Welding method for air exhaust adapter and air exhaust pipe of miniature fission chamber

Abstract

The invention provides a welding method for an air exhaust adapter and an air exhaust pipe of a miniature fission chamber, aiming at solving the problems that the size of the air exhaust adapter and the air exhaust pipe of the miniature fission chamber is small, the welding end face is narrow, the test welding space is small, the wall of a to-be-welded part is thin, penetration welding and penetration welding are easy, obvious deformation is easy to occur after welding, and subsequent assembly and leak rate test cannot be ensured. The method comprises the following steps of testing the welding depth, determining welding parameters, assembling a to-be-welded part to ensure a gap of a to-be-welded end face, carrying out laser welding with the circumference not smaller than 360 degrees, and carrying out leak detection on a welding spot. By means of the welding method, it is guaranteed that over-welding, weld penetration and deformation do not occur to the air exhaust adapter and the air exhaust pipe under the miniature size, the problems that the welding assembly difficulty of the air exhaust adapter and the air exhaust pipe is large and the like are solved, it is guaranteed that the air leakage rate of welding spots meets the design requirement, the neutron fluence rate is accurately measured, and miniaturization and localization of the fission chamber are achieved.

Description

technical field [0001] The invention belongs to the field of micro-device welding, and in particular relates to a welding method for a miniature fission chamber exhaust adapter and an exhaust pipe. Background technique [0002] As one of the important components of the reactor core measurement system, the microfission chamber is mainly used to measure the neutron flux rate of the reactor core. Due to its harsh service conditions and strict parameter requirements, it is difficult to design and manufacture the micro-fission chamber, especially when it comes to the high requirements for the sealing of the end faces of the micro-components and the difficulty of assembly. Therefore, microfission chambers mainly rely on imports. Although there are domestic products, they are rarely used. [0003] In 2019, the China General Nuclear Power Research Institute and the Institute of Nuclear Physics and Chemistry of the China Academy of Engineering Physics jointly developed a miniature f...

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Problems solved by technology

However, the rubber seal assembly is not suitable for the high temperature environment of the reactor, and it is easy to cause seal failure

The welding and sealing assembly method also faces the following problems when assembling: First, the air extraction adapter is a stepped rotary part with a small size, the maximum outer diameter is 3.7mm, and the thickness is 2.0mm. The outer diameter of the welding assembly is required to be 2.7mm, the inner diameter is 1.2mm, its wall thickness is 0.75mm, and the axial dimension of this section is only 0.5mm, while the diameter of the exhaust pipe is 1.2mm, the inner diameter is 0.8mm, and its wall is only 0.2mm thick; The size of the weldment itself is small, and the welding space between the end face of the exhaust pipe to be welded and the end face of the adapter to be welded is only 1.2 mm. The ring seam with a diameter of less than 0.05 mm in width has limited welding space.

Secondly, the wall of the weldment is thin and easy to be welded through, or the adapter or the sealing end face is deformed due to over-welding, or the height of the solder joint is too high due to over-welding, the deformation of the adapter or the sealing end face and the height of the solder joint are too high due to over-welding. It cannot be guaranteed that the assembly of the subsequent leak detection tooling will affect the leak rate test or the leak rate test of the welded assembly is unqualified, and thus the subsequent assembly of the micro-fission chamber cannot be guaranteed

Finally, if the welding parameters are improper and the welding depth is insufficient, it will affect the connection strength and air leakage rate between the suction adapter and the welding end of the suction pipe

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