Kobe Steel and Toyota Motor Develop Processing Technology of High Tensile Steel Sheet

Kobe Steel announced on Friday the firm developed processing technology of high tensile steel sheet in cooperation with Toyota Motor. The technology is named reverse bottoming method that can largely reduce remnant stress of 980MPa class super high tensile steel sheet. The high tensile steel sheet processed by this method was adopted to B pillar of Toyota’s Lexus CT200h and the car was launched in January 2011. Toyota evaluated the technology that contributes to weight saving and gave Muss Innovation Award 2010 at the suppliers’ meeting in February 2011.

Remnant stress causes camber back in press working of 980MPa class high tensile steel sheet. Kobe Steel and Toyota Motor have tried to find out the new processing method in current several years.

Reverse bottoming method presses steel sheet from two directions that can largely reduce remnant stress. Automobile makers now can use 980MPa high tensile steel sheet to B pillar though they could use only 440-590MPa steel sheet. Toyota Motor could reduce the component number by usage of high tensile steel sheet and lower car weight by 35% and production cost by 25%.

Kobe Steel has recently promoted global expansion of high tensile steel sheet business including introduction of a continuous annealing line at PRO-TEC in the U.S.A. The firm plans to double the sales volume of above-590MPa high tensile steel sheet worldwide in fiscal 2015 ending in March 2016.