5CrMnMo钢淬火加热保温时间的研究

Research on Holding Time at Austenitizing Temperature for 5CrMnMo Steel

研究了５ＣｒＭｎＭｏ钢在９００℃下的加热淬火保温时间对组织和力学性能的影响。结果表明，随保温时间的延长，淬火组织中针状马氏体减少，板条马氏体和残留奥氏体增加。当保温时间超过３５ｍｉｎ后，淬火组织由单一板条马氏体和包围在板条马氏体周围的残留奥氏体薄膜组成。保温时间不超过９０ｍｉｎ，σｓ和σｂ值不下降。经５２０℃和５４０℃回火，αＫ值与ＫＩＣ值在５０ｍｉｎ保温时出现明显峰值，适当的淬火保温时间是提高５ＣｒＭｎＭｏ热作模具钢韧性的重要工艺措施。

Effect of the holding time at 900℃ on the microstructure and mechanical properties of steel 5CrMnMo has been studied Results show that with the holding time increasing,acicular martensite decreases in the quenched structure,while lath martensite and residual austenite increase When holding time exceeds 35 min,quenched structure consists of single lath martensite,with the film of residual austenite surrounding Values of σ s and σ b will not decrease unless holding time surpasses 90 min When held 50 min at the austenitizing temperature and then tempered at 520℃ and 540℃, α K value and K IC value have apparent peaks Modest holding time is an important process to enhance the ductility of hot die steel 5CrMnMo