Method for preparing steel-aluminum dissimilar metal overlap joint by adopting CMT technology

Abstract

The invention provides a method for preparing a steel-aluminum dissimilar metal overlap joint by adopting the CMT technology. The method comprises the following steps: an aluminum alloy plate is placed on a galvanized steel plate in an overlap manner and fixed by utilizing a fixture, wherein the overlap amount ranges between 5 mm and 20 mm; and a CMT welding machine is utilized, a welding gun is inclined towards the aluminum alloy plate to form an angle of 1-45 degrees with the vertical direction, the welding gun is inclined towards the forward direction by 5-30 degrees, the perpendicular distance between the welding gun and the galvanized steel plate is 10-20 mm, and the welding speed is 0.4-1.0 m/min. According to the method provided by the invention, the CMT technology is improved based on an original MIG welding power source, thereby converting molten droplet transfer into cold metal transfer, and reducing the metal spatter when the heat input during a welding process is reduced; and accordingly, the method is very suitable for welding of the aluminum alloy plate and the galvanized steel plate.

Description

technical field [0001] The invention relates to the field of arc welding metals, in particular to a method for preparing lap joints of steel-aluminum dissimilar metals using CMT technology. Background technique [0002] In China, where energy shortage and environmental deterioration are becoming more and more serious, how to reduce the weight of transportation vehicles, increase their carrying capacity while reducing the consumption of fossil energy and reduce the impact on the environment has become the focus of the automobile industry and the aviation industry. Light metals represented by aluminum alloys have the advantages of high specific strength, good corrosion resistance, and low density, and can partially replace steel to prepare structural components. However, the service conditions are relatively harsh, and parts that need to bear heavy and variable dynamic loads, and need to work under high or low temperature conditions still need to be made of steel to ensure the...

AI Technical Summary

Problems solved by technology

[0004] The mechanical properties of the joint obtained by friction welding are better, but the size and shape of the joint will be limited

Laser welding and arc welding have a wide range of applications, but the heat input of these two types of welding is large, which will cause a thick layer of brittle intermetallic compounds at the steel-aluminum interface, which will affect the mechanical properties of the joint

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