下限温度对4Cr5Mo2V钢热机械疲劳行为的影响  

Effect of lower limit temperature on thermo-mechanical fatigue behavior of 4Cr5Mo2V steel

作　　者：顾鹏程 吴博雅 吴晓春[1,2] Gu Pengcheng;Wu Boya;Wu Xiaochun(State Key Laboratory of Advanced Special Steel,Shanghai University,Shanghai 200072,China;School of Materials Science and Engineering,Shanghai University,Shanghai 200072,China)

机构地区：[1]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200072 [2]上海大学材料科学与工程学院,上海200072

出　　处：《金属热处理》2024年第12期206-213,共8页Heat Treatment of Metals

基　　金：国家重点研发计划(2016YFB0300404);省部共建高品质特殊钢冶金与制备国家重点实验室资助课题(SKLASS2019-Z016)。

摘　　要：通过改变循环下限温度,在不同温度范围内(100~600、160~600、200~600和300~600℃),使用MTS热机械疲劳液压伺服试验机进行热机械疲劳(Thermal mechanical fatigue,TMF)试验,研究了4Cr5Mo2V热作模具钢的热机械疲劳行为,并通过超景深显微镜、光学显微镜(OM)和扫描电镜(SEM)分析了TMF试验后试样表面宏观形貌和微观组织的变化。结果表明,试验钢的热机械疲劳滞后回线具有明显的不对称性;下限温度越低,滞后回线包围的面积越大,其疲劳寿命越短;温度范围越大,主裂纹的宽度越大,扩展路径越曲折,损伤越严重。随着下限温度的增加,试验钢中的马氏体以及碳化物粗化程度增大,当温度范围为300~600℃时,受到温度循环和机械循环的持续作用时间更长,马氏体板条粗化及碳化物析出粗化现象更严重。Thermo-mechanical fatigue behavior of 4Cr5Mo2V hot work die steel was studied by changing the cycle lower limit temperature in different temperature ranges(100-600,160-600,200-600 and 300-600℃)using MTS thermo-mechanical fatigue hydraulic servo machine.The macro morphology and microstructure of the TMF specimens were analyzed by ultra depth of field microscope,optical microscope(OM)and scanning electron microscope(SEM).The results show that the thermo-mechanical fatigue lag loop of the tested steel has obvious asymmetry.The lower the lower limit temperature,the larger the area enclosed by the hysteresis loop,and the shorter its fatigue life.The larger the temperature range,the larger the width of the main crack,the more tortuous the propagation path and the more serious the damage.With the increase of lower limit temperature,the coarsening degree of martensite and carbide in the tested steel increases.When the temperature range is 300-600℃,the continuous action time of temperature cycle and mechanical cycle is longer,and the coarsening phenomenon of martensite laths and carbide precipitation is more serious.

关 键 词：热作模具钢 热机械疲劳行为 下限温度 显微组织 

分 类 号：TG142.1[一般工业技术—材料科学与工程]