Electric resistance welding pipe machine

The electric resistance welding pipe machine is 3 to 5 times more efficient than conventional TIG welding. Afterwards, the TIG welding bottom sealing MIG welding filling and covering process was changed due to defects such as root incomplete penetration and cratering. The improved welding process basically solved the problem of insufficient penetration of the root, but reduced the welding efficiency. Increased investment in equipment and complicates operating procedures. Recently, the hot pot TIG automatic pipe welding machine was introduced from abroad. The principle of hot wire TIG welding is to supply the filler wire from a separate constant voltage AC source before it is fed into the weld pool. The resistance is heated to a high temperature of 650-800 °C, which greatly accelerates the melting speed of the wire, and its deposition rate is close to the MTG welding deposition rate of the same diameter. 

In addition, the good back sealing characteristics of the TIG method ensure the melting quality of the backing bead. Therefore, the hot wire TIG welding is a preferred welding method for butt welding of small diameter wall thickness pipes. However, the feasibility of using pulsed MIG welding in the docking of small diameter wall thickness pipes should not be completely negated. Through a large number of tests, it has been found that in the thick-walled tube MIG welding butt joint, more than 90% of the root end penetration is located in the super-arc section, and the sag sag is caused by overheating of the molten metal of the molten pool during continuous multi-layer welding. If the power of the welding power arc is precisely controlled, the formation of the above defects can be completely eliminated. However, due to the original welding power supply of the imported MIG welding automatic pipe welding machine, the thyristor pulse power supply can not realize the arc power program control, such as switching to the most advanced digital control inverter pulse welding power supply or waveform control pulse welding power supply (computer software control). Small), the welding arc power can be easily controlled according to the welding process requirements to ensure the welding quality of the joint.