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Date:
March 02, 2011
Tailored tempering: How cars are becoming lighter, safer and greener
Steel is the most important material in auto production, accounting for over 90 percent of the body on average 
ThyssenKrupp develops not only innovative materials and parts for the auto industry but also forward-looking manufacturing technologies. The latest example is called tailored tempering. Patented for ThyssenKrupp, the technology makes cars safer and eco-friendlier. It is particularly suitable for safety-relevant parts, designed to protect occupants in the event of a collision. Tailored tempering saves weight and hence fuel, reduces CO2 emissions, and protects the climate. It also enables car manufacturers to save money.
B-pillar in forming die 
Parts made by tailored tempering are hard and at the same time ductile. These conflicting properties are needed by crash-relevant parts to protect occupants in a collision. The B-pillar in the picture is one such part: The pillars connect the roof and floor in the middle of the vehicle. The upper two thirds of the pillar need to be hard to protect the occupants. The lower third needs to be able to absorb impact energy and deform in a defined way. To date, these requirements have been met by using reinforcements or making the pillars from separate parts of different strength. Tailored tempering makes production simpler, cheaper and environment-friendlier.
Thermal image of a B-pillar during tailored tempering 
Hard yet ductile: For that you need a special material and a special process. The material is steel alloyed with manganese and boron. When a steel like this is heated to over 800 degrees, cooled rapidly and simultaneously formed, the result is an extremely strong part. ThyssenKrupp has refined this process and uses forming dies that are heated at certain points. Where the die is hotter, the steel cools more slowly and remains ductile: The result is tailored tempering.
Dr. Franz-Josef Lenze (front) and Sascha Sikora: Tailored tempering specialists at ThyssenKrupp Steel Europe 
Tailored tempering is a technology with great potential. This is proven by the InCar research and development project for innovations in car manufacturing. In it, ThyssenKrupp engineers designed B-pillars that save up to 22 percent in weight and up to twelve percent in cost. CO2 emissions are up to 17 percent lower than with conventional parts. The new technology saves weight because components no longer need to be reinforced or assembled from separate parts. Auto manufacturers save money because these operations are no longer necessary. The first customer for the new technology is a German car manufacturer who will be using tailored tempered parts in a new compact car.

Press topic InCar