1 results about "Hot work" patented technology

Disclosed is a tempering method to yield hot work tool steel with high toughness. Disclosed is a method for tempering hot work tool steel made from, by mass %, C: 0.32-0.45%, Si: 0.01-0.8% or less, Mn: 0.1-0.8%, Ni: 0-0.8% or less, Cr: 4.5-5.6%, Mo and W, singly or in composition (Mo+1/2W): 2.0-3.5%, V: 0.5-1.0%, Co: 0-2.0%, and the remainder Fe and inevitable impurities, wherein which steel tempering method performs rapid cooling at a fast rate of 80 minutes or less from a 1020-1070°C tempering temperature to 530°C. Preferably, the steel tempering method, after rapid cooling at the fast rate described above, then performs cooling at a slower rate of 60-250 minutes to 150°C.