Method for overlaying welding of duplex stainless steel

Abstract

A method for the overlaying welding of a duplex stainless steel comprises the following steps: A, integral preheating: the preheating temperature is 250-300 DEG C, and thermal insulation is carried out for 0.8-1.2 hours; B, overlaying welding implementation: the welding current is 180-220A, the welding voltage is 25-29V, the welding velocity is 350-450mm / min, and the interlayer temperature is 250-300 DEG C; C, annealing heat treatment: the initial temperature is 200-300 DEG C and is gradually increased to 700-750 DEG C, and thermal insulation is carried out for 1.8-2.5 hours; and D, a workpiece is cooled in a furnace to below 150 DEG C and then is discharged to be naturally cooled to the room temperature in the air. According to the method for the overlaying welding of the duplex stainless steel, the parameters of the welding temperature, heat treatment temperature after the welding and the like are reasonably selected, cracks due to hot and cold are obviously reduced, the toughness and the machinability of the duplex stainless steel are increased, and when the method is used for the overlaying welding of the duplex stainless steel of a ship lift guide wheel, all the performance indexes can satisfy the requirements.

Description

technical field [0001] The invention relates to a duplex stainless steel surfacing welding method, in particular to a duplex stainless steel surfacing welding method for guiding wheels of a ship lift, and belongs to the field of welding technology. Background technique [0002] Duplex stainless steel is an alloy material based on ferrite and austenite. In its metal microstructure, the proportion of ferrite and austenite each accounts for 50%, so it is called duplex stainless steel. Compared with ordinary stainless steel, duplex stainless steel has high strength, good toughness, excellent comprehensive mechanics, and strong corrosion resistance, especially in the harsh medium environment (such as high Cl- content), the resistance of duplex stainless steel Pitting corrosion, crevice corrosion resistance, stress corrosion resistance and corrosion fatigue resistance are significantly better than ordinary stainless steel. Therefore, in the fields of petroleum, chemical industry a...

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Problems solved by technology

[0005] The present invention aims at the process defects such as cold cracks, hot cracks, pores and welding slag that are easy to occur in the surfacing layer existing in the gas shielded welding of the existing duplex stainless steel flux-cored welding wire, and the surfacing layer has too high hardness, high brittleness and poor machinability and other defects and deficiencies, provide a duplex stainless steel surfacing welding method, through the reasonable selection of welding parameters such as welding preheating temperature and interlayer temperature, post-weld heat treatment temperature, heat treatment time, etc., significantly reduce cold cracks, hot cracks, porosity and welding slag and other process defects, as well as reducing the hardness of the surfacing layer, improving its toughness and machinability, the duplex stainless steel surfacing welding used for the guide wheel of the ship lift, and its performance indicators fully meet the requirements of the guide wheel