Influence of compaction pressure on the anisotropy of sintering shrinkage of ring-shaped sponge and atomized iron parts

The influence of green density and geometry on the anisotropy of sintering shrinkage of large rings (100 mm external diameter, 42 mm internal diameter) produced with water atomized iron powder has been studied in previous work. In this work water atomized iron powder and sponge iron powder have been used to produce small ring-shaped parts (40 mm external diameter, 20 mm internal diameter, three different heights), compacted up to five different compaction pressures and sintered at 1120 °C in low C potential endogas atmosphere (30 mins). Diameters and height of green and sintered specimens have been measured by CMM, and dimensional changes, as well as change in volume, have been derived. Data have been compared with previous sampling, and the influence of the several variables on the anisotropic dimensional change has been highlighted, also evaluating the trend of the anisotropy coefficient K.