Cold metal transition brazing method for thin galvanized steel sheet

Abstract

According to the thin galvanized steel sheet cold metal transition brazing method, the welding spot position, the welding wire dry elongation, the welding time, the protective gas flow, the welding current, the arc length correction value and the thrust correction value are adaptively set according to different sheet thicknesses, and a cold metal transition welding process is adopted for welding. After welding is completed, the inner plate and the outer plate which are connected through a plurality of welding spots have enough connection strength, and the problems of dislocation and the like of the inner plate and the outer plate in the carrying process are solved. The welding heat input of the process is small, and the thermal deformation of the welded steel plate is small. In the welding process, molten metal liquid droplets are spread towards the periphery under the impact of high-flow protective gas and are rapidly solidified, and finally, the surplus height of a formed welding seam is low.

Description

technical field [0001] The application belongs to the field of metal material processing, and in particular relates to a method for cold metal transition brazing of thin galvanized steel sheets. Background technique [0002] Galvanized steel has good corrosion resistance, and parts such as front and rear covers of automobiles are often made of galvanized steel. The production process of automobile front and rear covers generally includes four steps: gluing, pressing, piping and drying. Among them, after the hemming process is completed, the product needs to be transported to the drying workshop for drying. Since the inner and outer panels of the front and rear covers of the car are bonded by sealant and mechanism glue, the colloid cannot be produced in a relatively short period of time. Sufficient connection strength, and the mass of the inner and outer panels is relatively large, therefore, during the handling process, the inner and outer panels of the front and rear cover...

AI Technical Summary

Problems solved by technology

However, for the laser welding process, on the one hand, due to the high heat input of the laser beam, the temperature gradient of the welded joint is relatively large, which makes the residual stress in the welded joint large and the strength of the weld is insufficient; on the other hand On the one hand, too high heat input will also cause large thermal deformation of the welded steel plate

For the resistance spot welding process, there is a process of extruding the plate during the spot welding process, which will cause excessive deformation of the extruded part of the welded workpiece

[0003] The above two welding processes will lead to large deformation of the outer panels of the front and rear covers of the car, and the flatness of the outer panels cannot meet the requirements of the next spraying process

In the later stage, the outer panel needs to be polished and repaired, which will seriously affect the production efficiency and increase the production cost

In addition, the boiling point of zinc is only 960°C. The excessive heat input of the above two welding processes will cause a large amount of gasification and volatilization of the galvanized layer on the surface of the plate, which will deteriorate the working environment and seriously damage the health of the operators in the workshop.

Images