PLUG FOR ROLLING OF SEAMLESS STEEL PIPE, METHOD FOR MANUFACTURING THE SAME AND METHOD FOR MANUFACTURING SEAMLESS STEEL PIPE USING THE SAME
First Claim
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1. 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 cobalt or a cobalt-base alloy; and
an oxide layer including a cobalt-base oxide formed on a surface of the coating layer.
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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.
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Citations
11 Claims
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1. A plug for rolling of a seamless steel pipe, the plug comprising:
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a base metal; a coating layer formed on the base metal by coating a surface of the base metal cobalt or a cobalt-base alloy; and an oxide layer including a cobalt-base oxide formed on a surface of the coating layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for manufacturing a plug for rolling of a seamless steel pipe, the method comprising:
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coating a surface of a metallic plug with a film including cobalt or a cobalt-base alloy having a thickness in the range of 0.1 mm to 2 mm; and after the coating step, performing 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 μ
m to 40 μ
m. - View Dependent Claims (10, 11)
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Specification