Over the last decade average weight of mid size car has reduced from 1400Kg to 1150Kg resulting in reduction of 18% of total car weight. Similar trend is also witnessed across all segments of passenger car. This was possible due to implementation of High Strength Steel (HSS) and Advanced High Strength Steel (AHSS) in automotive body structures. Mounting energy crisis, stringent emission law and strict safety rules have guided car manufacturers to improve strength/weight ratio of the vehicle, thereby promoting application of HSS and AHSS steels in the car body.
Automotive and Transport sectors are making increasing use of stainless steels to reduce weight, improve aesthetics, enhance safety and minimize life cycle cost. Characterized by superior fire and corrosion resistance, they ensure safety and reliability. Since stainless steels exhibit superior combination of high strength, ductility, formability and toughness compared to other metals and alloys, the intrinsic weight of vehicle decreases and its load carrying capacity and fuel efficiency increases. Maintenance cost is naturally lower and stainless steel component at the end of its long life is easily recycled.
In automobiles, stainless steels are most extensively used for exhaust systems. To improve efficiency, the designs for these components are becoming very complex and performance criteria are getting tougher. Since corrosion resistance remains vital for this application, appropriate titanium, niobium or dual stabilized grades with very low interstitial content are used with choice of grade depending on operating conditions.
Buses, trams make extensive use of austenitic stainless steels for outer panels. On account of transformation induced plasticity, these steels develop very high strength coupled with good formability in cold rolled tempers and constitute ideal material for structural components. The exceptional strength to weight ratio and energy absorption capacity enables the designers to reduce weight and enhance crash worthiness while ensuring longer life span due to superior corrosion resistance.
As new austenitic, ferritic and duplex stainless steels are evolving, automotive and transport industry is intensively exploring their potential.
One of the important tasks for the 21st century is the maintaining of sound ecology. The reduction of the burden on the environment is an inevitable task assigned to industry. A direct contribution of the steel industry to the reduction of fuel consumption is the supply of steels enabling the lightening of automotive weight. There is a direct correlation between kerb weight of vehicle and fuel consumption. As a thumb rule, 10% of weight reduction will lead to 3% - 7% less of fuel consumption. To reduce the weight of the vehicle and thus energy consumption, the usage of high strength steel in auto-making is gradually increasing. Figure 1 shows the diagram representing the materials used for manufacturing cars. The trend showing that there is increase in kerb weight in the year 2000, this is due to implementation of stringent safety laws. Following that there is decrease in kerb weight. This weight reduction was possible by development of HSS and AHSS and stringent environment law.
For more details download brochure