Ignoring original equipment manufacturers' (OEM) recommended maintenance schedules for induction heating equipment can create problems that are not apparent from just looking at the system. Following a regular maintenance schedule can minimize equipment-breakdown surprises. This article offers recommended maintenance procedures for heat-treat coils and bus work, heat treat fixtures, quenching apparatus, melting furnaces and leads, forging coils and water-cooled skid rails and air and hydraulic components. Recommended maintenance of water-cooling systems, cooling towers and power supplies and heat stations was presented in Part 1 of this article (IH, June 2001). This information is not intended to replace OEM equipment manuals, but it provides easy-to-use checklists for regular system maintenance.
Induction coils require periodic cleaning. Normal high-temperature water exiting coils can cause internal calcium scale build-up within the water-cooling paths. The scale, appearing as white, tan and green powder and sludge, functions as a thermal insulator, reducing thermal conduction and causing coils to fail prematurely at solder joints. The following schedule of preventive maintenance can minimize or eliminate this problem.