Heat treatment is the first consideration to be made when trying to change the properties of metals. This is a mechanical process that involves heating metal at a specific temperature with a standard cooling method to obtain the desired properties. Today you’ll get to learn about the heat treatment of metals and the theory behind it.
What is heat treatment?
Many sources have given their definition, which is very unsatisfying because most of their definition contains the heating and cooling of metals, which is quite correct but incomplete. So, what is the heat treatment?
Heat treatment is the process of heating metal without letting it reach its molten, or melting, stage, and then cooling the metal in a controlled manner to get the desired mechanical properties. Heat treatment is used to either make metal stronger or more malleable, more resistant to abrasion, or more ductile.
In the engineering field, heat treatment is a metalworking process that involves changing a material’s physical and sometimes chemical properties. It is also said to be a way in which the physical or mechanical properties of a metal are changed by heat and cooling methods without changing the shape of the working metal.
With any of these definitions, I’m sure you now have an understanding of what heat treatment means. Let’s move further!
Read more: Common types of metals and their properties
Purpose of heat treatment
The following are the purposes of heat-treating metals:
- To improve ductility and toughness
- Increase the wear and corrosion resistance of a metal.
- Improve electrical and mechanical properties.
- Homogenize the structure to remove coring.
- Spheroidize tiny particles.
- Improve machinability and toughness.
- Grain size refinement.
- Relieving internal stresses.
Heat treatment serves several purposes when it comes to metal, and these can be achieved in three stages. These three stages of heat treatment include heating, soaking, and cooling. Read the full post here.
Theory of Heat Treatment
Heat treatment can differ depending on the metal material, but there are three main differences in the process: the heating temperatures, the cooling rates, and the quenching types. Tweaking this process will get you the properties you desire. Well, heat treatments are often performed on metals containing iron, which are known as ferrous metals. Annealing, hardening, normalizing, and tempering are done on such kinds of metals. You can read about annealing here.
Proper heat-treating equipment will be required so one can accurately control the factors around heating, cooling, and quenching. For instance, the furnace must be the proper size and type to control temperature, including the gas mixture in the heating chamber, and you need the appropriate quenching media to cool metal correctly.
That is all for this section, where the heat treatment of metals is discussed. I hope it was helpful. If so, kindly share it with others. You can also read about the heat treatment of copper and aluminum here.