堆焊工艺对曲轴轴颈堆焊合金组织性能的影响  

The Effect of Surfacing Process on Microstructure and Properties of Crankshaft Journal Surfacing Alloy

作　　者：王守忠[1] 朱凯[1] 刘玉莹[1] WANG Shouzhong;ZHU Kai;LIU Yuying(Shangqiu Polytechnic,Shangqiu 476100,China)

机构地区：[1]商丘职业技术学院,河南商丘476100

出　　处：《商丘职业技术学院学报》2020年第5期73-78,共6页JOURNAL OF SHANGQIU POLYTECHNIC

基　　金：2019年度河南省高等职业院校创新发展行为计划项目(任务)“汽车与维修技术”(XM-01骨干专业)。

摘　　要：为了减少堆焊曲轴变形,提高焊层的均匀性,取消焊后热处理工序,将被再制造的曲轴安装在改装后的专用车床上,利用电焊机采用明弧堆焊的方法在曲轴轴颈表面堆焊Fe-Cr-C-B合金层.采用SEM(附带EDS)、XRD和硬度计等,观察并测试了焊后空冷和快冷堆焊合金的组织结构和性能.结果表明:空冷堆焊合金的表面硬度为62 HRC,冲击韧性为6.8 J/cm^-2,组织由板条马氏体+残余奥氏体基体和(Fe,Cr)2(B,C)、(Fe,Cr)3(B,C)、(Fe,Cr)23(B,C)6硼碳化物组成;快冷堆焊合金组织较空冷减少了(Fe,Cr)3(B,C)物相,表面硬度提高了5 HRC,冲击韧性提高了6.4 J/cm^2.台架试验结果表明,空冷和快冷再制造曲轴的耐磨性,相对于原装曲轴分别提高了25%和50%.研制的自保护药芯焊丝和堆焊工艺性价比良好,值得借鉴.In order to reduce the deformation of the surfacing and improve the uniformity of the welding layer,the postweld heat treatment process is eliminated.The remanufactured crankshaft will be installed in the modified special lathe,using the electric welder and open arc surfacing method to Fe-Cr-C-B alloy layer on the surface of the crankshaft journal.The microstructure and properties of air cooling and rapid cooling surfacing alloy after welding were observed and tested by SEM(with EDS),XRD and hardness tester.The results show that the surface hardness of the air-cooled surfacing alloy is 62 HRC and the impact toughness is 6.8 J/cm^2,and the micro structure consists of lath marten-site+retained Austerlitz matrix and(Fe,Cr)2(B,C),(Fe,Cr)3(B,C),(Fe,Cr)23(B,C)6 carbide composition;The microstructure of the rapid cooling surfacing alloy decreases the(Fe,Cr)3(B,C)phase and increases the surface hardness by 5 HRC.The bench test results show that the wear resistance of the crankshaft repaired with air cooling and rapid cooling is increased by 25%and 50%respectively compared with the original crankshaft.The developed surfacing flux cored wire and process are cost-effective and worth learning.

关 键 词：曲轴 专用车床 Fe-Cr-B-C 堆焊工艺 耐磨性 

分 类 号：TG422[金属学及工艺—焊接]