Complex, Delicate Steel
Hyundai Steel announced on Oct. 23 that the company succeeded in the development of a tough 32 kg strength steel plate that can be used in the side-outers of vehicles for the first time.
Side-outers are external plates that determine the design of the sides of cars. Soft 28 kg or lighter-strength steel sheets have been used by all automakers around the world, since side-outers necessitate complex and delicate forming processes.
Higher strength is a big advantage of the 32 kg strength steel sheets developed by Hyundai Steel. The new steel sheet allows a vehicle to better endure external shocks when the vehicle is parked, loaded with packages, or if a pebble on the road bounces and hits the vehicle.
Generally, the stronger a steel sheet is, the lower its formality becomes. The steel company achieves a feat of enhancing both the strength and formality of a steel sheet via the optimization of constituents of materials, precise constituent combination control technology, and rolling technology.
In actuality, 20 kg strength steel sheets have about a 43 percent elongation, while current 30 kg or higher strength steel sheets show an elongation of 40 percent or lower. So the latter cannot be used in side-outers that require high-elongation steel sheets. But the newly developed 32 kg strength steel plates can go into side-outers, since they are 1.2 times tougher than current 28 kg strength and can realize an elongation of 43 percent or higher.
Materials for car chassis are high-grade steel sheets that can satisfy strict quality standards among cold-rolled steel products nicknamed “the crown jewel of steel products.” It usually takes ten years from the development of a new high-grade steel sheet to its commercial use in automobiles. But Hyundai Steel completed the development of the new product in three years, after starting to develop it in 2012. The company is now preparing to mass produce the innovative steel sheets to apply the product to new cars that will be launched next year.
“Previously, Japanese automakers applied high-strength steel sheets to side-outers by partially welding them on side-outers. But it has been unprecedented to realize a whole structure with single-bodied high-strength steel sheets like this time,” said a representative at Hyundai Steel. “This achievement will expedite research on developing lighter cars, which elevates steel sheets’ strength and formality for automakers at the same time.”