Dissimilar metal welding method for low-carbon steel and cast iron

Abstract

The invention discloses a dissimilar metal welding method for low-carbon steel and cast iron. The welding method comprises the following steps that S1, base materials are prepared, wherein the carbon content of the low-carbon steel is less than or equal to 0.6wt%, the carbon content of the cast iron is 2-4wt%, and the thickness of the low-carbon steel and the thickness of the cast iron are smaller than or equal to 10 mm; S2, surface cleaning and assembling of the base materials are carried out, wherein the base materials are cleaned so as to remove oxides and oil stains on the surface, horizontal butt joint assembly is carried out on the to-be-welded low-carbon steel and cast iron which are subjected to the surface cleaning, and a tool clamp is adopted for fixation to form a to-be-welded part, wherein the assembling clearance of the butt joint between the low-carbon steel and the cast iron is less than 20% of the thickness of the low-carbon steel and the cast iron; and S3, a welding process is carried out, wherein the dissimilar metal connection of the low-carbon steel and the cast iron adopts a swing and offset self-melting welding process to weld the to-be-welded part, the deviation of a laser incidence point to deviate towards the low-carbon steel side is the 35-45% of swing amplitude, so that the crack resistance of a weld joint is improved. According to the welding method, the welding cost can be reduced, and the crack resistance of the weld joint can be improved.

Description

technical field [0001] The invention relates to a connection technology of dissimilar materials, in particular to a method for welding dissimilar metals of low carbon steel and cast iron. Background technique [0002] Welding of mild steel and cast iron dissimilar metals often occurs in product structures such as automobiles and air-conditioning compressors. Since the carbon and impurity content in cast iron is generally high, it is very unfavorable for welding. When welding with low carbon steel dissimilar metals, welding cracks are easily generated. In order to avoid cracks in the weld seam, the welding method of filling low-carbon steel welding wire is mostly used at present, such as the connection between the low-carbon steel shell of the compressor and the cast iron pump body inside the shell, using MAG welding; in addition, for more important structures, also Austenitic welding consumables with better crack resistance are required. Due to the need to fill the welding...

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Problems solved by technology

[0004] However, if welding wire is added during the laser welding process, the input of welding energy needs to be increased, which is unfavorable for controlling welding deformation, and the welding cost increases accordingly. Compared with conventional welding methods, there is no obvious advantage

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