Research On Weldability And Friction Stir Welding Procedure Of Spray Forming7055Aluminum Alloy

In this research, the weldability of spray forming7055aluminum is evaluated byfish-bone-like crack experiment. Spray forming7055aluminum alloy were weld by FSWand laser welding. Then the effect of different heat treatment state on properties of FSWwere studied and the relationship between organization, performance and heat treatmentstate after laser welding were looked into briefly. The results show that, the weld wouldcrack to serious degree, nearly20%, when using S311as filler wire. When replacing S311with S331, crack resistance had improved and the crack-splitting degree came to be12%.Crack-splitting degree had reached the lowest value,8%,when using spray forming7055aluminum alloy as filler wire. When7055aluminum alloy under spray forming state wereFSW at a rotation speed of1000rpm and travel speed of100mm/min, the weld can get themost reasonable properties with a tensile strength of286MPa. After postweld heat treatment,an ultimate strength of the joints up to453.4MPa which is64.1%of the base material isobtained. Heat treatment improve the strength and hardness of weld. But the strength is stillnot ideal because the weld metal grain grow up during recovery and recrystallization and themirco-defect sensitivity of weld is improved. The strength of FSW weld of spray forming7055after solution treatment is429.19MPa, and it is60.7%of base material. Obviously, thewelding joint become the softened zone. That is because second phase particle dissolvinginto base material reduced the strength of weld. Laser welding with reasonable parameterscan weld Spray forming7055aluminum alloy well.. The appearance of weld is fine withnarrow weld width. It can realize weld without welding material but it would leave sag onthe weld surface easily. The weld without heat treatment obtained under laser power7.5KWand travel speed of4m/min can get the strength of243MPa. It is66.4%of base material. Ifgiving heat treatment to the weld, the strength would be up to483MPa, that is68.3%ofbase material. There exist some stomata and inclusions in the weld. The strength of weldwhich is relatively low is due to burning-off of the alloying elements for no use of weldmaterial.