Company News, 2005-09-12, 11:01 AM
R-Class: ThyssenKrupp Stahl as development partner for body-in-white construction
This year's IAA will see the European debut of a vehicle that sets new standards in the sports utility vehicle segment the Mercedes R-Class. It is also an ideal example of how a steel producer can contribute to the development of a vehicle by doing more than just supply materials: ThyssenKrupp Stahl was involved in the development of the new R-Class from the first idea to the start of production in March 2005. The company not only advised DaimlerChrysler on the selection of steel materials for the Grand Sports Tourer and supplied many of them itself, it also took on responsibility for important parts of the production planning for the body-in-white as a development partner.
The materials concept
More than 60 percent of the body-in-white for the R-Class, which is being produced in Tuscaloosa/USA, is made up of high-strength and ultrahigh-strength steels. Crash-relevant parts such as the side members and cross members in the front section of the luxury SUV are made of advanced high-strength steels with strengths of 500 to 600 megapascals.
The complex-shaped upper side members, made from a dual-phase steel with a tensile strength of 500 megapascals, are a particularly good example of the good formability of these steels despite their high strength. These properties are made possible by a precisely controlled microstructure combining hard and soft components. For the side roof rail and the B-pillar reinforcement, an ultrahigh-strength steel alloyed with manganese and boron is used. This material is heated prior to forming, and then rapidly cooled after forming to provide a strength of more than 1,500 megapascals in the part.
Production planning and validation
With the NSB® NewSteel Body, ThyssenKrupp Stahl AG provided ample evidence that its capabilities along the body-in-white process chain also include expertise in production planning and production technology. As part of the ThyssenKrupp Group, ThyssenKrupp Stahl also cooperates closely with companies from the Automotive segment on specific orders. The R-Class project was carried out in collaboration with ThyssenKrupp Drauz Nothelfer GmbH, one of the world's biggest service providers and equipment suppliers for automotive body construction. ThyssenKrupp Stahl was the lead company in the first development phase.
As well as support in the selection of materials, the R-Class order also involved the validation of production technologies at an early stage and the development of a body-in-white assembly layout. This gave ThyssenKrupp Stahl a direct influence on the design of the production lines in the Tuscaloosa plant. As slight size variances are possible at many different points during the assembly of the body-in-white, a so called tolerance concept is also needed to reduce and compensate for these variances so as to ensure that the overall body-in-white structure remains within tolerance. For this, ThyssenKrupp performed tolerance simulations and tolerance chain checks and proposed design solutions to meet DaimlerChrysler's high quality standards.
The new R-Class is being produced at DaimlerChrysler AG's Tuscaloosa, Alabama plant using components supplied from 13 American stamping plants. ThyssenKrupp Stahl visited these stamping plants, provided training for some of the employees and supported the die tryout process. The result of these perfect preparations was a smooth start of production at the Tuscaloosa plant.
ThyssenKrupp Stahl is exhibiting at IAA in hall 4.1, booth C50.