From powder to car parts.
Parts produced using powder metallurgy are becoming increasingly important, particularly in the automobile industry. For the production of sintered parts, metal powders are mixed with small quantities of additives such as waxes and graphite. These powder mixtures are then pressed unter high pressure into so-called green compacts.
As part of this process, graphite ensures reduced wear of the press die and provides internal lubrication within the powder mixture. As a result, graphite makes maximum compression possible. In the sintering process, in which the green compacts are heated to slightly below melting point, the material is then compressed further. Moreover, fine graphite goes into solution in the metal and in doing so increases the mechanical strength of the workpiece.
Self-lubrication - smoothly does it.
Special powder mixtures exist for self-lubricating sintered parts. These special mixtures contain coarser graphite that only goes into solution to a small extent during the sintering process. The graphite particles are largely incorporated into the matrix of the workpiece in intact condition and are gradually exposed during the useful life of the part, which enables the graphite to develop its lubricating effect.