Method for improving strength and flexibility of super strength steel laser-arc hybrid welded joint

Abstract

The invention discloses a method for improving strength and flexibility of a super strength steel laser-arc hybrid welded joint, belonging to the technical field of super strength steel welding. The welded joint in the conventional welding technology is low in strength and poor in flexibility. The method for improving strength and flexibility of super strength steel laser-arc hybrid welded joint provided by the invention is characterized by comprising the following steps of: firstly, fusing the to-be-connected surfaces of two to-be-welded work pieces in advance by adopting a preprocessing laser to form a laser fusion preprocessing region, wherein the preprocessing laser power is 2-3kW, the scanning speed v1 is 1.5-2.5m / min, and the scanning overlap rate is 25-35%; and then, butting the fused to-be-connected surfaces of the two to-be-welded work pieces, and welding the to-be-connected surfaces by laser-arc hybrid welding. The method provided by the invention is used for butting welding of high-thickness super strength steel plates, and can improve the strength of the welded joint and improve the flexibility of the welded joint.

Description

technical field [0001] The invention relates to a method for improving the strength and toughness of an ultra-high-strength steel laser-arc hybrid welding joint, which can improve the welding quality. For example, to improve the strength and toughness of an ultra-high-strength steel laser-arc hybrid welding joint, the end face of the weldment to be welded is firstly treated The laser melting pretreatment is carried out, the grain size in the laser melting pretreatment area is significantly reduced, and the grains are refined, and then the laser-arc composite heat source is used for welding, and the fusion line of the composite welding joint is located in the laser melting In the pretreatment area, the method belongs to the technical field of ultra-high strength steel welding. Background technique [0002] In the process of welding large-thickness ultra-high-strength steel plates using conventional MAG / MIG welding processes, due to the large heat input, the heat-affected zone...

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Problems solved by technology

[0002] In the process of welding large-thickness ultra-high-strength steel plates using conventional MAG / MIG welding processes, due to the large heat input, the heat-affected zone of the weld is large, and the grains in the heat-affected zone are coarse, so the strength and toughness of the welded joint decrease

In the process of welding large-thickness ultra-high-strength steel plates using laser-arc hybrid welding technology, the grains in the heat-affected zone of welding grow seriously; in addition, due to the addition of laser, the joints of the two workpieces to be welded are subjected to high temperatures locally, due to the heat along the The uneven distribution of the weld penetration direction leads to a very large difference in the structure and mechanical behavior of the formed welded joint and the base metal, which directly affects the fracture resistance behavior, capacity and service reliability of the welded joint. Directly related to the strength and toughness of welded joints

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