Cr3型压铸模具钢4Cr3Mo2V的CCT和TTT曲线  

CCT and TTT curves of Cr3 type die casting steel 4Cr3Mo2V

作　　者：李玲 吴晓春[1,2] Li Ling;Wu Xiaochun(School of Materials Science and Engineering,Shanghai University,Shanghai 200072,China;State Key Laboratory of Advanced Special Steel,Shanghai University,Shanghai 200072,China)

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

出　　处：《金属热处理》2023年第4期10-18,共9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(SKLASS2020-Z08)。

摘　　要：利用DIL805A淬火变形膨胀仪对新型Cr3型热作模具钢4Cr3Mo2V进行过冷奥氏体连续冷却转变和过冷奥氏体等温转变试验,研究了冷却速度对相变组织和硬度的影响,绘制了Cr3钢的CCT曲线和TTT曲线,并与Cr5型4Cr5Mo2V钢的CCT曲线和TTT曲线进行对比。结果表明,Cr3钢的Ms=320℃,Ac1=795℃,Accm=895℃。当Cr3钢以不同速度连续冷却时,分别出现了珠光体转变、贝氏体转变和马氏体转变。与Cr5钢相比,Cr3钢的CCT曲线左移,淬透性降低。Cr3钢的TTT曲线呈“双C型”,贝氏体转变区的温度范围在320~410℃,珠光体转变区的温度范围在650~750℃,“鼻尖”温度出现在715℃左右,珠光体转变结束所需时间为17 882 s。Continuous cooling transformation and isothermal transformation tests were carried out on new Cr3 type hot working die steel 4Cr3Mo2V by DIL805A quenching deformation dilatometer.The effect of cooling rate on the phase transformation and hardness was studied.The CCT curves and TTT curves of the Cr3 steel were drawn and compared with those of Cr5 type steel 4Cr5Mo2V.The results show that for the Cr3 steel,its Ms=320℃,Ac1=795℃,Accm=895℃.When continuous cooling with different speeds,pearlite transformation,bainite transformation and martensite transformation appear in the Cr3 steel respectively.Comparing with the Cr5 steel,the CCT curves of the Cr3 steel shifts to the left and the hardenability decreases.The TTT curves of Cr3 steel is double-C type,the temperature range of bainite transformation zone is 320-410℃,the temperature range of pearlite transformation zone is 650-750℃,where the“nose tip”temperature appears at about 715℃,and the time required for the end of the pearlite transformation is 17882 s.

关 键 词：CCT曲线 TTT曲线 显微组织 硬度 铬元素 

分 类 号：TG142.45[一般工业技术—材料科学与工程]