焊接热输入对纯铜焊缝组织及其力学性能的影响  

Influence of welding heat input on microstructure and mechanical properties of copper welded joint

作　　者：王磊[1] 卫国强[1] 高洪永[1] 姚健[1] 

机构地区：[1]华南理工大学机械与汽车工程学院,广东广州510640

出　　处：《焊接技术》2011年第8期10-14,79,共5页Welding Technology

基　　金：国家自然科学基金项目(50775003)

摘　　要：在纯铜(T2)钨极氩弧自动焊(TIG)条件下,研究了不同焊接热输入对焊缝成形、焊缝显微组织及力学性能的影响。结果表明:焊接热输入过大,焊缝正面出现咬边,焊缝反面过宽、余高过高,而焊接热输入过小焊缝未焊透,轧制时易出现根部裂纹;随着焊接热输入的增大,焊缝区以及热影响区晶粒尺寸都增大,接头塑性降低;焊后未轧制时,焊接热输入越大,接头强度越低,而轧制后,焊缝的抗拉强度没有明显的变化,焊接热输入小时的屈服强度明显高于焊接热输入大时的屈服强度,并且接头断裂均发生在焊缝熔合线区,说明熔合线区是整个焊接接头最为薄弱的环节。Influence of welding heat input on appearance,microstructure and mechanical properties of T2 copper welded joints which were welded by TIG automatic welding in the conditions of different welding heat input was investigated.The results showed that:1)When the welding heat input was excessive,undercutting will appear in the weld facade and the weld seam would be too wide,weld reinforcement would be too high in the reverse side.But too low welding heat input would result in incomplete penetration welding and root crack when rolling.2)With the increase of welding heat input,the grain size was increased in the weld zone and heat affected zone.This would reduce the plasticity of the welded joints.3)When the specimens were not rolled after welding,the greater the welding heat input,the lower the joints strength;there was no obvious difference in tensile strength after rolling,but the yield strength of lower welding heat input specimen was significantly higher than that of greater one.Weld seam fracture occurred in the weld fusion line area,indicating the fusion line area was the weakest part of welded joints.

关 键 词：纯铜焊接 TIG焊 焊接热输入 焊缝组织 力学性能 

分 类 号：TG457.13[金属学及工艺—焊接]