Weld treatment of spiral steel pipe

Spiral steel pipe will strip into welded pipe unit, the multichannel roll rolling, strip steel rolled up gradually, there is an open space form of round billet, adjust the quantity of the squeezing roller, make the weld gap control in 1 ~ 3 mm, and make joint flush on both ends.

1. If the clearance is too large, the adjacent effect will be reduced, the eddy current heat will be insufficient, and the weld crystal will not fuse or crack due to the bad indirect bonding.

2. If the clearance is too small, the adjacent effect will be increased, and the welding heat will be too large, resulting in the weld burn loss; Or a deep hole is formed after the weld is extruded or rolled, which affects the surface quality of the weld.

After the two edges of the billet are heated to the welding temperature, the common metal grains are formed under the extrusion of the extrusion roll to infiltrate and crystallize each other, and finally a solid weld is formed. If the extrusion pressure of spiral steel pipe is too small, the number of common crystals will be small, and the strength of weld metal will decrease, and cracking will occur after the stress is exerted. If the extrusion pressure is too large, the molten metal will be extruded out of the weld, which will not only reduce the weld strength, but also generate a large number of internal and external burrs, and even lead to weld joints and other defects.