Development Of Sync-Welding-Controlling Magnetic 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, Sync-Magnetic-Controlling Device has directly effected on mechanics study and quality control in material processing. A new Sync-Magnetic-Controlling Device was developed with the dual inverter technique with the same frequency of the welding power of the voltage or current in this paper. The device can output AC and DC current and intermit alternative square wave pulse, which is matched with the welding voltage or current wave, 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 control circuit, driving circuit and feedback circuit of the developed device was improved and designed in the paper. The SG3525A chip and the CD74HC4046 chip were used respectively as PWM and SYNC control chip for dual inverter circuits. The corresponding driving circuit was designed. Compared with various power devices, power MOSFET were employed as the switches of the dual inverters. Soft-starting circuit is designed to overcome the surge current for protecting main switches. Test waveforms were measured when was installed and adjusted. The DC current is added to the new device compared to the old device, which only owns AC current. Every waveform was analyzed in the paper. The results of test show that the developed Sync-Magnetic-Controlling Device can output stable intermittent alternative square sync wave pulses and DC, which are matched to the welding voltage wave, its designed performance index can satisfy the designed request.Using the developed Sync-Magnetic-Controlling Device, intermittent alternative longitudinal magnetic field was applied in submerged arc bead welding. Comparing with the submerged arc bead welding without applying magnetic field, applying magnetic field and sync magnetic field, the result shows that applying intermittent alternative longitudinal magnetic field can refine effectively grain. The mechanism of electromagnetic stirring was analyzed by generalizing the results of test in this paper. Successful test shows the practicability of the developed Sync-Magnetic-Controlling Device.