Resistance spot welding（ RSW） is an efficient and convenient joining process for aluminum alloy sheet assembly. Because the RSW has the character of energy concentration and quick cooling rate, the microstructure tr...Resistance spot welding（ RSW） is an efficient and convenient joining process for aluminum alloy sheet assembly. Because the RSW has the character of energy concentration and quick cooling rate, the microstructure transformation of the base metal can be confined in the least limit. The material properties and the welding parameters have significant effects on the quality of the nugget. To predict the microstracture evolution in the melted zone and the heat-affected zone, an electrical, thermal, metallurgical and mechanical coupled finite element model is described and applied to simulate the welding process of the 6082 aluminum alloy. Experimental tests are also carried out. The comparison between experimental and numerical results shows that the adopted model is effective enough to well interpret and predict some important phenomena in ierms of the phase transformation in spot welding of 6082 aluminum alloy.展开更多
In order to analyze the maximum power density error with different heat flux distribution parameter values for double ellipsoidal heat source model, a general expression of double ellipsoidal heat source model was der...In order to analyze the maximum power density error with different heat flux distribution parameter values for double ellipsoidal heat source model, a general expression of double ellipsoidal heat source model was derived .front Goldak double ellipsoidal heat source model, and the error of maximum power density was analyzed under this foundation. The calculation error of thermal cycling parameters caused by the maximum power density error was compared quantitatively by numerical simulation. The results show that for guarantee the accuracy of welding numerical simulation, it is better to introduce an error correction coefficient into the Goldak double ellipsoidal heat source model expression. And, heat flux distribution parameter should get higher value for the higher power density welding methods.展开更多
基金This research was supported by National Natural Science Foundation of China （ No. 50575159 ） and project of Chinese Ministry of Education（ No. 106049, 20060056058）, Natural Science Foundation of Tianjin （06YFJMJC03400）.
文摘Resistance spot welding（ RSW） is an efficient and convenient joining process for aluminum alloy sheet assembly. Because the RSW has the character of energy concentration and quick cooling rate, the microstructure transformation of the base metal can be confined in the least limit. The material properties and the welding parameters have significant effects on the quality of the nugget. To predict the microstracture evolution in the melted zone and the heat-affected zone, an electrical, thermal, metallurgical and mechanical coupled finite element model is described and applied to simulate the welding process of the 6082 aluminum alloy. Experimental tests are also carried out. The comparison between experimental and numerical results shows that the adopted model is effective enough to well interpret and predict some important phenomena in ierms of the phase transformation in spot welding of 6082 aluminum alloy.
文摘In order to analyze the maximum power density error with different heat flux distribution parameter values for double ellipsoidal heat source model, a general expression of double ellipsoidal heat source model was derived .front Goldak double ellipsoidal heat source model, and the error of maximum power density was analyzed under this foundation. The calculation error of thermal cycling parameters caused by the maximum power density error was compared quantitatively by numerical simulation. The results show that for guarantee the accuracy of welding numerical simulation, it is better to introduce an error correction coefficient into the Goldak double ellipsoidal heat source model expression. And, heat flux distribution parameter should get higher value for the higher power density welding methods.
