Process for repair-welding steel casting through flux-cored wire CO2 gas shielded welding

Abstract

The invention relates to the cast steel industry, particularly to a process for repair-welding a steel casting through flux-cored wire CO2 gas shielded welding. During the application, the process for repair-welding steel casting products is characterized by selecting a flux-cored wire matched with a casting base material, determining welding process parameters reasonably, selecting a welding current of 150-300 A, a welding voltage of 23-40 V, a wire extension length of 15-25mm, a welding speed of 45-90 mm / s, a gas flow of 20-25 L / min, and performing WPQ (welding procedure qualification ) according to the IX volume of ASME (American Society of Mechanical Engineers). The process for repair-welding the steel casting through the flux-cored wire CO2 gas shielded welding solves the problem of low efficiency, high labor intensity, multiple joints and slag removal difficulty of manual SMAW (shielded metal arc welding), eliminates defects such as microcracks, porosity and slag inclusion of a repair-welding area, when compared with the SMAW, can improve the working efficiency to 3-5 times, reduces production costs to more than 50%, enables the hydrogen content of weld metal to be lower than 2.0 ppm and corrosion resistance to be strong, guarantees that physical and chemical properties accord with and exceed requirements of corresponding cast steel material standards, and is applicable to high-grade, precise and top-notch steel castings and steel castings of high pressure hydrogen valves.

Description

technical field

[0001] The invention relates to the steel casting industry, and relates to the flux-cored welding wire CO 2 Gas-shielded welding is a process for repairing defects in steel castings. Using this process to repair steel castings, it solves the problems of low efficiency of manual electrode arc welding, many joints, difficult slag removal, high labor intensity for welders, and high cost. Defects such as micro-cracks, pores, and slag inclusions are prone to appear on the repaired area. It can improve the work efficiency by 3-5 times, reduce the production cost by more than 50%, the hydrogen content in the weld metal is lower than 2.0ppm, and has strong corrosion resistance. It is suitable for high-precision, cutting-edge steel castings and high-pressure hydrogen-facing valve steel castings. It improves the quality of welding repairs, enhances the performance of high temperature resistance, high pressure resistance, corrosion resistance, and hydrogen corrosion resi...

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