Effect of Fabrication Processes on SS316lN Jacket Material for Fusion Relevant Superconducting Magnet

The effects of various fabrication processes, such as compaction and swaging, during the fabrication of a cable-in-conduit conductor on the mechanical and metallurgical properties of jacket material (SS316LN) are discussed in this paper. Microstructure analysis of various samples is carried out, and the change in microstructures has been studied using scanning electron microscopy image analysis. The variation in hardness for the jacket material is also tested after swaging and compaction operations. The jacket samples are tested for their tensile strength, reduction in area, elongation, and impact strength as per applicable American Society for Testing and Materials standards. The ultimate tensile strength (UTS) is observed to be decreased for a sample compacted to 733 MPa when compared to virgin samples. On the contrary, the UTS increased significantly up to 1027 MPa in swaged samples. There is no linear relationship between tensile strength of SS316LN after cold working operations. The effect of thermal shock on the mechanical and metallurgical properties of the jacket material is also investigated.