High Strength Steels for Automotive applications: Recent Trends and Experience at Tata Steel 2005-26-333

The cars need to meet the new legislative regulations on green house emissions, safety, and durability and acoustic comfort coming into force in near future. At the same time there has been a strong demand from the market to produce cars, which offer better fuel efficiency and hence low cub weight in combination with better crash performance. High strength steels provide a convincingly reasonable solution to the above conflicting requirements by proposing the concept lightweight design. Various new lightweight materials like aluminum, magnesium and plastics have been proposed but steel still constitutes more than 70 % of BIW weight and have remained a preferred material based on issues like cost, recyclability, reparability, reliability and other manufacturing concerns viz. formability and weldability. Various high strength steels grades both hot rolled and cold rolled are being developed worldwide to provide flexibility in design to the automobile manufacturers in order to meet their product requirements. However, issues like formability and weldability requirements as well as rolling mill constraints involved in development of high strength sheets need to be resolved.

Tata Steel has been perusing aggressive product development plans to produce thinner gauge high strength steels for automotive application. With a major focus on Indian automotive market, Tata Steel so far, has been able to successfully develop high strength steel grades like TRIP, DP, BH and IF-HS for varying combination of properties for various applications in automobiles. While some of them have already been commercialized, few of them have been experimentally developed and waiting for commercialization.

This paper presents a brief overview of the trend of use of high strength steels and Tata Steels' experience in development of such new steel grades.