US 11,795,532 B2
Production method for water-atomized metal powder
Makoto Nakaseko, Tokyo (JP); Shigeru Unami, Tokyo (JP); Akio Kobayashi, Tokyo (JP); and Takuya Takashita, Tokyo (JP)
Assigned to JFE Steel Corporation, Tokyo (JP)
Appl. No. 17/282,448
Filed by JFE Steel Corporation, Tokyo (JP)
PCT Filed Oct. 10, 2019, PCT No. PCT/JP2019/040050
§ 371(c)(1), (2) Date Apr. 2, 2021,
PCT Pub. No. WO2020/075815, PCT Pub. Date Apr. 16, 2020.
Claims priority of application No. 2018-192258 (JP), filed on Oct. 11, 2018.
Prior Publication US 2021/0379658 A1, Dec. 9, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. B22F 9/08 (2006.01); C22C 45/02 (2006.01); B22F 1/08 (2022.01); B22F 1/05 (2022.01)
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
OG exemplary drawing
 
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.