L6 Tool Steel
|Tempering Temp. º(F):||Hardness Rc|
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.