Research On Welding Reinforement Of 2219 Aluminum Alloy

The 2219-87 aluminum alloy has been wide used in the tank of the carrier rocket,due to the excellent weldability and crack resistance.Through the mechanical properties of 2219-87 aluminum alloy TIG welded joint analysis,the fracture of aluminum alloy welded joints usually occured in the vicinity of the heat-affected zone and fusion line.The mechanical properties decline of HAZ and fusion line mainly resulted by thermal influence of the welding process.In addition,the shape of the characteristics of the weld,stress concentration and residual stress after welding will also lower the joint strength.Therefore,the fracture usually occurred in there,and which become the weak areas of the 2219-T87 welded joints.CMT welding experiment was conducted on the 6 mm thick 2219-T87 aluminum alloy plates,and the welding process of the weak area of the joint was studied.The results showed that the welding current,the deposition speed and EP / EN all affect the forming of the weld.When welding current 160 A,welding speed 160 cm/min,EN/EP =10/4,air flow 15 L/min,the weld shape was good.Different welding processes have little effect on the microstructure of the original joints.Through the welding reinforcement process,the tensile strength and yield strength of joints were obviously improved.When the AC CMT was used in the normal reinforcement welding,there was no obvious defect The yield strength of the joint is improved by 29.6%,the tensile strength was increased by 40.3% and the elongation rate of the joint was improved by 31%.