Steels for Automotive Applications...

Steels for Automotive Applications Steel has been a leader in automobile applications since 1920s. Currently, steel is the primary material in body and chassis structures. It is the backbone of the entire vehicle. In cars, these days, steel makes up about 65 % weight. It plays many roles in present day vehicles. It protects occupants, provides positive driving experience, reacts to road loads, provides comforts, and provides attachment points to other components of the vehicle. As there is a high emphasis on greenhouse gas reductions and improving fuel efficiency in the transportation sector, the automobile industry is investing significantly in lightweight materials. The industry is moving towards the objective of increasing the use of lightweight materials. It is giving priority to the activities connected with the development of new materials, forming technologies, and manufacturing processes. The weight reduction is still the most cost-effective means to reduce fuel consumption and greenhouse gases. It has been estimated that for every 10 % of weight eliminated from a vehicle’s total weight, fuel economy improves by 7 %. This also means that for every kilogram of weight reduced in a vehicle, there is around 20 kg of carbon dioxide reduction. Over the last decade, a strong competition between steel and low density metals has been observed in the automobile industry due to the increasing requirements of passenger safety, vehicle performance and fuel economy. The materials used in automotive industry need to fulfill several criteria before being approved. Some of the criteria are the results of regulation and legislation with the environmental and safety concerns and some are the requirements of the automobile users. In many occasions, different factors are conflicting and therefore a successful automobile design is only be possible through an optimized and balanced solution. Around 65...

Aluminum in Steels

Aluminum in Steels  Aluminum (Al) is used for deoxidizing and grain refining in steels. It is a strong deoxidizer. It is also used as nitride former and as an alloying agent. Its ability to scavenge nitrogen (N) from steel makes it a useful addition in drawing quality steels, especially for automotive applications. Aluminum (Al) is being used as a deoxidizing element in steels for more than 100 years. Deoxidation of steel with Al is common practice today. Al plays an important role in secondary metallurgy. It forms aluminum oxide or alumina (Al2O3) alumina and decreases the amount of oxygen in the steel during the production of killed steels. Metallic Al is the most common addition agent. It is usually done in the form of notched bars, shots, pigs, small ingots, chopped wire, briquettes and other convenient forms such as coiled machine fed wire. Purity of deoxidation grade of Al is normally over 95 % with the main tramp elements being zinc, tin, copper, magnesium, lead and manganese. Coiled aluminum wire is usually made to 99 % minimum specification. A wire feeding machine is shown in Fig 1. Fig 1 Wire feeding machine Al is also added as ferro-aluminum which is a dense and highly efficient form of aluminum addition. Ferro-aluminum contains 30 % to 40 % Al and normally added in lump form. Al may be added to the steel making furnace, teeming ladle, Ladle furnace, continuous casting tundish or ingot mould. Each type of addition has its specific purpose, and each addition produces its own characteristic results. Al is a very powerful deoxidizer, but has a disadvantage because of its low density. The density of liquid aluminum at steelmaking temperatures (1600 deg C) is about 2.0 tons/cum while the density of steel at...