大截面新型预硬型塑料模具钢SDP1Cu的时效析出强化机制  

Aging Precipitation Strengthening Mechanism of Large Section New Prehardened Plastic-Working Die Steel SDP1Cu

作　　者：李志 陈旋[1,2] 吴晓春 LI Zhi;CHEN Xuan;WU Xiaochun(College of Materials Science and Engineering,Shanghai University,Shanghai 200444,China;State Key Laboratory of Advanced Special Steel,Shanghai University,Shanghai 200444,China;Shangda Xinlun Material and Technology(Shanghai)Co.,Ltd,Shanghai 201999,China)

机构地区：[1]上海大学材料科学与工程学院,上海200444 [2]上海大学省部共建高品质特殊钢冶金与制备国家重点实验室,上海200444 [3]上大鑫仑材料科技(上海)有限公司,上海201999

出　　处：《机械工程材料》2022年第5期28-35,共8页Materials For Mechanical Engineering

基　　金：国家重点研发计划项目(2016YFB0300404)。

摘　　要：在固溶处理时采用油冷和缓冷两种冷却方式来模拟得到大截面新型预硬型塑料模具钢SDP1Cu的表面和心部组织,研究了不同时效处理(350~600℃保温1~20 h)对组织与硬度的影响,并通过电阻法和熟化理论探讨了时效析出强化机制。结果表明:随着时效温度的提高和时间的延长,油冷后马氏体组织和缓冷后贝氏体组织逐渐分解直至消失,渗碳体颗粒弥散分布在铁素体基体上;在500℃时效2~20 h后,油冷和缓冷钢的硬度差在0.5 HRC之间,截面硬度均匀性良好;富铜析出相在高于400℃后开始析出,随着时效温度升高,析出相尺寸增大,析出强化机制由模量强化和共格强化相结合的位错切过机制转变为位错绕过机制。During solution treatment, two cooling methods, oil cooling and slow cooling, were used to simulate the surface and core microstructures of a large section new prehardened plastic-working die steel SDP1 Cu. The effects of different aging treatments(350-600 ℃ for 1-20 h) on the microstructure and hardness were studied, and the aging precipitation strengthening mechanism were discussed by resistance method and aging theory. The results show that with increasing aging temperature and time, the oil-cooled martensite and slow-cooled bainite structure gradually decomposed and finally disappeared, and cementite particles were dispersed on ferrite matrix. After aging at 500 ℃ for 2-20 h, the hardness difference between oil-cooled and slow-cooled steels was within 0.5 HRC, and the cross-section hardness uniformity was good. The copper-rich precipitates started to precipitate when the temperature was higher than 400 ℃. With increasing aging temperature, the size of precipitates increased, and the precipitation strengthening mechanism changed from dislocation cutting mechanism combining modulus strengthening and coherence strengthening to dislocation bypassing mechanism.

关 键 词：热处理 塑料模具钢 析出相 强化机制 

分 类 号：TG156.5[金属学及工艺—热处理]