Fine (4μm) and coarse (30μm) water atomized high speed steel powders were prepared as slips and compacted by high-speed centrifugal compaction process (HCP).
The HCP green compacts of the both fine and coarse powders can be sintered to almost full density at 1448K to 1498K without any pressure assistance during sintering. Their sintering behavior, however, were quite different. While the compact of coarse powder needed to form a liquid phase to densify and resulted in a coarse microstructure, that of fine powders densified in solid phase so that fine microstructures were obtained. A homogeneous packing of fine several micron powder by the HCP was essential to solid state sintering of high speed steel. The HCP compact of fine powders showed a comparable hardness and strength to wrought materials.