Feasibility Study on Welding Structure of the HT-7Urn Toroidal Field Coil Case

摘要

The Toroidal Field (TF) coil case of the HT-7U superconducting tokamak device isrnmade of austenitic stainless steel 316LN and is designed to operate at cryogenic temperature (4rnK). 316LN can retain high strength and fracture toughness at 4 K. Feasibility study on technicalrnprocess of welding has been experimentally considered as a hopeful joint method for suppressionrnof post-welding deformation and reduction of over-heating. Meanwhile the final range of stress in-rntensity and the stress intensity factor (K) for pre-cracks of welding structure have been determinedrnby using J-integral. These related results are optimistic and have shown that there's no problemrnin strength and fracture toughness at the vicinity of the pre-crack tip. This paper introduces thernwelding structure of TF coil case in detail.