装载机铲斗用550D高强钢焊接性能研究  

Research on Welding Properties of 550D High-strength Steel for Loader Bucket

作　　者：马蓉 廖国锋 苏雅萍 邹乃威 Ma Rong;Liao Guofeng;Su Yaping

机构地区：[1]广西柳工机械股份有限公司 [2]宁波工程学院机械工程学院,315336

出　　处：《工程机械》2021年第11期79-84,I0023,I0024,共8页Construction Machinery and Equipment

基　　金：国家自然科学基金资助项目(51775241)。

摘　　要：采用富氩焊方法,选择2种焊丝(ER50-6和ER60-G),分别对装载机铲斗用的8 mm板厚Q550D同种金属及异种金属(Q550D与Q345B)进行对接焊,分析了焊接接头的金相组织、拉伸和冲击性能以及硬度分布。结果表明:ER60-G与ER50-6焊缝组织均为先共析铁素体+侧板条铁素体+针状铁素体+少量珠光体,ER60-G的先共析铁素体比ER50-6的少,其抗拉强度和冲击韧性均比ER50-6高。Q550D热影响区粗晶区的组织为由贝氏体转变为侧板条铁素体+针状铁素体+均匀分散的细珠光体,其硬度比母材Q550D低。而Q345B热影响区粗晶区组织由条状铁素体+珠光体转变为分散均匀的块状铁素体+珠光体,其硬度比母材Q345B高。为提升装载机Q550D铲斗的可靠性,可优先考虑使用ER60-G焊丝焊接。With rich argon welding method,two kinds of electrodes(ER50-6 and ER60-G)are selected for butt welding of the same metal Q550D and dissimilar metals(Q550D and Q345B)with a thickness of8 mm for the loader bucket respectively,and metallographic structure,tensile and impact properties and hardness distribution of the welded joints are analyzed.The results show that the weld microstructures of ER60-G and ER50-6 are both proeutectoid ferrite+ferrite sideplate+acicular ferrite+a small amount of pearlite,and the proeutectoid ferrite of ER60-G is less than that of ER50-6,while its tensile strength and impact toughness are higher than that of ER50-6.The microstructure of Q550D coarse grained heat affected zone is ferrite sideplate+acicular ferrite+uniformly dispersed fine pearlite that are transformed from bainite,with lower hardness than base metal Q550D.However,the microstructure of Q345B coarse grained heat affected zone is uniformly dispersed granular ferrite+pearlite that are transformed from ferrite band+pearlite,with higher hardness than base metal Q345B.To improve the reliability of Q550D bucket of loader,ER60-G electrodes will take the priority.

关 键 词：装载机 Q550D钢 焊接 组织 力学性能 

分 类 号：TH243[机械工程—机械制造及自动化] TG457.11[金属学及工艺—焊接]