PROCESS FOR PRODUCING R-T-B-BASED RARE EARTH MAGNET POWDER, R-T-B-BASED RARE EARTH MAGNET POWDER,

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An object of the present invention is to provide a process for producing R-T-B-based rare earth magnet powder having excellent coercive force and high remanent flux density. The present invention relates to a process for producing R-T-B-based rare earth magnet powder by HDDR treatment, in which a raw material alloy for the R-T-B-based rare earth magnet powder comprises R (wherein R represents at least one rare earth element including Y), T (wherein T represents Fe, or Fe and Co) and B (wherein B represents boron), and has a composition comprising R in an amount of not less than 12.0 atom% and not more than 17.0 atom%, and B in an amount of not less than 4.5 atom% and not more than 7.5 atom%; the HDDR treatment comprises a DR step comprising a preliminary evacuation step and a complete evacuation step; and a rate of pressure reduction caused by evacuation in the preliminary evacuation step is not less than 1 kPa/min and not more than 30 kPa/min.