The Development On Pipe All-position Ultra-narrow Welding Machine

If the advantage of ultra-narrow gap welding can be used for pipe welding,it will bring about rapid development for pipe welding technology at home and abroad. The ultra-narrow gap welding was carried out some research in our laboratory and some results have been achieved. The technology is hoped applied for pipe welding and a set of pipe all-position ultra-narrow welding machine for field welding is developed. Development arc welding generator and welding control system is focused on.To meet field pipeline welding requirements, DC arc welding generator by gas oline is developed.The arc welding generator uses third-harmonic excitation synchronous generator. By sampling welding current and welding voltage instantaneous waveform taken as feedback signal, an operational amplifier circuit produces pulse width signal to control IGBT which regulates excitation current of arc welding generator. This control method can improve responding speed of welding variables of arc welding generator to change of arc length. By regulating the feedback depth of welding voltage and welding current, arc welding generator can obtain dropping and constant voltage external characteristics. In the field large diameter pipe welding, dropping external characteristic can be used for root welding by shielded metal arc welding, and constant voltage external characteristic can be used for fill and cap welding by ultra-narrow gas metal arc welding with constant wire feed speed. Experiments show that the external characteristics of arc welding generator response rapidly and the welding parameters can be adjusted Continuously, adjustment range can meet the actual demand.To meet the requirements of pipe all position ultra-narrow welding for welding control system, welding control system is developed. The control system adopts SOC MCU as core and take segment control method.Pipe is divided into 24 channels and take different welding parameters for each channel. By welding control system, welding parameters is automatic adjustment. In addition, control system can achieve the control of buttons and display system of ultra-narrow gap welding machine. Control panel is simple, practical, functional,visual and intensity. The stability of control system is high and response speed is fast.