Influence of Manufacturer and Orientation on Weld Behavior of AgC

Silver-graphite is a standard choice for low voltage switchgear when minimal welding forces are required. Today, contacts from AgC are available on the market from several manufacturers, typically as extruded material in parallel and perpendicular orientation as well as conventional press-sinter-repress parts. In this work, AgC5 sourced from three manufacturers, in different orientation and production technologies is compared in make tests against AgWC performed with 1400 A for 250 operations. Weld force distributions are analyzed and statistically compared. Welding force and frequency for AgC5 shows variation between manufacturers with two manufacturers resulting in similar weld force distributions while a third one shows higher weld forces but reduced weld frequency. Manufacturer A shows higher variability between production lots while manufacturer B shows consistent weld forces. Comparing material in parallel and perpendicular orientation cut from the same extruded blank confirms ~3x lower welding forces and weld frequency for the parallel orientation. Press-sinter-repressed material shows lower weld force, but increased weld frequency compared to parallel orientation.