The pit-type furnace is a prominent type of furnace used in modern mechanical manufacturing; it is particularly effective for the spheroidizing treatment of steel. This is largely because the equipment often operates with a protective atmosphere, ensuring high surface precision in the finished workpiece while effectively maintaining its toughness and rigidity. Given these advantages, pit-type furnaces are widely used in industrial production, and demand for them is increasing year by year.
Pit-type furnaces can be heated by gas, liquid fuel, or electricity. When gas fuel is used, multiple low-capacity burners are typically installed tangentially along the inner furnace wall; they are arranged uniformly-either in tiers or in a spiral pattern-to prevent flames from directly impinging on the workpiece and to ensure temperature uniformity within the furnace. For low-temperature tempering or when using oil fuel, a thin muffle wall is constructed inside the furnace chamber to separate the combustion zone from the heating zone; however, pit-type furnaces equipped with muffle walls tend to have higher fuel consumption.
