NOVEL HIGHLY SINTERABLE HIGH SPEED STEEL POWDERS: COMPUTER AIDED DESIGN, SINTERING BEHAVIOUR AND MICROSTRUCTURAL EVOLUTION

摘要

Novel highly sinterable High Speed Steel powders fulfilling the requirements for robust processinghave been developed by computer aided alloy design. Previous results obtained with an experimentalpowder grade illustrate that the adequate selection of the possible constituent phases in the calculationof multicomponent phase diagrams is a key factor for success in the computer-aided alloy design ofhighly sinterable high speed steel compositions. The presence of the desired carbides after sinteringhas been promoted through the appropriate selection of the alloying elements. The comparisonbetween the predicted (≈1150 °C) and experimentally measured Optimum Sintering Temperatures ofthe new powder grades sintered under a dynamic 90N_2+9H_2+1CH_4 atmosphere together with the finalmicrostructure are also presented. On the other hand, the expected sintering windows exceed 10 °Cand the sensitivity to small compositional changes has been minimised guaranteeing an exceptionalreproducibility under industrial processing conditions.