L&L Special Furnace Co. Inc. supplied a high-uniformity pit-style furnace to a company that manufactures aerospace fasteners and supplies to a worldwide client base. The furnace, which was built in accordance with the AMS 2750E pyrometry specification, will be used for annealing. The fastener parts are placed in baskets and loaded by an overhead crane into the furnace. There are guide bars to ensure that the load is centered and cannot damage the furnace liner.
The annealing process occurs when parts are evenly heated to 1400°F (760°C) and held for a predetermined amount of time. Temperature uniformity is critical, and both ambient and load temperature must maintain ±10°F throughout the cycle. The furnace, which has been surveyed and is capable of ±10°F at 1750°F throughout the work envelope, includes a 5-hp, air-cooled turbo convection fan to aid in temperature uniformity. The system is controlled by Watlow controls and SCR power controls.