Lucifer Furnaces delivered a large dual-chamber unit – a hardening furnace over a tempering oven – to a metal stamping manufacturer in the Midwest. The upper hardening chamber heats to 2300°F with 6.5 inches of multilayer insulation throughout the chamber. Heat is supplied through heavy-gauge, coil-wound wire elements in holders on the sides, back and door of the furnace. The lower-chamber tempering oven heats to a uniform 1200°F with a rear-mounted fan circulating air past the side-mounted heating elements.
A heavy-duty ceramic hearth plate protects the floor elements and insulation, and a 16-gauge stainless steel liner forms the work chamber. Both chambers are controlled with digital time-proportioning temperature controllers with timers and alarms. Safety features on this unit include high-limit controllers on each chamber that provide automatic shutdown in the event of a high-temperature excursion.