Welding technology of spiral steel pipe

Spiral steel pipe welds such as the gap is too large, the composition of the vicinity of the effect of reduction, the lack of eddy current heat, weld intergranular junction failure occurs or not cracking; such as the gap is too small to form a nearby effect increases, welding heat is too large, constitute welding And the weld is kneaded and rolled to form a deep pit, which affects the surface quality of the weld. After the two margins of the tube are heated to the welding temperature, after the kneading of the kneading roll, the metal crystal grain mutual penetration, crystallization, the end of the formation of a solid weld. Spiral steel pipe if the kneading force is too small, constitute a small number of crystals together, the weld metal strength decreases, after the force will crack; if kneading force is too large , will make the molten state of the metal is squeezed out of the weld, not only reduces the weld strength, and will occur a lot of surface glitches, and even constitute a shortcomings such as welding joints.