Mazda Motor Corporation has become the first car manufacturer to successfully develop vehicle components using 1,800 MPa ultra-high tensile steel. This super-strength steel will debut in the all-new Mazda CX-5 compact crossover SUV that will go on sale in 2012.
Mazda's new production technology uses 1,800 MPa ultra-high tensile steel to fabricate bumper beams, which fit inside the front and rear bumpers and minimise damage in the event of a collision. The bumper bars are 20 percent stronger and 4.8 kilograms lighter than previous versions and are a key part of Mazda's next-generation, lightweight and highly rigid vehicle architecture. The new body-architecture was developed as part of Mazda's breakthrough SKYACTIV Technology programme and the CX-5's bodyshell incorporates a new energy absorbing structure as well as expanded use of high-tensile steel to reduce weight.
The new bumper beams were developed in collaboration with Sumitomo Metal Industries Ltd and Aisin Takaoka Co Ltd. The use of high tensile steel enables vehicle parts to be thinner yet still retain the same degree of strength as previous, thicker components. This leads to significant savings in vehicle weight.
Reducing the weight of bumper beams is particularly important because, as they are incorporated into the body structure at the farthest point from the vehicle's centre of gravity, outside of the wheelbase and adding to the polar moment of inertia, their weight has a considerable effect on dynamic performance and responsiveness. They must also be sufficiently strong to provide maximum collision protection. For these reasons, devising a method of mass-producing parts using stronger (ultra-high tensile) steel has been a high priority goal.
However, stronger materials are less pliant (more rigid) and therefore absorb less energy in a collision. To overcome this, Mazda conducted extensive research into how bumper beams deform in a crash, and created a new design that absorbs energy more efficiently. Additionally, in order to ensure the bumpers provide maximum strength in the CX-5, Mazda collaborated with Futaba Kogyo Co Ltd to optimize the welding techniques used in manufacturing the beams and to establish a reliable production process.
Going forward, Mazda remains committed to reducing vehicle weight and improving dynamic performance, while also maintaining a high level of bodyshell rigidity and excellent impact resistance, in order to provide all its customers with genuine driving pleasure and outstanding environmental and safety performance.