Spiral welded pipe into the steel unit, multi-channel roll rolling strip gradually rolled up, a gap is formed with an opening round tube, squeeze rollers reduction adjustment, the weld gap control at 1 ~ 3mm, and the weld ends flush.
1. If the gap is too large, resulting in reducing the proximity effect, eddy current lack of heat, weld crystal combined indirect adverse arising from lack of fusion or cracking.
2. The gap is too small, causing the proximity effect increases, excessive soldering heat, cause weld Burning; weld or extruded, rolled after the formation of the pit, affecting the quality of the weld surface.
After the two edges of the tube is heated to welding temperature in the extrusion of squeeze rollers form a common metal grain mutual penetration, crystallization, eventually forming a strong weld. If the SSAW steel pipe extrusion pressure is too small, the number of co-crystal formation is small, the weld metal strength is reduced by the force will produce cracking; if the pressing force is too large, will make the molten metal is extruded weld, not only reduces the weld strength, and will generate a lot of internal and external burrs, and even cause welding take sewing and other defects.
