CPC C22C 45/02 (2013.01) [B22F 1/05 (2022.01); B22F 1/08 (2022.01); B22F 9/082 (2013.01); B22F 2009/088 (2013.01); B22F 2009/0828 (2013.01); B22F 2301/35 (2013.01)] | 8 Claims |
1. A production method for water-atomized metal powder, comprising:
spraying primary cooling water that is to impact on a vertically falling molten metal stream to divide the molten metal stream into metal powder and to cool the metal powder, thereby producing water-atomized metal powder having a total content of iron-group components (Fe, Ni, Co) in atomic percent of 82.9 at % or more and 86.0 at % or less, an amorphous proportion of 90% or more, and an apparent density of 3.0 g/cm3 or more, wherein:
in a region in which an average temperature of the molten metal stream is higher than a melting point by 100° C. or more, the primary cooling water is sprayed from a plurality of directions at a convergence angle of 10° to 25°, the convergence angle being an angle between an impact direction on the molten metal stream of the primary cooling water from one direction among a plurality of the directions and an impact direction on the molten metal stream of the primary cooling water from any other direction; and
in a region in which 0.0004 seconds or more have passed after an impact of the primary cooling water and an average temperature of the metal powder is a melting point or higher and (the melting point+50° C.) or lower, secondary cooling water is sprayed on the metal powder under conditions of an impact pressure of 10 MPa or more.
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