Research On Heat Treatment Technology And Weldability Of Almgsi Base Alloy Plates

Based on the composition of6000Al-based alloy plates, a new type of vehiclealuminum plates with erbium was analyzed. The effect of the rolling process on structureand properties of alloy plates was studied, the heat treatment process of aluminum alloyplates containing erbium was optimized, meanwhile, the welding process of the plates wasstudied.It has a deeper insight of the change of grains during rolling process though observing.The change rules of grains during hot rolling and cold rolling was analyzed：the grain willgrowth after the hot rolling because of the dynamic recovery and dynamic recrystallization.Most of the grains are like fibrous, which were flattened in the perpendicular to the rollingdirection and elongated in rolling direction simultaneously. The grains will be flattened incold rolling, meanwhile the grains will be broken during excessive deformation, whichmeans the grains become smaller. The grains are flattened and elongated in rollingdirection at the same time. The methods of rolling processing make the grains directional,which can result in anisotropy plates.After the solution treatment at540℃for1hour and180℃artificial aging for5hours，the maximum of tensile strength was395MPa and the elongation was21.6%，which is thebest heat treatment process for the aluminum alloy plates. It showed that the fracturemechanism is ductile fracture through the analysis by SEM. It also found that the elementMg, Er were distributed dispersedly. It leads to form the second phase particle, whichhinder dislocation motion and improve alloy intensity.AC TIG welding is adopted, welding current is40A, argon flow is6L/min and thethickness of plate is1.5mm. The components of welding wire are two kinds of weldingfiller materials, they are Al-Mg wire and parent metal wire respectively. Analyzed themicrostructure and property of welding joints during four kinds of heat treatment process,it found that the best progress is：rolling+welding+T6treatment. The tensile strength is300MPa and the strength factor of welded seam is0.76. The fracture mechanism is mixed fracture and the heat affected zone is the tensile fracture area. Meanwhile the elongation islow.