Welding method of pure niobium cryogenic vacuum pressure vessel

Abstract

The invention discloses a vacuum electron beam welding method suitable for pure-niobium low-temperature vacuum thin-walled pressure containers. The method is characterized by adopting two-pass welding, low linear energy input control, and design of two joint structures. Compared with the prior art, the method has the advantages and beneficial effects that the erosion of harmful gases is avoided, the quality of welding joints is good, the x-ray test confirms that excessive air vents, failure of fusion, cracks and other defects do not exist, the regions of the welding joints have strong conductive capability, the member welding deformation amount is small, and the overall molding precision of the pressure container is high.

Description

technical field [0001] The invention relates to the technical field of processing, manufacturing and welding of pressure vessels, in particular to a welding method for a low-temperature vacuum thin-walled pressure vessel of pure niobium (Nb), a non-ferrous metal with low-temperature superconducting properties. That is, the vacuum electron beam welding method for the pure niobium vacuum pressure vessel shell used under the condition of low temperature superconducting technology. Background technique [0002] Due to its low-temperature superconducting properties, pure niobium material has become the key to low-temperature vacuum thin-walled pressure vessels necessary for the development of cutting-edge equipment such as "large high-energy linear accelerators", "synchrotron radiation accelerators" and "free electron lasers" in the field of international engineering physics Metal raw materials. As the heart part of the accelerator, the superconducting cavity is a typical repres...

AI Technical Summary

Problems solved by technology

At present, the industry mainly adopts the argon arc welding (TIG) method to realize the connection and forming of the main parts, external branch pipes and flanges of this type of pressure vessel. The control of technical points such as protection is not ideal; in addition, the existing technology fails to add methods such as positioning steps to control the forming accuracy of the structural form of the welded joint, which may easily lead to obvious out-of-tolerance parts of the welded joint of the pressure vessel after welding. out of shape

Therefore, it will have adverse effects on the mechanical properties of welded joints of pure niobium thin-walled pressure vessels, the electrical conductivity of products, and the overall structural forming accuracy.

Images