METHOD FOR MANUFACTURING RARE EARTH ALLOY PIECE

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PROBLEM TO BE SOLVED : To provide a method for manufacturing a rare earth alloy piece capable of restraining variation of a crystal structure generated on the alloy piece obtained by consumption and change of a surface property of a quenched roll.SOLUTION : An R-T-B-based molten alloy metal is prepared by heating a raw material, and when casting an ingot by solidifying the molten alloy metal by supplying it to a quenching roll, temperature of the molten alloy metal is adjusted according to arithmetic mean roughness Ra and/or average intervals Sm of unevenness on the surface of the quenching roll, and an interval between R-rich phases on the crystal structure of the obtained alloy piece is controlled at a target value. When adjusting the temperature of the molten alloy metal according to the arithmetic mean roughness Ra and/or the average intervals Sm of unevenness, it is desirable to adjust the temperature of the molten alloy metal on the basis of the expression (1) : Δt=-7×(|ΔRa|×|ΔSm|)/α, wherein Δt is an amount of adjustment of temperature (°C) of the molten alloy metal, ΔRa is an amount of variation (μm) of the arithmetic mean roughness Ra, ΔSm is an amount of variation (μm) of the average intervals Sm of unevenness, and α is a correlation coefficient.