L&L Special Furnace Co. Inc. manufactured and shipped a retort furnace to a northeast U.S. manufacturer of motor laminations. The furnace has a work zone of 17 inches square, and the typical load weight is 250 pounds. The retort is removable to achieve the required aggressive cool-down curves. All thermal data is collected and stored from each run through a PLC-based control system. The furnace, which was built in accordance with ASTM standards, was set up to perform both hardening and oxidation during a single heating cycle. To accomplish this, L&L outfitted the furnace with a custom-developed Honeywell control system.
The laminations are deployed on motors, primarily for government-based aerospace products. Annealing of silicon iron and similar laminations are treated in a pure dry hydrogen atmosphere. There is also an oxidization process that can provide a thin oxide coating layer for improved durability and resistance.