A large-thickness thermoforming sheet metal material for automobiles and a spot welding method

Abstract

The invention provides a large-thickness thermoformed sheet metal material for automobiles and a spot welding welding method. By adopting the spot welding welding method of the invention, there is no need to modify the existing resistance spot welding production line, increase the thickness of the thin plate or add additional reinforcement plates, It can realize the resistance spot welding between the large-thickness thermoforming steel and the thin plate, and the realization method is to add silicon steel sheet as the intermediate medium between the thin plate and the large-thickness thermoforming material, and the silicon content of the silicon steel sheet is 2.4wt%-3.7wt% , with a thickness of 0.1‑0.2mm, adding two interface resistances to promote the generation and accumulation of heat on the side of the thin plate, so that it is easier to nugget and generate weld nuggets on the side of the thin plate. Further, through reasonable welding parameter settings, the thin plate can be effectively guaranteed Quality requirements for side welded joints.

Description

technical field [0001] The invention relates to the technical field of welding between large-thickness thermoformed steel for automobiles and thin plates such as mild steel, in particular to a large-thickness thermoformed sheet metal material for automobiles and a spot welding method. Background technique [0002] With the continuous increase in the lightweight and performance requirements of automobile structures, the application of thermoforming materials (tensile strength 1350-1500Mpa) is becoming more and more extensive. It is predicted that in the future, the application proportion of thermoforming materials in body-in-white will exceed 40%. At present, in the excellent body structure of ECB statistics, the proportion of thermoforming is about 12-30%. [0003] Large-thickness thermoforming materials (1.8mm-3.0mm) can be obtained through secondary rolling, but due to its large thickness, it cannot be welded with mild steel materials, and the tensile strength of mild stee...

AI Technical Summary

Problems solved by technology

However, this welding method has the following main disadvantages: laser welding requires the transformation of the factory's welding production line, which is expensive and takes a long time, and cannot be compatible with the current mass production line

The disadvantage of adopting this solution is that the laser soft area of ​​the part is expensive. Taking the B-pillar outer panel as an example, the part cost will increase by about 50 RMB; at the same time, due to the increase in the thickness of the thin plate side parts, the weight will also increase by about 14%.

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