The use of heat to treat objects is a very old manufacturing process. Heat is a powerful agent for metamorphosis. All materials change when we subject them to heat. In the manufacturing industry, heat is used to treat objects like metals and glass to alter their properties. Sometimes we obtain an entirely new product with heat treatment. Heat treatment furnaces are the most often used equipment for this purpose.
Heat treatment furnace manufacturersare in facts an important part of many industries — from metallurgy, steel, automotive and aeronautics. Heat treatment furnaces are preferred for many reasons. Furnaces can reach very high temperatures. Modern furnaces allow relatively easy movement of the treated product and better control of temperature.
Functions in a heat treatment furnace
There are many ways we can use heat on objects. The temperature and method of heat treatment can give us varying degrees in the material properties of the same object. The transformation of the object depends on the temperature we use to heat it, how fast we heat it, the duration of the treatment, the temperature to which it is cooled and how fast it is cooled. The different methodologies determine the way heat acts on an object and changes it.
There are many reasons for heat treatment. We can make an object tougher, harder, improve its ductility, machinability, grain structure, wear resistance and remove residual stress.
Procedures in heat treatment
Given that tweaking the way we administer heat can radically change the resultant product, it is not surprising that there are different procedures in heat treatment. Some of these are:
Decarburisation: As the name suggests, it is a process by which we reduce the carbon content in an object. In metallurgy this is usually used to decarbonize steel. When the metal is heated to a very high temperature, the carbon in it reacts with hydrogen or oxygen. This results in removal of carbides, which softens the metal. It is an important process in steelmaking, especially for electrical and stainless steel. A heat treatment furnace manufacturer uses carburizing technology in the removal of carbon form the product.
Annealing: In annealing a metal is heated to a specific temperature, held there for some time and then cooled in a controlled manner. Annealing can change the physical and chemical properties of a product, reducing its hardness and making it more ductile. In the annealing procedure the object’s crystal structure changes as it recrystallises and then becomes stable. The change in the structure of the metal can make it softer, less brittle and more amenable to shape or formed. For the process, a heat treatment furnace manufacturer will ensure that the heating and later cooling can be controlled and carried out in a phased manner.
Quenching: In quenching we take a metal to a very high temperature and then cool it very quickly by quickly immersing it in water, brine or oil. This method stops the carbon from moving in the metal’s crystal structure and forming carbides and softening it. Non-ferrous metals however, become softer. The rapid cooling prevents any phase transformation. It is most commonly used to harden steel and cast iron alloys. The rate of cooling can change depending on whether we want thorough hardening or surface hardening.
Tempering: In tempering we heat a metal to a specific temperature below the critical point. When ferrous metal is subjected to tempering, it increases its toughness, which also boosts its ductility and strength. It is a process by which we can make tough metals more ductile. Heat treatment furnace manufacturers typically use ceramic heating elements in a tempering furnace. The control of temperature is critical here.