Kobe Steel, Ltd.'s aluminium side-impact door beam is being used in Mitsubishi Motor Corporation's Lancer Evolution VIII MR, a four-door sports sedan that went on sale earlier this year in Japan. This is the first time the aluminium extrusion has been adopted by Mitsubishi. In comparison to door beams made of high strength steel sheet rolled into the form of a pipe, aluminium side-impact beams reduce the weight of a four-door car by roughly 3.5 kg.
Owing to growing demand, production of 100 metric tons a month is expected to rise to 150 metric tons a month in the second half of fiscal 2004. Aluminium side-impact beams have been used in Japanese cars for over 10 years in 10 models amounting to 1.7 million automobiles.
Door beams protect passengers by absorbing the energy in side collisions. While side collisions in traffic accidents occur relatively less frequently, side collisions of passenger cars by SUVs, which are growing in popularity, can result in serious accidents, heightening the necessity for side-impact beams. Aluminium is drawing greater attention as automakers seek to make lighter cars to improve mileage and reduce emissions while maintaining safety.
Kobe Steel is Japan's only manufacturer of the aluminium beams. It holds 15 patents in Japan, five in North America, and five in Europe. In addition to domestic carmakers, Kobe Steel supplies a number of Japanese automotive transplants.
The first applications of the aluminium beams were in Honda Motor Co., Ltd.'s all-aluminium NSX and Nissan Motor Co., Ltd.'s Rasheen, an SUV. As Japan's top manufacturer of aluminium for cars, Kobe Steel aims to further expand applications of aluminium side-impact beams. Other automotive aluminium products that Kobe Steel makes are sheet for body panels and forgings for suspension systems.