High-speed laser welding method for invar film

Abstract

The invention discloses a high-speed laser welding method for invar film, and belongs to the technical field of high-speed laser welding. According to the high-speed laser welding method for the invar film, parallel laser beams of a laser welding machine are divided into first reflection laser beams and second reflection laser beams through a weir type spectroscope, the first reflection laser beams are focused through a focus lens to form a preheating laser beam, the second reflection laser beams are focused through a focus lens to form a welding laser beam, and the preheating laser beam and the welding laser beam carry out preheating and welding on a weld joint of a welding test piece at the same time. According to the high-speed laser welding method for the invar film, welding is carried out in a double-beam laser serial mode, the previous laser beam is used for preheating, the later laser beam is used for carrying out welding, the temperature gradient and welding stress are reduced through control over distribution of weld heat input energy on the weld joint and in the nearby area, and therefore high-speed flawless welding of invar is achieved.

Description

technical field [0001] The invention relates to a high-speed laser welding method for an invar steel film, belonging to the technical field of high-speed laser welding. Background technique [0002] Invar steel (Invar steel, also known as Invar steel, also known as Invar steel and Invar steel) is a FeNi36 alloy, and its coefficient of linear expansion at room temperature is lower than 1.6×10 -6 k -1 , about one-tenth of low carbon steel, and has little change in a large temperature range, so it is widely used in precision measurement devices, electronics industry and liquefied natural gas ships. However, invar steel has a single-phase austenitic structure and is highly sensitive to hot cracking. The welding hot crack problem seriously affects the welding quality and production efficiency. Invar steel is easy to form hot cracks and reheat cracks during welding, and there are strict requirements on the welding heat input and welding process, even when using tungsten argon ar...

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Problems solved by technology

Although the friction stir welding method can realize the welding of invar steel plates, it is difficult to connect the invar steel film with a thickness of only 0.7mm, and the problems such as welding deformation limit its application.

When laser welding invar steel is used, crack-free welded joints can be obtained, but the welding speed is low, and when the welding power is increased in order to increase the welding speed, the heat input of laser welding is highly concentrated (the depth-to-width ratio can reach up to 15: 1) Therefore, the temperature gradient between the weld seam and the surrounding metal material increases sharply, resulting in more prominent welding stress problems, and the formation of welding hot cracks, which seriously restricts the improvement of welding speed.

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