Large-thickness thermal forming sheet metal material for automobile and spot welding method

Abstract

The invention provides a large-thickness thermal forming sheet metal material for an automobile and a spot welding method. By adopting the spot welding method, resistance spot welding of large-thickness thermal forming steel and thin slabs can be realized without reforming an existing resistance spot welding production line under the conditions that no existing resistance spot welding production line is needed, the thickness of the thin slabs does not need to be increased or extra addition of a reinforcing plate is not needed; a realization method is as follows: silicon steel sheets are addedbetween the thin slabs and the large-thickness thermal forming sheet metal material to serve as intermediate mediums; the content of the silicon steel sheets is 2.4 to 3.7 weight percent, and the thickness of the silicon steel sheets is 0.1 to 0.2 mm; two interface resistors are added to promote generation and accumulation of the heat of the thin slab side, so that the thin slab side is fused moreeasily and weld nuggets are produced on the thin slab side; and further, quality requirements of welded joints on the thin slab side can be effectively ensured by setting reasonable welding parameters.

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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