压铸模具钢大模块真空高压气淬冷却过程的数值模拟  

Numerical simulation of vacuum high-pressure gas quenching cooling process for large die-casting die steel modules

作　　者：蒋志鹏 陈浩[1] 吴晓春[1] Jiang Zhipeng;Chen Hao;Wu Xiaochun(State Key Laboratory of Advanced Special Steel,School of Materials Science and Engineering,Shanghai University,Shanghai 200072,China)

机构地区：[1]上海大学、材料科学与工程学院、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

出　　处：《金属热处理》2023年第4期211-220,共10页Heat Treatment of Metals

基　　金：广东省重点领域研发计划(2020B010184002);省部共建高品质特殊钢冶金与制备国家重点实验室自主课题项目(SKLASS2020—Z08)。

摘　　要：以尺寸为500 mm×500 mm×500 mm的SDDVA模具钢大模块为研究对象,采用DEFORM建立模块真空气淬冷却过程的数值模型,结合试验研究了大模块在真空气淬炉中不同淬火压力条件下的冷却行为、组织演变及应力演变规律,并从理论角度预测了模块可生产的最大规格。结果表明,大模块心部在0.4、0.6和0.9 MPa压力条件下气淬,均观察到先共析碳化物沿晶析出。为了避免碳化物沿晶析出,从800℃冷却到500℃的冷速应不小于0.25℃/s。0.4 MPa压力条件下气淬过程中,模块最大心表温差最小,约为120℃;大模块心部在0.9 MPa压力条件下淬火所得马氏体含量高于0.4、0.6 MPa压力下淬火,同时,贝氏体含量也更少;模块表面和心部主要表现为热应力和组织应力。SDDVA钢模块在0.4、0.6和0.9 MPa压力条件下真空高压气淬可生产的理论最大厚度分别为280、320和380 mm。A numerical model of vacuum gas quenching cooling process of a 500 mm×500 mm×500 mm SDDVA die steel module was investigated by using DEFORM to investigate the cooling behaviour,microstructure evolution and stress evolution of the large module under different quenching pressure conditions in a vacuum air quenching furnace,and to predict the maximum size of the module that can be produced from a theoretical point of view.The results show that the proeutectoid carbide precipitation along the crystal is unavoidable in large module cores when quenched under 0.4,0.6 and 0.9 MPa.And in order to avoid carbide precipitation,the cooling rate from 800℃to 500℃should be at least greater than 0.25℃/s.When gas quenched under pressure of 0.4 MPa,the maximum temperature difference between the core and the surface of the module is the smallest,about 120℃.The martensite content obtained in the core of large modules quenched under 0.9 MPa is higher than that obtained by quenching under 0.4 and 0.6 MPa,and the bainite content is also lower.The surface and core of the module mainly exhibit thermal and phase transformation stresses.The theoretical maximum thickness of SDDVA modules quenched by vacuum and high pressure gas under 0.4,0.6 and 0.9 MPa is 280,320 and 380 mm,respectively.

关 键 词：数值模拟 大模块 气淬 组织演变 压铸模具钢 

分 类 号：TG161[金属学及工艺—热处理]