Hearth roll for continuous annealing furnace

Patent metadata

Field	Value
Publication number	US-12312646-B2
Application number	US-202017773629-A
Country	US
Kind code	B2
Filing date	Dec 22, 2020
Priority date	Dec 23, 2019
Publication date	May 27, 2025
Grant date	May 27, 2025

Abstract

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 or two types of a first double oxide consisting of Al and a rare earth element and a second double oxide consisting of a transition metal and a rare earth element, and when the main components are 100 mass %, a content of the Co-based alloy is 25 mass % or more and 50 mass % or less, a content of the carbide is 5 mass % or more and 30 mass % or less, and a content of the double oxide is 20 mass % or more and 45 mass % or less.

First claim

The invention claimed is:

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 a first double oxide consisting of Al and a rare earth element, and 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 total molar quantity of Al and transition metals not constituting the carbide in the main components, and D denotes a molar quantity of rare earth element included in the main components.

2. The hearth roll for the continuous annealing furnace according to claim 1 , wherein
the Co-based alloy is selected from the group consisting of a CoCrAlY-based heat resistant alloy, a CoNiCrAlY-based heat resistant alloy, and a CoCrMoNi-based heat resistant alloy.

3. The hearth roll for the continuous annealing furnace according to claim 1 , wherein
the carbide is selected from the group consisting of a chromium carbide and a molybdenum carbide.

4. The hearth roll for the continuous annealing furnace according to claim 1 , wherein
the first double oxide is selected from the group consisting of LaAlO 3 , NdAlO 3 , YAlO 3 , and Y 3 Al 5 O 12 .

5. The hearth roll for the continuous annealing furnace according to claim 1 , wherein the second double oxide is selected from the group consisting of LaCrO 3 , NdCrO 3 , and YCrO 3 .

Assignees

• Nippon Steel Corp
• Nippon Steel Hardfacing Corp

Inventors

• Kurisu Yasushi
• Li Yu
• Yagyu Koji

Classifications

• C21D9/56

  Continuous furnaces for strip or wire · CPC title

• C21D9/563

  Rolls; Drums; Roll arrangements · CPC title

• C23C4/14

  for coating elongate material · CPC title

• C23C4/11

  Oxides · CPC title

• C23C4/073

  containing MCrAl or MCrAlY alloys, where M is nickel, cobalt or iron, with or without non-metal elements · CPC title