Optimised impregnation parameters of self-lubricating powder metallurgical components for cold bulk forming

In order to achieve an economical forming technology production, a well-developed lubrication technology is generally required. Within the scope of this work, further investigations on a novel self-lubricating forming process are presented. Powder metallurgical (PM) components were impregnated with lubricant to store the oil in their process-related porosity. In a subsequent forming process the resulting pressure forces the oil to leak out lubricating the process. In preliminary works it was found, that the required maximum forming load can be reduced up to 39 % by applying the new lubrication method. In addition, relative densities up to 99 % were reached after deformation. Based on this, in this contribution optimized impregnation parameters regarding the initial porosity and impregnation time are presented. Compression tests were conducted and strain-stress-curves were recorded and analyzed. In addition, friction factors were determined in order to characterize the lubrication behavior. With the optimized parameters significantly higher strains and lower friction factors as compared to dry forming could be achieved.