A welding process method for dissimilar metal parts

Abstract

The invention relates to the field of welding technology, in particular to a welding process method for dissimilar metal parts. It is used for welding between stainless steel workpieces and aluminum alloy workpieces or between low carbon steel workpieces and aluminum alloy workpieces, including the following steps: use the first welding wire to overlay the transition layer in the base metal welding area of ​​the stainless steel base, and the arc is deflected to the welding wire during welding; The second welding wire is used to melt and weld between the surfacing transition layer and the aluminum alloy base material, and the arc is biased towards the aluminum alloy layer during welding; after welding, the weldment is placed in a heat preservation furnace for heat preservation, and is cooled with the furnace after heat preservation for a preset time. Using the welding process method for dissimilar metal parts provided in the present invention, because the transition layer is first welded in the base metal welding zone of the stainless steel base layer in the welding process, and then the transition layer is welded with the aluminum alloy base material, the transition layer and the aluminum alloy base material can be welded. The melting point of the aluminum alloy base material is kept within the same range to ensure uniform composition of the weld after welding and no serious deformation of the weld.

Description

Technical field [0001] The present invention relates to the field of welding technology, in particular to a welding process method of an alien metal part. Background [0002] Since stainless steel and aluminum will form a variety of brittle intermetallic compounds such as solid solutions and eutectic crystals, the solid solution of steel in aluminum is 0.53% at a eutectic temperature of 650 °C, and the deposited metal of steel is almost insoluble in aluminum at room temperature. Therefore, a variety of intermetallic compounds and eutectic mixed structures appear in the weld during welding, which seriously affects the fusion and replacement performance between the two metals, making it extremely difficult for the weldability of steel and aluminum. The main problems in welding steel and aluminum: [0003] 1. The welded head is easy to oxidize. When steel is welded to an aluminum alloy, aluminum forms a refractory oxide (AL.) with oxygen in the air 2 O 3 This oxide is not only prese...

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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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