Common Defects of ERW Steel Pipe Welding

ERW steel pipe is fed into the molding machine, deformed into a cylindrical tube through an induction loop or contact welding angle, the magnetic field around the induction coil current is induced by the edge of the strip, the strip edge due to its resistance generated thermal resistance is heated, the heated extruded strip edge forming roll extrusion welds. High-frequency welding metal is not added, it is actually a forge welding. If production control is better, does not remain fused surface of molten metal or oxide. HAZ shaped like a drum, because the edges of the strip into the strip entering the high-frequency current to generate heat from the end and side portions of the strip edges. HAZ color slightly darker than the base metal because welding carbon steel strip edge heating to diffusion, cooling weld carbon is absorbed in the strip edges.

Common defects of erw steel pipe welding
High frequency pipe may be a variety of welding defects. Each defect has many different names, there is no recognized professional terminology. Name given below defective, another common name in brackets defects: ① inclusions (burnt black oxide); ② pre-arc (white burnt oxide); ③ lack of fusion (slotted); ④ edge lack of fusion (wavy edge); ⑤ central insufficient fusion (cold welding central); ⑥ stick welding (cold welding); ⑦ cast welding (welding brittle); ⑧ pores (pinholes); ⑨ skip welding. These defects are not all but the most common high-frequency welding defects.