High Strength Steel Sheets and Tailor Welded Blanks for Automotive Application

Frédéric Brun
Arcelor-Mittal

For the last 15 years, new constraints have emerged in the automotive industry, regarding safety and environmental performances as tremendous pressure on costs.

The Indian auto sector faces nowadays the same kind of tendencies with obviously and surely first of all high pressure on prices, but also environmental performances and oil-consumption related to the high and steadily rising price of oil. Safety performances are also requested by the market and safety regulation with more severe request of crash resistance will come in the coming years.

In that context, with a view to assisting the carmakers to design and choose the most value-adding steel solutions, Arcelor-Auto has developed not only a wide range of steels going from the Extra Deep Drawing qualities to the Advanced High Strength Steels but also Tailor Welded Blanks technology.

We have studied and designed a generic solution of B-Pillar function originally composed of three parts - B-Pillar Inner, Reinforcement and Stiffner. This study highlights 7 options of improvements using High Strength Steels presenting the same or slightly increased safety performances, cost-saving and/or weight-saving.

The feasibility of each alternative has been checked and assessed regarding its easiness and robustness, as its mass and cost. The 7 described options using high strength steels allow up to 30% of weight saving, but also up to 7% of cost saving. Among the 3 best solutions bringing weight and cost saving, one is using tailor welded blanks in high strength steel.

The use of tailor welded blanks has been booming in the automotive industry over the last 15 years. In the beginning the weight saving was the main driver but with the increased awareness of safety that developed during the nineties in Europe, the tailor welded blanks soon proved to be an efficient lever for improving crash resistance.

Bumper, rail, seat reinforcements or doors examples among others show that TWB use allows optimisation of the use of HSS grades. By reducing the location of HSS where it is strictly necessary, by optimising the use of steel through the nesting of the blanks, and by integrating reinforcements when it is possible, TWB technology allows to achieve in various proportions weight-saving, cost-saving and enhancement of the global performance of the function, taking full benefit from both TWB and HSS concepts.

Arcelor through TBA - Tailor Blanks Arcelor - masters the TWB technology from the design and the assessment (technical and economical) of the solutions to the production and the processing assistance to our clients, fully in line with the Steel Solution policy of the company.

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