Fiber Laser Welding of AlSiCoated PressHardened Steel
Fiber Laser Welding of AlSiCoated PressHardened Steel
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发表时间：
2016
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通讯作者：
D. Saha;E. Biro;A. Gerlich;Y. Zhou
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文献类型：
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作者：
D. Saha;E. Biro;A. Gerlich;Y. Zhou
本文研究了Al-Si涂层对光纤激光焊接压力硬化钢的组织和性能的影响。结果表明，Al-Si涂层的混合显著改变了熔合区的组织，在焊接时和热冲压状态下，熔合区组织均为马氏体和三角洲铁素体的组合。相反，在焊接和热冲压时，观察到α铁素体和马氏体相的均匀分布。发现铁素体相富含Al和Si，延缓了马氏体相的形成动力学，增加了热冲压后的铁素体含量。铁素体的显微和纳米硬度测量表明，与马氏体相相比，铁素体是一个较软的相；因此，在拉伸试验中会发生应变局部化和过早断裂。全焊接接头的强度依赖于铁素体相分数，因为这促进了早期断裂，并降低了接头的强度和塑性。
The effect of an AlSi coating on the microstructure and mechanical properties of fiber laserwelded, presshardened steel is examined in the present work. It is shown that mixing of the AlSi coating significantly modified the fusion zone microstructure, which was found to be a combination of martensite and delta ferrite in both the welded asreceived and hotstamped conditions. In contrast, a uniform distribution of alpha fer rite and martensite was observed when the asreceived sheet was welded then hot stamped. The ferrite phase was found to be rich in Al and Si, which retarded the kinetics of martensite formation, increasing the ferrite fraction after hot stamping of the welded coupon. Micro and nanoscale hardness measurements on ferrite suggest it is a softer phase compared to martensite; therefore, inducing strain localization and premature fracture during tensile tests occurred. The strength of allwelded joints was found to be dependent on ferrite phase fractions, since this promoted premature fracture, and dete riorated joint strength and ductility.