Development of a welding procedure for high conductivity, copper-beryllium alloy C17510

The BPX (Burning Plasma Experiment) toroidal field coil conductor is fabricated from plates of C17510, a copper-beryllium alloy. A development program was initiated by Princeton Plasma Physics Laboratory (PPL) to establish welding techniques and investigate the benefits of post-weld heat treatment for this alloy. Several process options were investigated. Since both the plate material and weld filler contain beryllium, the establishment of health/safety procedures was prerequisite to the start of the development program. Significant progress in elevating the physical integrity of the welds was achieved by simultaneously optimizing the weld procedure and the heat-treatment processing. The initial program phase resulted in reproducible welds which exhibited 0.2% offset yield strengths in excess of 80 ksi. The welding techniques were developed on commercially available automated welding equipment and the heat-treatment procedures were established to be compatible with large welded assemblies. In-process quality assurance techniques were investigated