O6 Tool Steel

Chemical Analysis:
Carbon 1.25/1.55
Manganese .30/1.10
Phosphorus .030 Max.
Sulfur .030 Max.
Silicon .55/1.50
Chromium 30 Max.
Vanadium -------
Tungsten -------
Molybdenum .20/.30
Cobalt -------
Tempering Temp. º(F): Hardness Rc
As-quenched 65.0
300 62.0
400 61.0
500 60.0
600 58.0
700 54.0
800 50.0
900 47.0
1000 40.0
1100 37.0
1200 26.0

Uses:

Punches, dies, trim dies, blanking dies, forming dies, stamping dies.

Forging/Rolling:

Preheat to 1300° F and soak thoroughly.  Then raise temperature and forge or roll to 2000° F max.  Do not forge or roll below 1700° F, cool slowly from the forging or rolling temperature.  Do not normalize.

Annealing:

Heat slowly to a range of 1425° F - 1450° F and soak thoroughly.  Furnace cool slowly to 1000° F, remove and air cool.  Expect Brinell hardness 217 max.

Hardening:

Preheat at 1250° F and soak thoroughly, then heat to 1450° F - 1500° F, and hold 1 hour per inch of greatest thickness.  Oil quench to 150° F and temper without delay.

Tempering:

Temper before the parts have cooled to below 150° F.  Small parts should be held a minimum of 1 hour per inch of greatest thickness and large parts 2 hours per inch of greatest thickness.  A single temper is sufficient.   For the majority of tooling work tempering at 300° F - 400° F is satisfactory.  The following 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.