The tempering furnace is
an oven used for tempering. The heating process can increase the toughness of iron-based alloys such as cast iron or steel. Metal is usually put in a tempering furnace after hardening, and then heated to a certain temperature to remove excess hardness.
Tempering furnaces are mainly used to increase the toughness of metal or cast iron tools by reducing the hardness of these products.
provide a range of temperatures because the hardness removed depends on the composition of the metal and the expected result of the product. The spring needs a higher temperature when placed in the oven, and harder tools need to be tempered at a lower temperature.