A narrow gap laser welding method for thick plates

Abstract

The invention discloses a laser welding method for a thick plate and narrow gap structure. The laser welding method specifically includes steps: adjusting the focal point of a laser to an initial position of narrow gap welding; placing a powder feeding pipe in front of the laser welding direction, keeping a certain distance between the powder feeding pipe and the welding initial position, placing a gas curtain protection cover above the welding initial position, and opening protecting gas; opening a powder feeding device and enabling the powder feeding device to spread powder at certain powder feeding speed, and simultaneously opening the laser so as to start welding, and keeping the laser welding position, the powder feeding position and the position of the gas curtain protection cover relatively unchanged in the horizontal direction; returning the laser welding position, the powder feeding position and the position of the gas curtain protection cover to the initial position after completing the single pass welding, enabling the laser to move up for a certain distance along the Z axis, starting next pass welding, and performing the welding layer by layer in sequence.

Description

technical field [0001] The invention relates to a laser welding method, in particular to a thick plate narrow-gap laser welding method, which belongs to the technical field of laser material processing. Background technique [0002] With the rapid development of heavy industry, thick plate welded structure has been more and more widely used in shipbuilding, marine engineering, nuclear power equipment, aerospace and other fields. Thick plate welding is an essential key process in the construction of various large-scale steel structure projects. Especially in the field of nuclear power equipment, thick plates are most widely used (the thickness is generally more than 20mm, and the structural size is large, and can only be connected and formed through segmental processing), and the thickness range is also the largest. For example, reactor pressure vessels are mostly welded with large-thickness stainless steel plates. Some containers have wall thicknesses up to 250mm. With the...

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Problems solved by technology

However, the small groove size will prevent the tip of the welding torch from entering the inside of the groove. In order to make the droplet transition smoothly at the bottom of the weld, the dry elongation of the welding wire has to be increased, and the arc is attracted by the side wall of the groove. , making the arc unstable and reducing the welding quality

For example, in the patent No. 201020637762.X, a process method of welding thick plates using a laser arc hybrid welding torch is proposed, but the welding torch angle of the technical solution disclosed in this patent cannot be adjusted arbitrarily, resulting in the welding torch not being able to achieve a narrow gap and deep slope mouth welding

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