ERW pipe machine

Electric resistance welding is to press the workpiece to be clamped between two electrodes and apply an electric current, which is heated to a molten or plastic state by the resistance heating effect caused by the current flowing through the contact surface of the workpiece and the adjacent region, so as to form a metal. A combination of methods. Welded pipes made with resistance welding are called electric resistance welded pipes (erw pipe).

ERW pipe machine
ERW pipe machine, its efficiency is 3 to 5 times higher than the traditional TIG welding. Due to frequent occurrence of defects such as incomplete penetration of the root and sagging of arc pits, the TIG welding MIG welding filler and capping process was used. Although the improved welding process basically solved the problem of incomplete penetration of the root, the welding efficiency was reduced. Increased investment in equipment, but also complicated operating procedures.

The principle of hot wire TIG welding is to supply the filling wire with independent constant voltage AC power before it is fed into the welding bath. Resistance heating to a high temperature of 650~800°C, which greatly accelerates the melting speed of the wire, and its deposition rate is close to that of the MTG welding of the same diameter. In addition, the TIG method's good back-sealing feature ensures the quality of back-weld welds. Therefore, hot-wire TIG welding is a preferred welding method for butt welding of small-diameter wall thick tubes. However, the feasibility of using pulsed MIG welding in the jointing of small-diameter thick-walled tubes should not be completely rejected. A number of tests have been conducted to find out that in thick-walled pipe MIG welding butt joints, more than 90% of the root penetrations are located in the super-arc, and the sagging of the arc pit results from overheating of pool metal heat accumulation during continuous multilayer welding. If the precise control of the power of the welding power supply arc can be completely eliminated, the above defects can be eliminated. However, since the original welding power source of the imported MIG welding automatic pipe welding machine is a thyristor pulse power source, the program control of the arc power cannot be realized, such as switching to the most advanced all-digital full-digital control inverter pulse welding power supply or waveform control pulse welding power supply (computer software control. Small), the welding arc can be easily controlled according to the requirements of the welding process, to ensure the welding quality of the joint.

Read more: ERW Steel Pipe Manufacturing Process