Continuous butt welding method using plasma and laser, and method for fabricating metal tube using the same

Abstract

A continuous butt welding method using plasma and laser, and a method for fabricating a metal tube using the butt welding method are disclosed. The butt welding method conducts a laser welding and a plasma welding together against an object to be welded, which has a very narrow butt space. In particular, the plasma is prior to the laser so that the object is preheated by the plasma, and then a preform is melted by a laser beam in order to accomplish the major welding. In addition, a metal sheet is bent to have a circular section so that its both ends are faced with each other, and then the faced both ends are welded using the aforementioned butt welding method, thereby fabricating a metal tube. The butt welding method and the metal tube fabricating method mentioned above remarkably improve a welding speed and productivity of metal tube.

Description

technical field [0001] The present invention relates to a butt welding method of metal materials and a method of manufacturing metal pipes using the method, and more particularly, to a method of improving welding speed by using two heat sources simultaneously, and manufacturing metal pipes using the welding method Methods. Background technique [0002] Laser welding and arc welding have been widely used to bring two metals against each other and weld them. [0003] The advantage of laser welding is that since laser welding can concentrate the heat source (for example, a laser beam) in a very small size, due to this small heat action area, laser welding can precisely weld small parts, which can be formed by forming keyholes. To guide seam welding (or deep penetration welding). However, the disadvantages of laser welding are that its narrow focal radius makes it difficult to track fine weld lines such as in butt welding, and multiple air holes can be generated in the welded ...

AI Technical Summary

Problems solved by technology

However, the disadvantages of laser welding are: its narrow focal radius makes it difficult to track fine welding lines such as in butt welding, and multiple air holes in the welded part due to unstable keyholes produced by laser welding

However, arc welding has a disadvantage in that arc welding is not suitable for welding delicate products with a narrow butt space (for example, 0.2 mm or less) because arc welding has a large-area heat source in the welded portion

For example, the combined laser welding-arc welding disclosed in the aforementioned Japanese and U.S. patent publications can be used to weld relatively thick plates, especially ordinary iron plates other than stainless steel, such as the bodies of ships or vehicles, but such Welding cannot be used to weld items with small butt space and small thickness

Images