Laser welding method for sealing hollow thin case aluminum alloy piston body

Abstract

A laser welding method used to seal the aluminum alloy plug in hollow thin case presses one aluminum alloy piston cover on a hollow cylinder aluminum case with one open end, to be heated and baked in a vacuum room, and vacuums to discharge the air in the case, takes out to be arranged into air, and processes laser welding on the combination between the cover and the case in passive pressure, to seal the hollow plug. The invention has the function of vacuum welding and fusion welding in air, to improve producing efficiency.

Description

technical field [0001] The invention relates to a laser welding method, in particular to a laser welding method for the sealing of a hollow thin-shell aluminum alloy piston body of an automobile air conditioner. Background technique [0002] The aluminum alloy piston is a key component in the automotive air-conditioning compressor, which reduces the moment of inertia by adopting a hollow structure. The compressor has the characteristics of low noise, low energy consumption, high speed and good control performance, thereby quickly occupying the automobile market. [0003] The hollow aluminum alloy piston is composed of an aluminum alloy cover and a hollow cylindrical shell with an open end welded, see figure 1 , It is required that the strength of the weld is firm and the weld has no pores. Electron beam welding or laser welding is generally used. [0004] Since the surface of the aluminum alloy has a reflectivity of more than 97% for infrared lasers and the high thermal c...

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Problems solved by technology

[0004] Since the surface of the aluminum alloy has a reflectivity of more than 97% for infrared lasers and the high thermal conductivity of aluminum itself, it is very difficult to weld aluminum. In addition, during the process of laser welding the piston, the heating at the weld seam makes the The pressure of the gas inside the piston rises rapidly, causing the air pressure in the piston to be greater than the atmospheric pressure when the weld is connected around the seam, and the gas rushes out, forming a small hole, causing the piston to be scrapped

In this regard, there are also secondary laser welding. For the first time, a low-power laser is used to seal the weld, and after cooling, a high-power laser is used for deep penetration welding. This method can improve the yield, but the secondary laser welding The efficiency is low, the cost is high, and there is a phenomenon of overburning of aluminum, and the tensile strength is greatly weakened

Vacuum laser beam welding requires the workpiece to be placed in a vacuum chamber, and then the laser beam is introduced into the workpiece placed in the vacuum chamber. There must be a pumping and deflation process during welding, the speed is too slow, and the work efficiency is too low.

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