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2010
Conference Paper
Titel
Reduction of wear by boron based multilayer coatings on forging dies
Abstract
The near surface area of forging dies is exposed to high mechanical loads. Additionally thermal and chemical stresses occur during the hot forging process. Depending on the number of forged parts several kinds of damage develop in the near surface area, which lead to initial failures of forging dies, Die wear is the main reason of initial failure with 70 % ratio. Additionally, thermal and mechanical cracks as well as plastic deformation occur. The abrasion resistance of the surface area of forging dies has to be increase in order to reduce wear. Therefore, different methods were examined such s the increase of the abrasion resistance by plasma nitriding and by coating with thin hard coatings (TiN, TiCN, TiC, TiBN and TiB2). These layers are applied to the forging die by using the plasma activated chemical vapor deposition (PACVD) treatment. A wear can be achieved by using a thermal steady boron multilayer coating. For the investigations the thicknesses and number of layer repetitions were varied. To receive realistic wear values under industry-related conditions, an automated eccentric press was used for the testing. After 3000 forget parts, the coatings were examined by tactile measurement, SEM and EDX analyses to characterise the occurring wear.