【摘要】 研究了冷作模具钢６５Ｎｂ经高温固体渗碳后采用淬火加多次回火，及不同时间等温淬火后的组织分布及硬度分布，同时对６５Ｎｂ钢５５０℃低温渗碳后的组织及硬度进行了分析结果表明，６５Ｎｂ钢经渗扩碳复合强韧化后，由表面至心部存在硬度梯度，并于一定深度出现峰值，对于提高模具钢的耐磨性和抗脆断能力具有重要意义；低温渗碳可实现无形变地达到表面强化更多还原

【Abstract】 The distribution of hardness and microstructure of Cold die steel is studied after carburizing of high temperature hardening and tempering many times and isothermal hardening with different time.The distribution of hardness and microstructure is also analysed after carburizing of low temperature(550℃) The results show that there is a gradient and a peak of hardness after composite strenthening and toughening.It is important that the wear-resistant and brittle fracture of cold die steel are improved.Carburizing of low temperature can be used and not results change of shape,and the process is easy.更多还原