关键词: HL-2M 装置；Inconel625；高致密性焊接；316L；相对磁导率 

Abstract: Based on the development practice of HL-2M vacuum vessel, this paper introduces the high air 
tightness welding process of Inconel625, which can effectively reduce the occurrence of weld leakage and ensure 
that the ultimate vacuum of the vacuum vessel can reach 10⁻⁶Pa. In addition, the permeability control technology 
of 316L in the manufacturing process is introduced, so that the relative permeability of parts after processing is 
kept at μ< 1.04. 

Key words: HL-2M tokamak, Inconel625, Air tightness welding, 316L, Permeability