	US 12,473,606 B2
	Hearth roll for continuous annealing furnace
Yasushi Kurisu, Tokyo (JP); Yu Li, Tokyo (JP); and Koji Yagyu, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP); and NIPPON STEEL HARDFACING CORPORATION, Tokyo (JP)
Filed by NIPPON STEEL CORPORATION, Tokyo (JP); and NIPPON STEEL HARDFACING CORPORATION, Tokyo (JP)
Filed on Apr. 29, 2025, as Appl. No. 19/192,995.
Application 19/192,995 is a division of application No. 17/773,629, granted, now 12,312,646, previously published as PCT/JP2020/047905, filed on Dec. 22, 2020.
Claims priority of application No. 2019-231246 (JP), filed on Dec. 23, 2019.
Prior Publication US 2025/0257417 A1, Aug. 14, 2025
Int. Cl. C21D 9/00 (2006.01); C21D 9/56 (2006.01); C23C 4/073 (2016.01); C23C 4/11 (2016.01); C23C 4/14 (2016.01)

CPC C21D 9/0012 (2013.01) [C21D 9/56 (2013.01); C21D 9/563 (2013.01); C23C 4/073 (2016.01); C23C 4/11 (2016.01); C23C 4/14 (2013.01)]

4 Claims

1. A hearth roll for a continuous annealing furnace, the hearth roll comprising a thermal spray coating on a surface of the hearth roll, wherein

the thermal spray coating comprises main components consisting of a Co-based alloy, a carbide of a transition metal, and a double oxide, and

impurities,

the double oxide consists of one type consisting of a second double oxide consisting of a transition metal and a rare earth element,

a content of the Co-based alloy is 25 mass % or more and 50 mass % or less of the main components, a content of the carbide is 5 mass % or more and 30 mass % or less of the main components, and a content of the double oxide is 20 mass % or more and 45 mass % or less of the main components,

2/3≤(A/B)≤4 is satisfied, where A and B respectively denote a molar quantity of the transition metals and a molar quantity of carbon in the carbide, and

1≤(C/D)≤4 is satisfied, where C denotes a molar quantity of the transition metals not constituting the carbide in the main components, and D denotes a molar quantity of the rare earth element included in the main components.