The Effect of Plastic Deformation on Low Temperature Mechanical and Magnetic Properties of Austenite 316LN Tube for ITER TF Conductor

Abstract

While the manufacturing of superconducting CICC (cable in conduit conductor) and winding conductors into winding packs for ITER TF magnets, cold work is unavoidably applied on the jacketing tube. This article investigates the effect of plastic deformation on low temperature mechanical and magnetic properties of austenite 316LN stainless steel tube for ITER TF conductor. To simulate the manufacturing process of TF magnet, tubes were compacted, extended to 2.5% in longitudinal direction and heat treated. After each step, specimens were sectioned using wire cutting EDM, and tensile tests at 4 K, magnetic susceptibility measurements, and hardness tests have been carried out on those specimens. Remarkable reductions of elongation at failure have been observed as the amount of cold work is increased through compaction and extension. Further, correlations among results of tensile tests, magnetic susceptibility measurements and hardness tests are presented.