D256耐磨堆焊接头组织与性能  

Research on microstructure and properties of D256 hardfacing joint

作　　者：王燕[1] 刘加伟[1] 

机构地区：[1]三峡大学机械与动力学院,湖北宜昌443002

出　　处：《电焊机》2015年第3期103-107,共5页Electric Welding Machine

摘　　要：采用D256耐磨焊条在Q235A钢基体上进行堆焊,研究不同焊接电流下D256堆焊接头组织和性能的变化。试验结果表明:采用D256耐磨焊条堆焊时,焊缝组织为奥氏体和渗碳体,电流较小时,焊缝组织是过饱和奥氏体,随着电流的增大,奥氏体晶粒增大,合金元素溶入,焊缝的硬度与耐磨性均降低。电流增大到140 A时,焊缝中的奥氏体晶粒最大,合金充分溶入奥氏体中,使得焊缝的硬度和耐磨性最低。电流较小时,焊接接头过热区的组织主要是晶粒较粗大铁素体、珠光体和魏氏组织的混合物,电流增大,晶粒增大,在电流140 A时过热区为粗大且明显的魏氏组织。正火区为比母材细小的铁素体和珠光体,堆焊层未出现裂纹,熔合良好,堆焊接头焊缝与HAZ硬度均高于母材,在100 A电流下得到组织和耐磨性能优良的堆焊层。Research on the variation regularity of nfcrostrtwtnre and properties of D256 surfacing joints under different welding currents in surlacing on Q235A with D256 wear resistance electro,de.The result shows that weld mierostrueture is austenite and eementite.The weld microstrt, c.ture is oversalurated austenite under lower eun＇ent anti austenite grain grows and alloy elements dissolve in with current increasing.Meanwhile,the hardness and wear resistance of wehl decrease as current enhancing.The maximum austenite grain in weht and sufficient dissolution of alloy elements in attstenite make Ihe hardness and wear resistance of weld are lowest at the current of 140 A.Under lower ~：urrenl ,microstrueture oF＇ overheated zone is mainly the mixture of coarse ferrite,pearlite and widnmnstatlen structure.The grain enlarges as current increasing.The microstrut.lure of overheated zone is coarse and obvious widmanstatten structure at the eurrent of 140 A.The mierostrueture of norumlized zone is ferrite and peadite which ate smaller than base metal.Surfacing layer has good fusion without crack.The hardness of the welds and HAZ of welded joints is higher than that of base metal.The microstructure and wear resistance are excellent at the current of 100 A.

关 键 词：表面堆焊 耐磨焊条 组织 硬度 耐磨性 

分 类 号：TG422.1[金属学及工艺—焊接]