowly and uniformly to a temperature of from 1800° F to 2000° F.  Do not forge or roll below 1600° F.

Annealing:

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.

Hardening:

Heat to 1500° F - 1600° F and hold 1/2 hour per inch of greatest thickness.  Quench into 150° F oil.

Tempering:

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.