O1 Tool Steel

Chemical Analysis:
Carbon .85/1.00
Manganese 1.40/1.80
Phosphorus .030 Max.
Sulfur .030 Max.
Silicon .50 Max.
Chromium .40/.60
Vanadium .030 Max.
Tungsten .40/.60
Molybdenum -------
Cobalt -------
Tempering Temp. º(F): Hardness Rc
As-quenched 65.0
300 63.0
350 62.5
400 62.0
500 60.0
600 57.0
700 53.0
800 50.0
900 47.0
1000 44.0
1100 39.0
1200 31.0


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


Preheat to 1200° F and hold for uniformity.  Then raise to 1850° F - 1950° F.  Do not forge or roll below 1500° F, cool slowly from the forging or rolling temperature.  Do not normalize.


Heat slowly to 1450° F and soak thoroughly.  Furnace cool slowly at a rate of 20° F per hour to 900° F, remove and air cool.  Expected Brinell hardness 202 max.


Heat to 1475° F and hold 1/2 hour per inch of greatest thickness.  Large parts should be preheated at 1200° F and held for uniformity before raising to the hardening temperature. Oil quench 150° F and temper without delay.


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, but double tempering is a good insurance policy.  For most applications a tempering temperature of from 350° F - 450° F is usually specified for the O-1 analysis.  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.