Welding process special for thick dissimilar material plate

Abstract

The invention discloses a welding process special for a thick dissimilar material plate. The welding process is characterized by comprising the following steps: a, cutting double-surface and one-side grooves in a welding material; b, grinding the cut grooves and parts within at least 30mm site around a welding area; c, performing spot welding at positions 30mm away from the top ends of two sides of a weld joint, and avoiding any defect in spot welding; d, preheating a base metal at a temperature of at least 150 DEG C; e, welding the weld joint at one side of a large groove, welding a surface covering layer by the method of welding from two sides to the middle, and then performing carbon gouging and back chipping for the other side; f, welding another weld joint at one side of a small groove by the same method as the large groove; g, thermally treating a welding part. The process is high in welding efficiency and small in welding-caused deformation; the weld joints have the characteristics of being high in strength, high in toughness, no defect, and no delayed crack.

Description

technical field [0001] The invention relates to a welding method, in particular to a welding method for super-thick-wall dissimilar materials. Background technique [0002] There are many processes involving thick plate welding in the prior art. For example, publication number CN101288919A discloses a welding method for 50-120mm thick plates and ultra-thick plates. The main methods include blanking, groove processing, component assembly, Debris cleaning, setting of arc ignition / quenching plate, preheating before welding, bottoming of welding seam, welding of filling layer, welding flaw detection, control of steel plate deformation, heat treatment of welding parts, etc. Arc welding, the preheating temperature is controlled at 80-120°C, the thickness of each layer of weld is controlled within 5.0mm, the temperature between layers is controlled at 80-200°C, the welding current is 600-800 amperes, and the arc voltage is 28-35 volts , the welding speed is 35-42cm / min. [0003] ...

AI Technical Summary

Problems solved by technology

[0005] Although many welding processes for thick plates have been disclosed in the prior art, the welding process for ultra-thick dissimilar materials of S355J2+QT material with a plate thickness of 145mm~580mm and ABS DH36 material with a plate thickness of 35mm~140mm is now available. It is not mentioned in the existing technology that for the welding of materials of this specification, if the welding process is improper, the following problems are likely to occur: 1. Root cracks; 2. Surface cracks; 3. Lamellar tearing in the joint area and the heat-affected zone 4. The welding stress is large, the weld structure is coarse, and the impact toughness is reduced; 5. The welding efficiency is low

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