Welding process method of dissimilar metal part

Abstract

The invention relates to the technical field of welding, in particular to a welding process method for dissimilar metal parts. The method is used for welding a stainless steel workpiece and an aluminum alloy workpiece or welding a low-carbon steel workpiece and the aluminum alloy workpiece and comprises the following steps that a transition layer is surfaced in a base metal welding area of a stainless steel base layer through a first welding wire, and electric arcs deflect to the welding wire during welding; a second welding wire is used for fusion welding between the surfacing transition layer and the aluminum alloy base metal, and electric arcs deflect to an aluminum alloy layer during welding; and after welding is completed, a weldment is placed in a heat preservation furnace for heat preservation, and furnace cooling is conducted after heat preservation is conducted for preset time. According to the welding process method for the dissimilar metal parts, due to the fact that the transition layer is welded to the base metal welding area of the stainless steel base layer in the welding process and then welded to the aluminum alloy base metal through the transition layer, the melting point of the transition layer and the melting point of the aluminum alloy parent metal can be kept within the same range, the welding seam components are uniform after welding, and the welding seamcannot be seriously deformed.

Description

technical field [0001] The invention relates to the field of welding technology, in particular to a welding process method for dissimilar metal parts. Background technique [0002] Since stainless steel and aluminum will form various brittle intermetallic compounds such as solid solution and eutectic, at the eutectic temperature of 650°C, the solid solubility of steel in aluminum is 0.53%, and the deposited metal of steel is almost insoluble in aluminum. Therefore, a variety of intermetallic compounds and eutectic mixed structures will appear in the weld during welding, which seriously affects the fusion and replacement performance between the two metals, making the weldability of steel and aluminum extremely difficult. The main problems in welding steel and aluminum: [0003] 1. The welded joint is easy to oxidize. When steel and aluminum alloy are welded, aluminum and oxygen in the air form refractory oxides (AL 2 o 3 ), this oxide not only exists on the surface of th...

AI Technical Summary

Problems solved by technology

[0003] 1. The welded joint is easy to oxidize

When steel and aluminum alloy are welded, aluminum and oxygen in the air form refractory oxides (AL 2 o 3 ), this oxide not only exists on the surface of the molten pool, which affects the stability of the welding process, but also forms an oxide film that hinders the combination of liquid metal and reduces the mechanical properties of the weld

[0004] 2. Uneven weld composition

In addition, the density of the two metals (steel is 7930kg / m 3 , aluminum is 2700kg / m 3 ) is very different, when the steel is completely melted, the liquid aluminum floats above the liquid steel, and the composition of the weld is not uniform after cooling and crystallization

[0005] 3. Large welding deformation

[0006] 4. Welded joints are brittle and prone to cold cracks

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