Vacuum heat treatment furnace was used to test the dimensional distortion rate of SLD-MAGIC and DC53 cold working die steel specimens under three heat treatment conditions of quenching at 1030 ℃,tempering at 210 ℃ and tempering at 520 ℃,and combined with X-ray diffractometer(XRD),scanning electron microscope(SEM),high-precision differential dilatometer,JMatPro software to analyze the microstructure,characteristic parameters of martensite,the content of retained austenite and the content of secondary carbides.The results show that the volumes of the SLD-MAGIC and DC53 steel specimens expand after the three heat treatments,and their dimensional distortion rates range from 0.02％to 0.12％.The average dimensional distortion rate of the DC53 steel is about 1.9 to 2.2 times that of the SLD-MAGIC steel under the same heat treatment conditions.The average thermal expansion coefficient of the SLD-MAGIC steel from 25 ℃ to 700 ℃ is 0.15 × 10-6 ℃-1 lower than that of the DC53 steel,the carbon content and lattice constant of the martensite of the SLD-MAGIC steel are 1.34％and 2.8894 × 10-10 m,respectively,which are smaller than that of the DC53 steel.The content of retained austenite and the content of secondary carbide of SLD-MAGIC steel after heat treatment are less than that of the DC53 steel.Therefore,the size expansion effect of the SLD-MAGIC steel is smaller than that of the DC53 steel,and the SLD-MAGIC steel has the characteristic of heat treatment microdistortion.
SLD-MAGIC cold working die steelheat treatment microdistortionmartensiteretained austenitecarbide in tempering
NETL
NSTL
万方数据
