| Abstract: |
During the last two decades several automotive companies all over the world tried to develop a thermal spray process for steel deposits in aluminum cylinder bores, trying to bring it into mass production. Only few, however, managed to achieve this goal. Regarding Germany, this technology is more prevailing than in other parts of the world. Following the trends and efforts of the last decades of enhancing fuel efficiency, this technology is the next step. Therefore, GROB-Werke have standardized and integrated their GROB Thermal Spray process ( GTS ) into their engine block production lines, resulting in a turnkey solution for the mass production of super-thin steel deposits in aluminum cylinder bores. GTS offers several advantages over other applications. Due to the versatility of this process we are able to adjust the properties of the deposit microstructure or microhardness to different engine architectures and cylinder bore geometries. Depending on the variation of spray parameters, the GTS steel deposit can be engineered to topographies which achieve top values considering tribology, thereby reducing fuel consumption. Regarding profitability the system (process & machine) offers an optimum in investment, operational expenditure, cycle time, availability and reliability. The standardized GTS process consists of an entire process chain, creating a cylinder surface with best tribological properties. The activation of the aluminum cylinder bore is achieved by mechanical profiling. The geometry of this profile is designed with special regard to the creation of a particular microstructure within the deposit. Both, microstructure and microhardness, are controlled via the process parameters in a way, that the interplay between mechanical preparation of the deposit on a CNC machining center and a final surface machining process step results in a precise, low-friction and wear resistant cylinder surface, even for the operation with aggressive fuels (sulfuric, alcoholic ingredients). The complete quality control plan for every production step ensures the robustness of the production chain.
|
|
