Heat Treating Steel
Steel heat treating is a process that is used to harden or soften steel by heating or cooling the metal until it reaches the desired point of hardness. In steel, like all metals, the structure and composition of the grains, or crystallites, determines the overall mechanical qualities of the metal. Heat treating is an energy-intensive process that changes this atomic structure, thereby also changing its mechanical behavior. Although many metals go through the process, steel is the most commonly heat-treated metal.
Several critical techniques are used in the steel heat treating process, including annealing, quenching, and tempering. Annealing is a process by which steel is heated and then cooled very slowly, leaving the metal soft and ductile. Quenching, on the other hand, refers to the rapid cooling of steel that can be used to increase the metal's strength. Tempering is also performed to strengthen steel; in tempering, the metal is heated to extreme heat, between 400 and 600 degrees Celsius, and maintained at this temperature until the carbon diffuses to produce bainite or pearlite.
Many different kinds of equipment are used in the heat treating process. Some of these tools include furnaces, torches, salt bathes, heating blankets, and lasers. Heat treating is used to make a variety of steel goods used in the automotive, construction, manufacturing, and tool and die industries. Some examples of heat-treated steel goods include knives, swords, gears, medical equipment, valves, drive shafts, and bearings.