Jan 18 2016
TOKYO - Kobe Steel has devised new technology for attaching aluminum and steel in automobiles to improve fuel economy by making their bodies 20 percent lighter.
Full-fledged marketing to automakers will begin this coming spring, with hopes to apply the proprietary technology in new vehicles as early as 2021. Japanese automakers will be targeted first.
Aluminum, just one-third as heavy as iron but not as strong, is often used with steel to save weight in vehicles. Attaching these materials to each other normally requires specialized rivets or other fasteners, along with special robots.
Kobe Steels method uses existing equipment to put high-tensile steel and aluminum together. It can attach an aluminum roof to the roof railing, for example, or the suspension base to the front sides of the vehicle frame. The technology could reduce a midsize autos body weight from 250kg to 200kg, according to the steelmaker.
To better accommodate automakers needs, a special research team on attaching multiple materials will expand from 15 or so members to around 25 in a few years. Kobe Steel hopes that the new technology will fuel sales of aluminum and steel materials.
Emissions regulations are tightening around the world. Meeting U.S. requirements for 2025 will require a large auto to drop an estimated 15 percent of its weight. Along with improving powertrain systems, including engines, making vehicles lighter is a key challenge for automakers.
Japanese automakers have generally used more high-tensile steel to save weight, while Ford Motor of the U.S. has adopted an all-aluminum body for mainstay pickup trucks. Germanys Daimler has improved fuel economy by about 30 percent in its latest Mercedes-Benz C-Class series by using aluminum for half of the vehicle frame. Carbon fiber, strong but lightweight, is being used in electric vehicles in Europe.
Aluminum costs a few times as much as steel materials of the same weight, and carbon fiber more than 10 times as much. Kobe Steels new technology can keep the cost increase relatively small.
