An Automotive body depends on the manufacturer’s considerations with the legislation and regulation, and some on the requirements of the customers. Most of the manufacturers prefer featured materials which are lightweight, economic, safety and recyclability.
The main elements of selecting material especially for the body is involved in a wide variety of characteristics such as thermal, chemical or mechanical resistance, manufacturing efficiency and durability. Steel stands as the first choice for manufacturers with all the required characteristics. The improvement or development in the steel industry made the steel stronger, lightweight and stiffer than the earlier. Steel includes not only vehicle bodies, but also engine, chassis, wheels and many other parts. Iron and steel develop the critical components of structure for the bulk manufacturing of vehicles and are low-cost.
The best reason for using steel as a body structure is its natural capability to absorb the impact energy produced in a crash.
Aluminium is widely used in the automotive industry, in chassis and body structure. Use of aluminium can possibly decrease the weight of the vehicle. Its low weight and high specific energy absorption and precise strength are its most significant characteristics. Aluminium is resistant to corrosion, but according to its low modulus of flexibility, it cannot substitute steel parts. Hence those parts need to be re-engineered to adopt the same mechanical strength.
Aluminium usage in the automotive industry has vastly grown within less period of time. In the automotive industry, aluminium castings have been used for pistons, cylinder heads, intake manifolds and transmission. In chassis applications, it is used as wheels, for brackets, brake components, suspension, steering components and instrument panels. Aluminium is used for body structures, finishing and exterior attachments such as crossbeams, doors or bonnets.
Latest improvements showed that 50per cent of the steel is saved for the body in white by the substitution of steel by aluminium. This can result in up to 20-30 per cent reduction in the total weight of the vehicle.
Magnesium is another light-weight metal that is growing increasingly next to aluminium in automotive engineering. It is 33% lighter than aluminium and 75% lighter than steel elements. Magnesium components have many mechanical disadvantages that need a unique design for utilisation to automotive products.
Magnesium has lower tensile strength, fatigue strength, and creep strength compared to Aluminium. The modulus and hardness of magnesium alloys are lower than aluminium, while the thermal expansion coefficient is greater. As it has low mechanical strength, pure magnesium cannot be used, must be alloyed with other components. The most common alloying components for room temperature applications is Mg-Al-Zn group, which include aluminium, manganese, and zinc.