As a transmission medium, welding arc can be modulated to emit ultrasonic energy by exerting high-frequency electric current. The frequency of exciting electric current has notable influence on the signals recorded by...As a transmission medium, welding arc can be modulated to emit ultrasonic energy by exerting high-frequency electric current. The frequency of exciting electric current has notable influence on the signals recorded by the sensors and the metallographic structures of the welds. The resonance phenomenon of arc-uitrasonic has been found in the experiment. Both the resonance mechanism and the distribution of resonance frequency are discussed by the bui|t vibration equation.展开更多
TC4 alloy was welded by conventional TIG welding and arc-ultrasonic TIG welding respectively. The microstructure of joint was analyzed by means of optical-microscope, scanning electron microscope in order to study the...TC4 alloy was welded by conventional TIG welding and arc-ultrasonic TIG welding respectively. The microstructure of joint was analyzed by means of optical-microscope, scanning electron microscope in order to study the relationship between the macro-properties of joint and the microstructure. The results show that the joints were all welded successfully by conventional TIG welding and arc-ultrasonic TIG welding. With the increment of ultrasonic frequency and activated voltage, the width of joint became narrow step by step. The microstructure became more and more fine and was inclined to equiaxed crystal. Moreover, the dendrite depredation was not observed obviously. The properties of welded joint were improved markedly compared with that of conventional TIG welding.展开更多
To control the solidification process of metal, a new method, arc ultrasonic, was developed. A high frequency exciting supply was electromagnetically coupled with conventional welding supply. An arc excited ultrasonic...To control the solidification process of metal, a new method, arc ultrasonic, was developed. A high frequency exciting supply was electromagnetically coupled with conventional welding supply. An arc excited ultrasonic emission was induced successfully in arc combustion process. Some signals with different frequencies and currents were used in submerged arc welding and CO 2 gas shielded arc welding. The effects of arc ultrasonic on the structures and properties of the weld (including the fusion zone, coarse grain zone and heat affected zone) were studied. The results show that more acicular ferrites form in the fusion zone, the toughness is improved under the arc ultrasonic of different frequency, and the coarse microstructures in the partially melted zone is refined. [展开更多
基金the National Natural Science Foundation of China !(Grallt No.59775061).
文摘As a transmission medium, welding arc can be modulated to emit ultrasonic energy by exerting high-frequency electric current. The frequency of exciting electric current has notable influence on the signals recorded by the sensors and the metallographic structures of the welds. The resonance phenomenon of arc-uitrasonic has been found in the experiment. Both the resonance mechanism and the distribution of resonance frequency are discussed by the bui|t vibration equation.
文摘TC4 alloy was welded by conventional TIG welding and arc-ultrasonic TIG welding respectively. The microstructure of joint was analyzed by means of optical-microscope, scanning electron microscope in order to study the relationship between the macro-properties of joint and the microstructure. The results show that the joints were all welded successfully by conventional TIG welding and arc-ultrasonic TIG welding. With the increment of ultrasonic frequency and activated voltage, the width of joint became narrow step by step. The microstructure became more and more fine and was inclined to equiaxed crystal. Moreover, the dendrite depredation was not observed obviously. The properties of welded joint were improved markedly compared with that of conventional TIG welding.
基金Project(59775061)supported by the National Natural Science Foundation of China
文摘To control the solidification process of metal, a new method, arc ultrasonic, was developed. A high frequency exciting supply was electromagnetically coupled with conventional welding supply. An arc excited ultrasonic emission was induced successfully in arc combustion process. Some signals with different frequencies and currents were used in submerged arc welding and CO 2 gas shielded arc welding. The effects of arc ultrasonic on the structures and properties of the weld (including the fusion zone, coarse grain zone and heat affected zone) were studied. The results show that more acicular ferrites form in the fusion zone, the toughness is improved under the arc ultrasonic of different frequency, and the coarse microstructures in the partially melted zone is refined. [
