Model 7GT-K36 Inert Atmosphere Furnace

September 13, 2013

Lucifer Furnaces Inc. has designed and manufactured a heat treating box furnace for use with inert atmosphere for stress relief of springs under nitrogen atmosphere. Model 7GT-K36 has a working chamber area of 12"H x 12"W x 36"L and heats to 2100°F with 15 KW power. GT Models are designed with a continuously welded furnace shell for operation with a positive flow of inert atmosphere. This furnace is fabricated with 2.5" insulating firebrick and 2.5&" mineral wool insulating block for superior thermal efficiency.

Heating elements designed with V-grooved radiant panels and low watt density coiled elements line the side walls and are easy to replace. The work load is supported by a 1"-thick hearth plate, which protects the floor insulation and provides a flat work surface. An inlet port is mounted through the rear wall of the furnace and an adjustable outlet port with gas cock is located through the front left side. Temperature for this Series 7000 GT Inert Atmosphere Box Furnace is controlled by a Honeywell DC 2500 microprocessor time proportioning controller. With a double pivot horizontal swing door, the operator is kept safe from the door's hot face at all times.

Additional safety features include a microswitch to disengage power when the door is opened and an overtemperature safety system for automatic furnace shutdown in the event of a high temperature excursion which is important for unattended furnace operation. This particular unit is complete with a flowmeter and circular chart recorder; it will be used as an addition to an existing Lucifer Furnace at a customer's facility to reduce the residual stress from manufacturing. Stress relieving reduces the internal stress from manufacturing and increases the mechanical strength of the spring.

Related Glossary Terms

  • flat ( screw flat)

    flat ( screw flat)

    Flat surface machined into the shank of a cutting tool for enhanced holding of the tool.

  • relief


    Space provided behind the cutting edges to prevent rubbing. Sometimes called primary relief. Secondary relief provides additional space behind primary relief. Relief on end teeth is axial relief; relief on side teeth is peripheral relief.

  • residual stress

    residual stress

    Stress present in a body that is free of external forces or thermal gradients.

  • stress relieving

    stress relieving

    Annealing designed to relieve internal stresses caused by machining, welding, casting, cold working, quenching or normalizing.