RPC钢激光焊接CGHAZ的组织与性能  

Microstructure and mechanical properties of laser welded CGHAZ of RPC steel

作　　者：赵琳[1] 张旭东[1] 陈武柱[1] 彭云[2] 田志凌[2] 

机构地区：[1]清华大学机械工程系,北京100084 [2]钢铁研究总院,北京100081

出　　处：《焊接学报》2005年第6期5-8,12,共5页Transactions of The China Welding Institution

基　　金：973国家重点基础研究规划项目(G1998061500)

摘　　要：利用Gleeble-1500热模拟机进行了激光焊接条件下热模拟试验,研究了弛豫-析出-控制相变钢激光焊接热影响区粗晶区(CGHAZ)组织和性能.结果表明,CGHAZ组织为粒状贝氏体,具有较高的硬度、强度.CGHAZ韧性随t8/5的增大先增大然后减小.当t8/5为3～8 s时,-40 ℃ CGHAZ冲击吸收功远高于母材的冲击吸收功,表明在合适的激光焊接条件下,激光焊接CGHAZ可获得很好低温韧性.CGHAZ韧性随热输入的变化主要是由M-A组元的尺寸、总量、数量和形状综合决定的.Relaxation-precipitation controlling transformation (RPC) steel is a kind of 800 MPa grade fine-grained steel. The microstructure and mechanical properties of the coarse-grained heat-affected zone (CGHAZ) in laser welding of RPC steel were investigated by simulation on a Gleeble-1500 thermal simulator. The experimental results indicate that the microstructure of the CGHAZ is granular bainite and the CGHAZ has higher hardness and tensile strength than the base metal. As cooling time from 800° to 500°C increases, the impact toughness of heat-affected zone increases at first and then decreases. The impact energy of the CGHAZ is much higher than that of base metal when cooling time from 800°C to 500°C is between 3 s and 8 s. It indicates that excellent low temperature toughness can be obtained under appropriate laser welding conditions. The variational trend of the impact toughness of the CGHAZ at different cooling time from 800°C to 500°C is mainly determined by the size, areal fraction, number and shape of the M-A ( M: martensite, A: austenite) constituent.

关 键 词：激光焊接 RPC钢 热膨响区粗晶区 组织 冲击吸收功 

分 类 号：TG456.7[金属学及工艺—焊接]