Temperature Sections of Pit-Type Tempering Furnace
① 650°C – Suitable for tempering steel parts and heat treatment of light metal parts.
② 950°C – Suitable for heating steel components—especially shaft-type parts—for normalizing, annealing, and quenching. When required by the process, a protective atmosphere can be introduced to reduce oxidation during heating.
③ 1200°C – Suitable for heating alloy steel components, especially shaft-type parts, for normalizing, annealing, and quenching within the 1200°C range. A protective atmosphere may also be introduced to minimize oxidation.
Structural Overview
Pit-type tempering furnaces (pit-type electric resistance furnaces) are mainly composed of:
- Furnace shell
- Furnace lining
- Furnace cover
- Furnace cover lifting mechanism
- Heating elements
The furnace shell is welded from angle steel and steel plate and formed into a cylindrical shape. The working chamber is a circular furnace cavity. By default, the furnace uses our independently developed “new-type monolithic combined lining,” but refractory bricks or pure fiber modules can be selected per customer requirements. Insulation material is filled between the furnace shell and the chamber.
Iron-chromium-aluminum alloy heating wires, wound into spiral-shaped heating elements, are placed on the support bricks on both walls of the furnace chamber. The top of the chamber is sealed with a furnace cover, which uses a manual pressure-lever locking structure. A thermocouple inserted through the thermocouple port on the furnace shell controls temperature.
If higher temperature uniformity is required, a furnace circulation fan can be installed on the cover. The fan forces airflow circulation from top to bottom, ensuring the workpieces are heated evenly.