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US 10,441,982 B2Granted
Plug for rolling of seamless steel pipe, method for manufacturing the same and method for manufacturing seamless steel pipe using the same
AssigneeJfe Steel Corporation
InventorsTakaaki Iguchi, Tatsuro Katsumura, Hideto Kimura
Life of this patent
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Abstract
A plug for rolling of a seamless steel pipe, the plug having an oxide layer composed of a cobalt-base oxide on a surface of a coating layer formed by coating a surface of a base metal with cobalt or a cobalt-base alloy, a method for manufacturing the plug and a method for manufacturing a seamless steel pipe using the plug.
Claims14
A plug for rolling of a seamless steel pipe, the plug comprising:
- a base metal;
- a coating layer formed on the base metal by coating a surface of the base metal with pure cobalt comprising 99 mass % or more of cobalt and a balance being inevitable impurities or a cobalt-nickel alloy, the cobalt-nickel alloy containing 0.3 mass % or more and 30 mass % or less of Ni;
- and
- an oxide layer including a cobalt-base oxide formed on a surface of the coating layer,
- wherein an average thickness of the oxide layer is in the range of 10 μm to 40 μm.
2 more elements
A method for manufacturing a plug for rolling of a seamless steel pipe, the method comprising:
- coating a surface of a metallic plug with a film including pure cobalt comprising 99 mass % or more of cobalt and a balance being inevitable impurities or a cobalt-nickel alloy having a thickness in the range of 0.1 mm to 2 mm, the cobalt-nickel alloy containing 0.3 mass % or more and 30 mass % or less of Ni;
- and
- after the coating step, performing a heat treatment in atmospheric air at a temperature of 300° C. to 1000° C. in order to form an oxide layer including a cobalt-base oxide, the oxide layer having an average thickness in the range of 10 μm to 40 μm.
A plug for rolling of a seamless steel pipe, the plug comprising:
- a base metal;
- a coating layer formed on the base metal by coating a surface of the base metal with pure cobalt comprising 99 mass % or more of cobalt and a balance being inevitable impurities;
- and
- an oxide layer including a cobalt-base oxide formed on a surface of the coating layer,
- wherein an average thickness of the oxide layer is in the range of 10 μm to 40 μm.
2 more elements
Dependencies are inferred from the claim text.