Slimmer design, lower weight, same performance. Too much to expect at the same time? Yet, this feat was accomplished by combining two innovative manufacturing processes as part of the ‘InCar®plus’ project Slim A-pillar. They can also be applied to other components.
Look left, look right, begin to accelerate, and then it happens – crash! Some motorists do not obey the right-of-way or overlook other cars when making turns nearly 290 times each day. One reason why is that A-pillars, which establish the vertical support between the windshield and side windows, have become so wide that they can even impair a driver’s field of vision. Manufacturers are stuck in a predicament. Modern car bodies need to ensure a clear view of the road on the one hand, and on the other, they need to be stable enough to withstand even the hardest of crash tests.
thyssenkrupp Steel Europe, together with cooperation partner Linde + Wiemann, has developed a solution for this problem. The A-pillar has become considerably slimmer and ten percent lighter, while remaining as tough as other models available now. “The greatest advantage is that we were able to improve the field of vision greatly. It was made possible by reducing the angle of vision that was impeded by 34 percent,” explains Jörg Gorschlüter.
He heads the ‘Slim A-pillar’ project that was set up at thyssenkrupp as part of the InCar®plus development alliance. “The manufacturing processes can be transferred to many other car body components, such as longitudinal members and B-pillars.” The A-pillar is the most complex component on the car body, he says. “With this example, we show something that had previously not been possible with the technology available.”
Two modern technologies have been combined to manufacture it. A rounded, pipe-shaped semi-finished product is created in various cross-sections in a cold process using T3® technology. The formed blank is made of MBW®1500. Then we subject it to a special hot forming process that gives the part its final shape. This ACCRA® process leverages the advantages of hydroforming and press hardening. Linde + Wiemann has developed the process further and recently took 2nd place for the A-pillar in the 2015 Steel Innovation Awards.
“The company has many years of experience as an important systems supplier for major automotive manufacturers and has been one of our customers for years,” explains Gorschlüter. Which also explains why the cooperation emerged three years ago. It is now possible to create extremely complex component geometries by linking both technologies.
The new A-pillar is not only slimmer, it also reduces vehicle weight by 3.2 kilograms, without affecting performance. The manufacturing costs are slightly higher, yet they are absorbed by the savings in material to a great extent. The lightweighting costs are only €1.57/kg. Developers have designed the A-pillar in a way that it can be flexibly adapted to the needs of automotive manufacturers. The length can vary and the shape can be transferred to other models. Further, it can be manufactured under traditional production conditions and in standard cycles.