Reclamation of metal cutting brass chips using powder metallurgy

The development of technology for producing powder from suitably separated and cleaned chips, grading, blending various sizes of powder, the addition of lubricants, compaction using a double action die, and the sintering of compacts in a muffle furnace under conditions which prevent the loss of zinc in either liquid or vapour form is presented. The geometrical and morphological features of the cylindrical specimens are investigated using metallography, optical microscopy, SEM, and roughness measurement. The physical and mechanical characteristics of both green compacts and sintered specimens are ascertained through a series of standard tests for density ratio, hardness, compression, shear, and impact resistance. On the basis of these test results the optimum conditions required for complete processing are put forward to obtain a sintered specimen of quality from the chips available, from a technological and economic point of view. A cost analysis establishes the viability of the process compared to the PM processing of commercial brass powder under similar conditions. PM/0533. © 1991 Maney Publishing.