25CrMo与Q345D焊接裂纹敏感性研究  

Crack susceptibility in welding of 25CrMo and Q345D

作　　者：李雪东 连军 马振[2] 尹柯[2] 李慕勤[2] 

机构地区：[1]佳木斯电机股份有限责任公司,154002 [2]佳木斯大学教育部金属耐磨材料及表面工程研究中心,154007

出　　处：《焊接》2012年第8期34-37,70,共4页Welding & Joining

摘　　要：针对风力发电机轴与辐板焊接,提出采用25CrMo作为电机轴,Q345D作为辐板,研究两种材料的焊接性问题。计算25CrMo和Q345D的C_(eq)分别为0.65%和0.45%,说明25CrMo的焊接性较差,制订了焊前预热温度为250℃,层间温度不低于预热温度,550℃×3 h焊后热处理缓冷的焊接工艺。采用MAG焊方法,选用ER49-1、ER55-G、ER50-6三种焊丝,在相同焊接工艺下进行焊接,通过斜Y型坡口焊接裂纹试验方法评定焊接裂纹率。试验结果表明,三种焊丝焊接焊缝表面均未有裂纹产生,断面裂纹产生在25CrMo与焊缝界面及两种母材的热影响区粗晶区,尤其是25CrMo粗晶区在焊后热处理时,造成裂纹进一步扩展,产生再热裂纹。焊接轴材料25CrMo和辐板Q345D选用ER55-G最优,其次也可选用ER50-6和ER49-1。The welding of 25CrMo motor shaft and Q345 radial plate used for wind-power generators was studied.The carbon equivalent of 25CrMo and Q345D are 0.65%and 0.45%,respectively,which leads to the poor weldability of the 25CrMo.The welding parameters were determined,which includes 250℃of preheating temperature,interpass temperature higher than preheating temperature,550℃×3 h of post heat treatment and slow cooling after welding.During the metal active-gas welding,the ER49 - 1,ER55 - G,ER50 -6 welding wires was used with the same welding parameters.Through oblique Y-groove test,the welding crack ratio was elevated.The results showed that the crack is not found on the surface of the weld with the above-mentioned welding wires,and the cross crack appears in the interface between the 25CrMo and the weld metal or in the coarse crystal zone of the heat-affected zone.Especially for the 25CrMo,the crack will expand in the coarse zone during the post weld treatment.The best suitable welding wire should be ER55 - G,and the ER50 - 6 or ER49 - 1 also can be used for welding.

关 键 词：裂纹 焊接性 硬度 金相组织 

分 类 号：TG406[金属学及工艺—焊接]