工程机械用960QT钢焊接粗晶区组织及性能研究  

Study on Structure and Performance of Coarse Grained Heat Affected Zone(CGHAZ) of Machinery Steel 960QT

作　　者：刘旭辉[1,2] 张波 肖爱达[2] 欧玲 郝春晖 Liu Xuhui;Zhang Bo;Xiao Aida;Ou Ling;Hao Chunhui(The State Key Lab of Rolling and Automation of Northeastern University,Shenyang 11004;School of Metallurgical Engineering,Hunan University of Technology,Zhuzhou 412000;Technical Center,Hunan Hualing Lianyuan Iron & Steel Co.,Ltd.,Loudi 417009)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,沈阳110004 [2]湖南华菱涟源钢铁有限公司技术中心,娄底417009 [3]湖南工业大学冶金与材料工程学院,株洲412000

出　　处：《特殊钢》2019年第1期63-67,共5页Special Steel

摘　　要：采用热模拟技术研究了960QT高强钢不同t_(8/5)条件下热影响区粗晶区(CGHAZ)的组织和性能,获得热影响区连续冷却转变曲线。得到的结果为:t_(8/5)在3～6s,硬度值变化不大,CGHAZ组织为板条马氏体。t_(8/5)=10 s,可见板条贝氏体,随着t_(8/5)的增加,组织中板条贝氏体逐渐增加,而板条马氏体逐渐减少,CGHAZ显微硬度逐渐降低。当t_(8/5)达到150 s后,组织中出现粒状贝氏体,显微硬度进一步降低。当t_(8/5)> 600 s后,显微组织以粒状贝氏体为主。利用实测热影响区t_(8/5)数据,建立了960QT钢t_(8/5)值与线能量(E)的关系式。t8/5为30 s时,粗晶区显微硬度(325 HV1)与母材相当(330 HV1)。焊接时应控制热输入,使t_(8/5)小于30 s,不预热条件下线能量应小于1.4kJ/mm。The microstructure and property of the coarse grained heat affected zone( CGHAZ) of 960 QT steel was studied under t8/5 by using thermal simulation technology, and the continuous cooling transformation curve of the heat affected zone(SH-CCT diagram) was acquired. The results show that, the microstructure of the CGHAZ consists of lath martensite and the hardness values change little as t8/5 is 3~6 s. When t8/5=10 s, lath bainite appears. With the increase of t8/5, the lath martensite reduces and lath bainite increases, and the microhardness of CGHAZ gradually reduces. When t8/5 reaches150 s, granular bainite in structure is found the microhardness is further reduced. As t8/5 >600 s, the CGHAZ mainly consists of granular bainite. Based on the measured heat affected zone t8/5, the relationship between t8/5 values and heat input E of steel 960 QT is established. As t8/5 is 30 s, the microhardness of CGHAZ(325 HV1) is equal to the base metal(330 HV1). So the heat input should be controlled to ensure that t8/5 is less than 30 s. Under non-preheating conditions, the heat input should be less than 1.4 kJ/mm.

关 键 词：960QT钢 焊接热模拟 热影响区粗晶区 显微组织 硬度 

分 类 号：TG457.11[金属学及工艺—焊接]