YOKOHAMA, Japan -- As part of a drive to shed weight and boost fuel economy, some Nissan brand vehicles will get the ultra-high-strength, lightweight steel that debuted in the Infiniti Q50 in January at the Detroit auto show.
Nissan Motor Co. says that by 2017, it aims to use so-called advanced high-tensile-strength steel, including this ultra-high-strength kind, in a quarter of all new-vehicle body parts.
The goal is to use lighter steel that can shave vehicle curb weight -- thereby improving fuel efficiency and reducing emissions -- while delivering the same performance as ordinary steel.
In general, a 15 percent reduction in vehicle weight cuts carbon dioxide emissions 5 percent, says Shinsuke Suzuki, Nissan's general manager for body engineering.
Automakers are racing to lighten their fleets in an attempt to meet increasingly stringent emissions standards.
Nissan, for instance, cut 73 pounds from the Nissan Altima when it redesigned the mid-sized sedan for the 2013 model year. And engineers cut 176 pounds from the Nissan Leaf electric vehicle with its 2012 redesign.
"In order to comply with these regulations, we are working hard to reduce weight," Suzuki said. "This is increasingly urgent."
A key strategy for Nissan is the use of more advanced high-tensile-strength steel.
Today, the company uses such steel in 9 percent of its new body parts, by weight. Nissan aims to raise that to 25 percent in 2017. The figures are measured as a ratio of overall component weight. The target applies only to new or redesigned vehicles.
Advanced high-tensile-strength steel is generally considered steel with tensile strength of more than 780 megapascals, a measure of pressure, stress and tensile strength. Tensile strength measures the force required to pull something until it breaks.
Ultra-high-tensile steel, which has tensile strength of about 1.2 gigapascals, is strong but normally too brittle to be stamped into intricately shaped components.
Nissan has developed a new grade of ultra-high-tensile steel and a new manufacturing process that allows its use in complicated parts. That allows Nissan to use ultra-high-tensile steel for parts that had been off limits, such as roof pillars. The result is weight loss without strength loss.