L6 Tool Steel

Chemical Analysis:
Carbon .65/.75
Manganese .25/.80
Phosphorus .030 Max.
Sulfur .030 Max.
Silicon .50 Max.
Chromium .60/1.20
Vanadium -------
Tungsten -------
Molybdenum .50 Max.
Nickel 1.25/2.00
Tempering Temp. º(F): Hardness Rc
As-quenched 65.0
300 62.0
400 61.0
500 58.0
600 56.0
700 53.0
800 50.0
900 48.0
1000 46.0


Form rolls, stamping dies, forming dies, shear blades, punches, trimmer dies, pawls, knuckle pins, spindles, clutch pins.


Heat slowly and uniformly to a temperature of from 2100° F - 2175° F.  Do not forge or roll below 1700° F, cool slowly from the forging or rolling temperature.  Do not normalize.


Heat slowly to 1400° F, and hold for 1 hour per inch of thickness.  Furnace cool at 20° F per hour to 900° F; air cool to room temperature.  Expected Brinell hardness 217 max.


Preheat to 1200° F - 1400° F depending on the section size soak until uniformly heated, and either transfer or raise furnace temperature to 1500° F - 1550° F, and hold 1 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 2 hours per inch of greatest thickness.  A single temper is sufficient, but double tempering is a good insurance policy.  For most applications the tempering temperature of 400° F is recommended, but since L-6 does not become brittle like other steels, when tempered in 450° F - 800° F range, it may be tempered at a higher temperature where greater toughness is required.  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.