Spiral weld seam has the following several types:


1. Spiral strip end weld: steel head that spiral weld on steel or steel weld head and tail;
2. Two spiral butt weld: spiral cut is to link the two together to form an annular weld;
3. Spiral tack welding: that is applied before the final welding. For fixed butt weld edges.


Parametric analysis of welding seam
⑴ weld width refers to the junction of the weld surface and base metal called weld toe. The single-pass weld cross-section, the distance between the two is called the seam weld toe width. 


⑵ beyond the surface of the weld reinforcement refers to the connection at the height of the weld toe portion of the weld metal is called reinforcement. I make the cross-section of the weld seam of the high increase in carrying capacity is increased, and can increase the sensitivity of ray radiography, but it will make the weld toe stress concentration. Usually require more than a high not be less than the base material, increasing its thickness and increase the height of the mother material, but the maximum should not exceed 3mm. 


⑶ penetration cross-section of the welded joint, the base material is called the depth of penetration of the molten. Certain value to ensure that the combined penetration weld and base metal strength. When the filler metal material (rod or wire) is constant, the penetration depth determines the size of the weld chemistry extreme. Different welding methods require different penetration value, for example welding, surfacing layer in order to maintain the hardness and reduce the dilution of the base metal of the weld, in the premise of ensuring penetration should require a smaller depth of penetration.