Mechanical properties of ITER coil CICC steel jackets production

ITER cable-in-conduit conductor (CICC) used in the superconducting magnet system consists of a cable made of Nb₃Sn or Nb-Ti strands inserted in a stainless steel tube (called jacket or conduit). Depending on the coil type, the jacket material is either made of a low carbon AISI 316LN (for toroidal field coil) and AISI 316L grade stainless steels (for poloidal field and correction coils) or a high Mn austenitic stainless steel developed for ITER called JK2LB (for the central solenoid coil). Mechanical properties of base material and weld joint need to be tested at room and/or cryogenic temperature under predefined mechanical deformation and heat treatment conditions. The amount of required steel requires a tight mechanical properties control to ensure homogeneity during production within the ITER defined requirements. This paper will compare test results such as the ultimate tensile strength (UTS), the yield strength (YS), and the elongation to failure (EL) measured by all ITER jacket supplier test laboratories both for seamless tubes and weld joints.