Vacuum Brazing and Performance Evaluation of T2 Copper Block and 316L Stainless Steel Tube

The International Thermonuclear Experiment Reactor (ITER) Thermal shield (TS) serves as a cryogenic heat exchanger to maintain the thermal stability of ITER superconducting magnet coil, which is critical control plasma during operation device. TS composed long-length 316L stainless steel (SS) and copper brazed joints. In this case, feasible fabrication design for CCS presented, accomplished by three kinds joining processes (vacuum brazing, friction stir weld, TIG weld). reliable design, brazing quality as-brazed long-distance SS joints plays role in conductivity performance shield. Therefore, high-quality vacuum process SS/Cu applied low-temperature superconductor system was first studied. macro metallography analysis demonstrates braze ratio samples 100%, no crack or defect observed samples. microstructural characterization reveals seams are silver-based Ag-rich eutectic. micro-shear test indicates that shear strength tube joint 205 MPa, with fracture position located on side; zone will be most vulnerable addition, SEM results illustrated morphology displayed ductile feature. demonstrated highly precise depth drilling employed paper ensured good clearance, resulting 100% it can concluded SS/Cu-brazing