Effect of heat treatment process on heat treatment deformation of three different Cr series cold working die steels
The deformation caused by large cyclic loads during the service process of precision stamping molds will increase their maintenance costs and shorten their lifespan.Taking into account the deformation factors generated during the heat treatment of precision molds,the volume expansion caused by phase transformation is of greater concern.A new type of"well"shaped deformation module was designed,and the size changes caused by phase transformation of D2,DC53 and 7Cr5Mo2V three cold working die steels under different vacuum heat treatment processes were studied.The results show that after quenching at 1030 ℃,the maximum deformation rate of the DC53 steel is about 0.65％.After low-temperature tempering at 210 ℃ and high-temperature tempering at 520 ℃,the maximum deformation rates of the 7Cr5Mo2V steel are about 1.04％and 1.81％,respectively.The factors that affect the deformation of the mold during heat treatment are the retained austenite content,the amount of secondary carbide precipitation and the characteristic parameters of martensite.After low-temperature tempering at 210 ℃,the volume fractions of the retained austenite in the 7Cr5Mo2V,D2 and DC53 steels are 14.44％,13.21％and 11.43％,respectively.After high-temperature tempering at 520 ℃,the volume fractions of the retained austenite significantly decrease,which are 6.04％,3.39％and 2.53％,respectively.
cold working die steel"well"shaped moduleheat treatment deformationretained austenite
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