Ultrasonic treatment of the solidifying metal is a promising method for improving the quality of fusion welding. A method to combine the ultrasonic waves to the welding process using arc excited ultrasonic emissio...Ultrasonic treatment of the solidifying metal is a promising method for improving the quality of fusion welding. A method to combine the ultrasonic waves to the welding process using arc excited ultrasonic emission, called arc ultrasonic, was high frequency modulation of the arc plasma. The effects of arc ultrasonic on the weld including the fusion zone, the partially melted zone and the heat affected zone are described. The arc ultrasonic energy changes the weld microstructure. In the fusion zone, the primary dendrite arm spacing decreases significantly and more acicular ferrite appears. In the partially melted zone, a large amount of fine grains appear. In the heat affected zone, the width of the tempered zone increases with increasing modulation frequency and the microstructure is refined. The results show that arc ultrasonic is a new and effective way for improving weld quality. 展开更多
The influence of heating cycles during plasma metal inert gas (MIG) welding on the microstructure and corrosion properties of the AA5754 automotive alloy has been investigated. The high heat input during plasma-MIG we...The influence of heating cycles during plasma metal inert gas (MIG) welding on the microstructure and corrosion properties of the AA5754 automotive alloy has been investigated. The high heat input during plasma-MIG welding results in a significant modification in the microstructure of the AA5754 alloy adjacent to the fusion boundaries. As a consequence of partial melting of the Al-Fe-Mn-(Si) intermetallics at the partially melted zone (PMZ) and segregation of the high melting point elements (particularly Fe and Mn) toward the fusion zone, severe galvanic corrosion attacks can be enhanced along the PMZ of the AA5754 weld during exposure to aqueous corrosion environments.展开更多
基金Supported by the National Natural Science Foundation of China ( No.5 9775 0 61)
文摘Ultrasonic treatment of the solidifying metal is a promising method for improving the quality of fusion welding. A method to combine the ultrasonic waves to the welding process using arc excited ultrasonic emission, called arc ultrasonic, was high frequency modulation of the arc plasma. The effects of arc ultrasonic on the weld including the fusion zone, the partially melted zone and the heat affected zone are described. The arc ultrasonic energy changes the weld microstructure. In the fusion zone, the primary dendrite arm spacing decreases significantly and more acicular ferrite appears. In the partially melted zone, a large amount of fine grains appear. In the heat affected zone, the width of the tempered zone increases with increasing modulation frequency and the microstructure is refined. The results show that arc ultrasonic is a new and effective way for improving weld quality.
文摘The influence of heating cycles during plasma metal inert gas (MIG) welding on the microstructure and corrosion properties of the AA5754 automotive alloy has been investigated. The high heat input during plasma-MIG welding results in a significant modification in the microstructure of the AA5754 alloy adjacent to the fusion boundaries. As a consequence of partial melting of the Al-Fe-Mn-(Si) intermetallics at the partially melted zone (PMZ) and segregation of the high melting point elements (particularly Fe and Mn) toward the fusion zone, severe galvanic corrosion attacks can be enhanced along the PMZ of the AA5754 weld during exposure to aqueous corrosion environments.
