Widely Used Industrial Materials

Industrial applications require that the materials used for products are of superior quality. One of the most widely used industrial materials is steel since it has various properties suitable for different applications. One common method of improving steel is through heat treatment.

Heat treatment is a controlled process used to modify the microstructure of materials to improve its properties [1]. This involves heating and cooling the material to change its crystalline structure and composition. The amount of heating and cooling done to achieve certain properties of steel can be dictated by the iron-carbon diagram which shows the different phases present in different carbon content and temperature and the continuous cooling transformation diagrams which shows what phases are formed with different cooling rates. The temperatures used, rate of cooling, and extent of heating are significant factors to heat treatments [2, 3].

Heat treatments alter the amounts of the different phases in steel to improve its properties. The presence of martensite provides steel with distinct hardness and brittleness while austenite provides steel with ductility. The presence of cementite increases the toughness of steel and increases it further with grain size growth. The relative amount

Also known as drawing, tempering involves reheating steel to a certain temperature below critical and letting it cool. This is done since as-quenched steels are very brittle. Tempering is done to toughen steel so that it can be easily used for applications. As any temperature below critical may be used for tempering, there are many variations in properties that can be produced. Having a higher tempering temperature as well as tempering time increases the toughness of the steel. Higher temperatures and longer time promotes the nucleation of cementite and ferrite through diffusion as well as grain growth of the grains, thus lowering strength and increasing toughness