Method for connecting aluminum alloy and steel by laser filler wire

Abstract

The invention relates to a method for connecting an aluminum alloy and steel by a laser filler wire, which is suitable for the field of dissimilar material connection and particularly suitable for the connection between dissimilar materials of which fusion points and thermal physical properties differ from each other greatly. The method comprises the following steps of: assembling a lap joint in which an aluminum plate is arranged on a steel plate, wherein a laser beam, a wire feeding nozzle and a protective gas nozzle are fixed in the same plane, the laser beam is vertically incident, and a laser focus, a wire dropping point of a welding wire and a protective gas feeding point are guaranteed to be consistent during welding; and melting the fed aluminum welding wire by using the laser to ensure that the molten aluminum welding wire is in fusion connection with the aluminum plate, simultaneously a micro fusion layer is formed on one side of the steel plate and then a fusion-braze welding connection is formed, thus the lap joint between dissimilar metals such as the aluminum alloy and the steel is realized. The method improves the connection efficiency between the dissimilar metals such as the aluminum alloy and the steel, and the tensile strength of the joint is over 149.6N / mm. The method solves the problems of long preparation time, low automation degree and poor reproducibility of welding results in the process of connecting pre-coated layers of the dissimilar materials such as welded-aluminum and the steel.

Description

technical field [0001] The invention relates to a laser welding method for connecting dissimilar metals of aluminum and steel through a filler wire, which is suitable for the field of dissimilar material connection, especially suitable for the connection of dissimilar materials with large differences in melting point and thermal physical properties. Background technique [0002] Energy is scarce in modern society, and energy-saving and emission-reducing products are increasingly favored by consumers. Many manufacturers have used lightweight materials or connected two materials in their products to achieve the goal of reducing the weight of the product itself. In worldwide industrial production, there are more and more "steel + aluminum" dissimilar metal welded structures. For example, in the automotive industry, the concept design of the new Audi TTASF body uses the manufacturing technology of mixing aluminum alloy and high-strength steel for the first time; BMW The 5 Serie...

AI Technical Summary

Problems solved by technology

In this method, filler wire is used as the connecting metal, a kilowatt-level laser is used as the heat source, and the heat conduction and melting process on the surface of the steel plate are controlled by strictly controlling the heat input during the welding process and the welding process. A mixed connection of welding and brazing is formed between the alloy and the steel plate, which not only realizes the connection between the aluminum alloy and the steel plate, but also controls the layer thickness of the intermetallic compound in the connection area, and improves the joint’s reliability through the formation of a small melting zone. The connection strength realizes the high-efficiency connection between aluminum alloy and steel, and solves the problem of high-quality and high-efficiency connection in the welding of dissimilar metals

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