L&L Special Furnace Co. Inc. delivered a highly uniform box furnace to a quality-control lab of a major U.S. steelmaker. The furnace, which has working dimensions of 11 inches wide x 10 inches high x 11 inches deep, is capable of heat treating a wide variety of tool steels (from D-2 to high-speed M-2) along with low-temperature tempering. It is equipped with a sealed case for inert-atmosphere capability, as well as a fully functional atmosphere control panel with pressure regulator, flow meter and manual shutoff valve.

The furnace is insulated with 2.5-inch lightweight insulating firebrick and backed up with 2 inches of insulating board. The bottom is reinforced with a high-density calcium silicate for extra support for the load weight. Elements are very evenly spaced around the chamber, and there is a manually operated vertical door. Included is a NEMA 1 control cabinet with a Honeywell program controller, high-limit backup system, thermocouples, fusing and all interconnection wiring. Power control is accomplished with quiet two-zone, long-lasting solid-state contactors.