Laser welding method for metal sheets applied to ultra low temperature environment

Abstract

The invention discloses a laser welding method for metal sheets applied to an ultra low temperature environment. The method comprises the following steps of: integrally putting a metal sheet I and a metal sheet II in an inert gas environment, heating to the dynamic strain ageing temperatures of the metal sheet I and the metal sheet II, welding a filler wire in a seam zone by adopting fiber laser, putting the welded metal sheets in a liquid nitrogen environment, and emitting high-energy short pulse laser to carry out double-side laser impact on the metal sheets covered with an aluminum foil. The filler wire is welded for the metal sheets through laser at the dynamic strain ageing temperatures, so that the seam quality of a metal welding joint is greatly improved, and the seam zone is combined tightly with the metal sheets; and by laser impact strengthening treatment of the welding joint and the metal sheets in the same working environment at an ultra low temperature, ultra low temperature corrosion resistance and mechanical property of a metal welding member are remarkably improved.

Description

technical field [0001] The invention belongs to the field of laser processing, and in particular relates to a laser welding method for thin metal plates applied in an ultra-low temperature environment. Background technique [0002] Laser welding is a high-energy-density welding method that uses laser as an energy carrier. It focuses the laser into a very thin high-energy-density beam and irradiates it on the workpiece to melt the workpiece by heating and then cool it to obtain a weld. After the laser beam is focused, its power density can reach 106W / cm2, which is dozens or even hundreds of times higher than that of ordinary arc welding. Compared with traditional welding methods, laser welding has the characteristics of large depth-to-width ratio, small heat-affected zone, high weld joint strength, narrow weld seam, small welding deformation, no impact on surrounding tissues, easy automation and no X-ray generation. , These outstanding advantages make laser welding one of th...

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Problems solved by technology

However, these technologies are mainly dependent on imports, which has greatly restricted the development of the LNG industry and is also extremely detrimental to the country's energy security.

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