Development And Application Of Dual Inverter Square Wave Welding Electromagnetic Stirring Device

Electromagnetic stirring welding technique has been developed as a new welding technology in recent years. Its application field is more and more extensive. As the key facility of electromagnetic stirring welding technique, the welding electromagnetic stirring device has direct effect on mechanics study and quality control in material processing. A new welding electromagnetic stirring device was developed with the dual inverter technique in this paper. The device can output intermittent alternative square wave pulse, and has many advantages such as small volume, simple circuit structure and high reliability. Its current amplitude, frequency duty cycle and alternative time can be adjusted continuously.The main circuit, control circuit and driving circuit of the developed device was studied and designed in the paper. The main circuit used the duai inverter structure. The SG3525A chip and the SG3526 chip were used respectively as PWM control chip for two inverter circuits. The corresponding driving circuit was designed. Compared with various power devices, power MOSFET were employed as the switches of two inverters. The parameters of the main circuit were designed and calculated. Soft -starting circuit is designed to overcome the surge current for protecting main switches. Test waveforms were measured when was installed and adjusted. Every waveform was analysed in the paper. The results of test show that the developed welding electromagnetic stirring device can output stable intermittent alternative square wave pulses, its every performance index can satisfy the design request.Using the developed welding electromagnetic stirring device, intermittent alternative longitudinal magnetic field was applied in aluminum 2219 M1G welding. Conparing with the aluminum weld applying and without applying magnetic field shows that applying intermittent alternative longitudinal magnetic field can refine effectively grain, increase the width and decrease the weld penetration. It can improve the crack resistance of the weld. The tension test shows that applying intermittent alternative longitudinal magnetic field can improve greatly mechanical property. The mechanism of electromagnetic stirring was analysed bygeneralizing the results of test in this paper. Success of electromagnetic stirring welding test shows the practicability of the developed electromagnetic stirring device.