Advanced Steel
Steel companies such as POSCO and Hyundai Steel that are manufacturing automotive steel sheets are putting in a lot of effort to develop premium automotive steel sheets. As global automobile manufacturers are focusing on high efficiency engines and lightened car bodies in order to enhance fuel efficiency and minimize emissions, automobile steel sheet materials are changing.
Accordingly, steel companies including POSCO and Hyundai Steel are concentrating on developing new products with more strength and less weight than existing steel sheets by new manufacturing methods such as heat treatment and alloying. Especially as final automobile manufacturers are more frequently using new materials like carbon fiber, aluminum and magnesium alloys to substitute for steel in their future-concept cars, the steel industry is busy preparing for this change.
According to the industry on July 27, if a car body is lightened by 10 percent by using lighter steel sheets, the average fuel cost goes down by three to seven percent, and carbon dioxide emissions are diminished by 13 percent.
POSCO is promoting Twinning-Induced Plasticity (TWIP) steel for next-generation automobiles. TWIP steel enables complex-shaped automobile components to be easily processed, fuel efficiency to improve, car bodies to be lightened, while its enhanced strength safeguards a car's occupants in an accident. POSCO has already established a mass-production system for advanced high-strength steel (AHSS), which has a tensile strength of 490MPa. AHSS endures a maximum of 50 kg of weight per mm2, but is even thinner than the 270-340 MPa automobile panels commonly used. This is a critical material for the weight lightening of automobiles.
Hyundai Steel ultra high strength steel, which endures 60-120 kg of external weight, is also a critical weight lightening material for automobiles. In fact, the LF Sonata recently launched by Hyundai Motors, which is 51 percent ultra high strength steel, is 29kg lighter than the YF Sonata, which is only 21 percent ultra high strength steel. Hyundai Steel is also developing a high wear resistance aluminum/silicon alloy and Hot Rolled Galvanized (HGA) automobile steel sheets. Aluminum/silicon alloy steel sheet lines were created last March, and mass production started in May.