Heat Treatment Process in Metal Manufacturing
Heat treatment is a process that involved a combination of heating and cooling process which are timed, and they are applied on a metal or an alloy that is in solid state to make the materials gain a desirable property. The processes of heat treatment always aid in increasing the strengths of metals. The heat treatment can also be used to help in obtaining manufacturing objectives such as improving the materials’ formability properties and machining properties, restoring ductility of metals, recovery of grain size of different metal. The assignment will focus on the heat treatment processes that usually being used in the manufacture of camshaft, gears, bearings and bed ways on a lathe machine (Bonami, 2010).
Gears of cars
Gears should be tenacious on the inner side and hard on the outrider part to enable them to be to be durable and strong enough to resist external forces that are usually being applied on it. Gears are manufactured through the following heat treatment processes; carburizing, Induction hardening and Nitriding (Zhou, 2012). Carburizing is a heat treatment process used in low-carbon steel like S15CK. In a carburizing process, a metal surface is usually being penetrated by carbon compounds and gases such as methane and propane and the material is then taken through the processes of tempering and quenching to improve their hardness. The layer obtained after hardening process is 0.2mm to 2mm thick. Carburizing treatment is being performed after cutting the gear and their teeth formed.
Induction hardening is used for gears that are made of medium – carbon steel such as S45C. Induction hardening depends on the property of eddy current of causing heating effects when it is concentrated on a metal surface. The eddy current usually flows on an electrified gear material through the effects of electromagnetic induction. Nitriding is the other heat treatment process that is commonly used on gears made of steel that contains chrome and molybdenum. Nitriding is performed in the final stages of manufacturing gears, it is usually done at a temperature of 500 to 600 degrees celsius hence it causes no quenching cracks or metal distortion. The process of Nitriding gives hardness higher than carburizing (Zhou, 2012).
Camshaft
The preferable method of heat treatment for hardening camshaft is induction hardening. Mainly because the method can be easily integrated into the planned production line thus assist in maximizing the production (Pellizzari, 2010). The method also allows each camshaft to be individually hardened with known and controlled process parameters. Induction hardening also has more heating efficiency compared to the furnace method because it only generates heat when needed.
Bearings
The heat treatment processes recommended for bearings are tempering and hardening. Hardening helps in achieving the desired strength of bearing while tempering, on the other hand, helps to reduce internal tensions and the fragility of the bearings that have been hardened (Semenov, 2014). The outcome of the hardening process depends on the dissipation speed of heat. Steel bearing always has a high cooling rate of about 650oC. cooling in water is usually faster and it is preferred for hardening steel bearings (Stancekova et al., 2016). Various ingredients are usually being added to the quenching water mainly to increase or slow down the cooling rate of water. Tampering and hardening are the important heat treatment process of manufacture of bearing because they ensure dimensional stability and achieve the required hardness (Bonami, 2010).
Bed Ways on Lathe Machines
Bed ways of a lathe machine are the large base part that usually supports and connect the various parts of the lathe machine.it ensures that all these parts have an exact relative position to work appropriately Bed ways of lathe machine are being produced through flame heating that involves substantial heating and cooling of the elongated bed ways surface (Stancekova et al., 2016).
In conclusion, the heating and cooling of lathe machine bed ways are being done at a controlled temperature to ensure that the outcome has the desired quality such as strength, durability and corrosion resistance (Semenov, 2014).
References
Bonami, G. (2010). Heat treatment. New York: Nova Science Publishers.
Pellizzari, M. (2010). Influence of deep cryogenic treatment on heat treatment of steel and Cu–Be alloy. International Heat Treatment and Surface Engineering, 4(3), pp.105-109.
Semenov, M. (2014). Computational Evaluation of Cyclic Strength of Carburized Gears from Heat-Resistant Steels. Metal Science and Heat Treatment, 56(7-8), pp.428-433.
Stancekova, D., Steklac, D., Petru, J., Zlámal, T., Sadilek, M., Janota, M. and Kordik, M. (2016). Influence of Machining and Heat Treatment on Deformations of Thin-Walled Bearings. Materials Science Forum, 862, pp.49-58.
Zhou, X. (2012). Manufacturing engineering and process. Durnten-Zurich, Switzerland: TransTech Publications.
