随焊冲击碾压整形对低匹配等承载接头硬度与残余应力的影响

随焊冲击碾压整形(weld shaping with trailing impact rolling,WSTIR)是一种能够降低应力变形、提高承载能力的随焊整形新方法.分别对原始焊态的低匹配等承载接头与随焊冲击碾压整形的低匹配等承载接头进行了硬度试验和残余应力试验.结果表明,随焊整形等承载接头焊缝表面、焊趾处表面的硬度显著高于原始焊态等承载接头的硬度,说明随焊冲击碾压整形对接头承载的关键区域有加工硬化的效果；随焊整形低匹配等承载接头各点的纵向和横向残余应力明显低于原始焊态等承载接头相应位置的纵向和横向残余应力,甚至在随焊整形接头的焊缝中心以及焊趾附近纵向均出现了残余压应力,残余压应力的引入必然能显著地提高低匹配接头承载能力.

Influence of weld shaping with trailing impact rolling on hardness and residual stress of under-matched equal loadcarrying joint

Weld shaping with trailing impact rolling (WSTIR) is a new weld shaping and modifying technique to reduce the residual stress and distortion and improve load-carrying capacity of under-matched joint. Vickers hardness test and residual stress test were carried out for under-matched equal load-carrying joint in as-welded state and after WSTIR,respectively. Hardness test results show that the surface hardness,both on weld beam and weld toe,for equal load-carrying joint after WSTIR was significantly higher than that in as-welded state, which revealed that WSTIR had work-hardening effect on key load-carrying areas for equal load-carrying joint. Residual stress test results show that both longitudinal and transverse residual stresses on under-matched joint after WSTIR were remarkably lower than those in as-welded state. Especially,longitudinal compressive residual stress appeared in the weld beam and weld toe after WSTIR,which can undoubtedly improve the load-carrying capacity for under-matched joint.