Low-temperature cold shield thin-wall aluminum alloy guide pipe structure and vacuum brazing process and application thereof

Abstract

The invention relates to the technical field of vacuum brazing and low-temperature cold screens, and provides a low-temperature cold screen thin-wall aluminum alloy guide pipe structure and a vacuum brazing process and application thereof. According to the vacuum brazing process provided by the invention, the assembly tool is arranged, so that the thin-wall aluminum alloy pipe and the semicircular sleeve can be fixed, supported and pressed and keep a correct position relationship, and the thin-wall aluminum alloy pipe and the semicircular sleeve form firm metallurgical bonding through vacuum brazing; the vacuum brazing efficiency is very high, stress and deformation caused by uniform brazing heating are small, and the precision of the size of a weldment is guaranteed. According to the low-temperature cold shield thin-wall aluminum alloy guide pipe structure, the semicircular sleeve is welded to the low-temperature cold shield, and the phenomenon of cold leakage of the low-temperature cold shield caused by cracks and weld penetration of the guide pipe due to welding does not need to be worried about. The brazing quality is stable, the production efficiency is high, the structure is light, the space utilization rate is high, the heat conductivity coefficient is large, heat resistance is small, and low-temperature cold shield can be rapidly achieved.

Description

technical field [0001] The invention relates to the technical field of vacuum brazing and low temperature cold shield, in particular to a low temperature cold shield thin-walled aluminum alloy conduit structure and its vacuum brazing process and application. Background technique [0002] The interlayer of the high-vacuum insulated storage container is provided with a low-temperature cold shield, and the low-temperature medium flows in the thin-walled aluminum alloy tube to conduct the cold energy to the aluminum alloy cylinder wall, so that it can quickly realize the low-temperature cold shield and reduce the liquid caused by the thermal radiation of the internal storage container. Evaporation losses of nitrogen, liquid helium, etc. Usually low temperature cold screen has the following structure: [0003] The aluminum alloy tube structure is welded on the low temperature cold screen wall. Due to the thin wall of the aluminum alloy tube, it is easy to cause cracks or burn-th...

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Problems solved by technology

[0003] The aluminum alloy tube structure is welded on the wall of the low-temperature cold screen. Due to the thin wall of the aluminum alloy tube, it is easy to cause cracks or burn-through of the aluminum alloy tube during welding, which makes the manufacturing process extremely difficult, and there is a possibility that the low-temperature cold screen will freeze during later use. risk of leakage

[0004] The aluminum alloy tube is tightly attached to the low-temperature cold screen wall through the hoop structure. The hoop above the aluminum tube will absorb part of the cold energy. The contact surface between the aluminum tube and the tube wall is very narrow and the full length of the aluminum tube cannot be guaranteed. They are all in contact with the wall of the cylinder, so it is impossible to achieve the fastest and most efficient low-temperature cold shield

[0005] The aluminum alloy tube structure with "legs" is welded on the wall of the low-temperature cold screen. This kind of aluminum tube with "legs" needs to be specially customized. The customization cost is high and the cycle is long. If the customized aluminum tube is to ensure that the welding does not damage the aluminum For the tube body, there will be a narrow or long distance between the aluminum tube and the "legs", and the welding of the "legs" on both sides of the aluminum tube cannot achieve full penetration, so the "legs" of the aluminum tube and the There is a long gap in the radial direction between the cylinder walls, and the customized aluminum tube still has some deficiencies in cooling speed and efficiency

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