Heat Treating Furnaces
Heat treating furnaces heat a material and then bring it to a desired
temperature. From there the material is cooled, which allows the furnace
to instill increased strength, or aging within the material. This
allows manipulation of the material to alter the physical, chemical and
mechanical properties. The physical properties most often refer to how
hard or soft the material is. Heat treating furnaces add billions of
dollars per year in value to metal products, especially steel and
nonferrous products, by imparting specific properties to the parts.
These properties are often critical to the proper function of the
Some of the industries that are served by heat treating furnaces include pharmaceutical, automotive, packaging, assembly, electronics and textile. Techniques used by heat treating furnaces include precipitation strengthening, annealing, aging, quenching, tempering and selective hardening. Hardening can be broken down further to differential, flame, induction or case hardening. Precipitation strengthening involves changes in solid solubility as temperature varies. Annealing can be used for normalizing or stress relieving and comprises the processes of heating, holding temperature and then cooling in order to accomplish a specific state for the material being heated. Aging or precipitation hardening results in a softer metal. Quenching is quickly cooling from a high temperature. Tempering is often used on brittle materials to make it tougher, it can also be used to manipulate the color of the metal. Case hardening involves making the surface layer of a steel material substantially harder through heat treating.
Heat treating furnaces employ a process that involves three steps. First, the part is heated to a specified temperature (up to 2400.25ºF). It is then held at that temperature for the required amount of time, which may be as short as a few seconds or as long as 60 hours. Finally, the part is cooled either in the furnace or by quenching methods, depending on how quickly the part needs to be cooled. Things to keep in mind when purchasing are uniformity, control, airflow and rate of rise. Uniformity is ensuring the temperature is the same throughout the system. Control regards how easily the system is monitored and adjusted. Airflow refers to the type of ventilation you want/need. Finally, rate of rise regards to how fast you want to be able to increase the temperature.