Laser welding method for tailored band steel

Abstract

The invention discloses a laser welding method for tailored band steel. The laser welding method is characterized by comprising steps of (1), shearing the tail of front band steel and the head of rear band steel and then aligning and splicing the front band steel and the rear band steel to form a spliced joint; (2), projecting two laser beams with adjustable distance and adjustable focal depths to positions near the spliced joint, enabling one laser beam to illuminate the front band steel and enabling the other laser beam to illuminate the rear band steel; filling the spliced joint with welding wires to weld the front band steel and the rear band steel. The laser welding method has the advantages that the welding joint is high in quality, and accordingly breakage of the cold-rolled band steel in continuous production procedures can be prevented.

Description

technical field [0001] The invention relates to a welding method, in particular to a strip steel tailor welding method. Background technique [0002] In the cold rolling continuous production process, it is very important to weld the end of the preceding hot-rolled strip to the head of the following strip to form a weld, and then make it pass through the rolling line to form continuous rolling, thereby improving production efficiency. At this time, if the quality of the weld is poor, the weld will break when passing through the rolling line, resulting in production interruption. [0003] Laser welding is suitable for many fields, especially the welding of steel strips, because of its high welding quality, no contact, large aspect ratio, small deformation, beautiful welding, and the mechanical properties of the weld are basically consistent with the base metal. However, for the cold tandem rolling mill, the material and thickness of the steel plates spliced ​​together by th...

AI Technical Summary

Problems solved by technology

However, if there is a large difference in the material and thickness of the steel plate, there will also be a large difference in the absorption efficiency of the laser beam energy by the steel plate. In this way, if the laser beam with the same power is used for welding, the heat sources on both sides of the weld will be asymmetrical. On the one hand, the welding seam is not melted uniformly, resulting in obvious appearance defects such as pores and undercuts during the welding process; on the other hand, the material deformation on both sides of the weld seam is inconsistent, resulting in large welding residual stress

In addition, there is a large difference in the material strength of the weld zone, heat-affected zone and base metal after welding, and it is easy to break the weld zone when the rolling mill dynamically changes specifications

At present, there are no good countermeasures for weld splicing on such materials and thicknesses. When the jump is too large, in order to avoid weld breakage, interspersed production is generally performed by inserting transition materials; The rolling machine will adopt empty pass-through belt to avoid the weld seam breaking when the material is processed. This operation method not only increases the difficulty of production organization and unnecessary contract surplus material, but also greatly reduces the production efficiency.

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