Pit Type Tempering Furnace | Industrial Heat Treatment for Uniform Metal Hardness

The pit type tempering furnace is a batch-type heat treatment furnace with vertical deep-well cylindrical structure. The furnace body is either embedded underground or installed upright on the ground. Workpieces are hoisted vertically into the furnace chamber in baskets or bundles from the top opening. As a branch of pit resistance furnaces, it is mainly applied for tempering, stress relieving and hardness adjustment of metal workpieces after quenching.

1.Workpieces are vertically lifted into the hearth via an overhead crane or lifting hook, then the furnace lid is tightly sealed.

2.Electric heating elements are arranged around the cylinder wall, and a high-power hot air circulation fan mounted on the furnace top drives forced hot air circulation to ensure uniform temperature throughout the entire chamber.

3.After constant-temperature holding, workpieces are taken out for air cooling or slow furnace cooling to eliminate internal quenching stress, reduce brittleness and stabilize dimensional accuracy as well as hardness.

1.Furnace Body: Vertical cylindrical steel structure lined with refractory and thermal insulation materials.

2.Heating System: Resistance heating strips or tubular heaters mounted on side walls with zoned temperature control.

3.Hot Air Circulation System: Vertical stirring fan at furnace top for vertical forced airflow circulation, with temperature control accuracy of ±3~5℃.

4.Furnace Cover & Lifting Unit: Sealed furnace cover matched with overhead crane and lifting tools for bulk loading and unloading.

5.Electric Control Cabinet: Intelligent PID temperature controller to set segmented curves of heating up, heat preservation and cooling down.

1.Large loading capacity for mass production

Vertical cylindrical chamber allows bulk loading with baskets, suitable for mass tempering of gears, bolts and long shafts to improve production efficiency.

2.Uniform temperature by forced hot air circulation

Top-mounted circulating fan drives hot air flowing inside the furnace, minimizing temperature difference and ensuring consistent hardness of finished workpieces.

3.Avoid deformation for long shaft parts

Slender workpieces like piston rods, lead screws and transmission shafts are suspended vertically during heating to prevent bending deformation caused by horizontal placement.

4.Good sealing & optional protective atmosphere

Tight sealed furnace cover supports nitrogen or dissociated ammonia filling to reduce oxidation & decarburization for bright workpiece surface. Equipped with PID precise temperature control.

5.Wide processing versatility

Customizable heating & cooling curves to complete low/medium/high temperature tempering for carbon steel, alloy steel and die steel.

1.Auto parts: transmission shafts, gears, half shafts, fasteners for automobile chassis;

2.Standard fasteners: high-strength bolts, nuts, studs and rivets;

3.Construction & hydraulic machinery: piston rods, cylinder shafts, engineering pins & gears;

4.Bearing industry: bearing rings, roller shafts and transmission gear parts;

5.Hardware & mould: stamping dies, cutting tools and precision hardware;

5.Petroleum, wind power & railway spare parts.