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Cr-containing austenite alloy pipe and production method for same

A manufacturing method and technology of alloy pipes, applied in the direction of manufacturing tools, pipes, rigid pipes, etc., can solve problems such as period extension and economic loss

Active Publication Date: 2013-05-01
NIPPON STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, if the amount of elution of Ni increases, regular inspection cannot be started until the amount of emitted radiation is reduced to an appropriate value, and the period of regular inspection is prolonged, resulting in economic loss.

Method used

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  • Cr-containing austenite alloy pipe and production method for same
  • Cr-containing austenite alloy pipe and production method for same
  • Cr-containing austenite alloy pipe and production method for same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0118] The blank pipe used for the experiment was manufactured by the following manufacturing method. First, alloys with chemical compositions shown in Table 1 were melted and cast to obtain steel ingots. After hot forging this steel ingot into a billet, it is formed into a pipe by a hot extrusion pipe-making method. The thus-obtained tube was cold-rolled using a cold pilger mill so that the outer diameter would be 25.0 mm and the wall thickness would be 1.65 mm. Next, the cold-rolled tube was annealed in a hydrogen atmosphere at 1100°C, and then finished by cold drawing to a product size of 19.0 mm in outer diameter, 1.0 mm in thickness, and 20,000 mm in length (reduction of area = 53%) the tube. Then, after cutting to a necessary length, the inner and outer surfaces of each tube were washed with an alkaline degreasing solution and flushing water, and the inner surface was further washed with acetone.

[0119] [Table 1]

[0120] Table 1

[0121]

[0122] While supplyi...

Embodiment 2

[0131] Next, as the influence of parameters, Cr-containing austenitic alloy pipes with different pipe diameters and pipe lengths were produced, and a chromium oxide film was formed under the conditions shown in Table 3 by the same method as in Example 1. The results are shown in Table 3.

[0132] [table 3]

[0133]

[0134] It can be seen from Table 3 that if the heat treatment conditions specified in the present invention are satisfied, the average film thickness of the obtained chromium oxide film is in the range of 0.05-1.5 μm, and the film thickness distribution also falls within the specified range. A Cr-containing austenitic alloy tube having a Cr oxide film having an appropriate film thickness range and distribution can be produced within the range of the tube inner diameter of 10 to 30 mm. Furthermore, regarding the influence of the tube length, by properly adjusting the water vapor concentration and the flow rate of the atmospheric gas, even a long tube of 30 m ca...

Embodiment 3

[0136] An alloy tube (tube length: 20 m, tube diameter: 17 mm) having the composition shown in Table 4 was oxidized with steam to form a chromium oxide coating. The conditions for film formation were as follows in Experiment No. 5: the hydrogen gas containing 3960 ppm water vapor was passed through the atmosphere gas at a flow rate of 12 L / min, the heat treatment temperature was 1100° C. and the treatment time was 5 minutes. Table 5 shows the measurement results of the film thickness and C concentration of the treated samples.

[0137] [Table 4]

[0138] Table 4

[0139]

[0140] [table 5]

[0141] table 5

[0142]

[0143] ** represents the average concentration of C in the range of 5 to 10 μm deep from the surface layer on the inner surface side of the tube.

[0144] Compared with Alloy A used in Examples 1 to 3, Alloys B, C, and D obtained substantially equivalent results in both thickness and distribution of coating films. In addition, it was confirmed that the ...

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Abstract

Provided is a Cr-containing austenite alloy pipe with a chrome oxide coating film that is 0.05-1.5 [mu]m thick and has the relationship shown in formula (i) formed on an inside surface thereof, wherein the C average concentration within a depth of 5-10 [mu]m from a surface layer part on the inside surface side of the pipe is less than the C concentration of the starting material. 0.4<=delta1 / delta2<=2.5(i), wherein delta1 and delta2 are the chrome oxide coating material thicknesses ([mu]m) at each end of the pipe.

Description

technical field [0001] The present invention relates to a Cr-containing austenitic alloy pipe with little Ni elution even when used in a high-temperature water environment for a long period of time, and a manufacturing method thereof, and particularly to a Cr-containing austenitic alloy pipe suitable for applications such as parts for nuclear power plants and the like. its method of manufacture. Background technique [0002] Cr-containing austenitic alloy pipes are used for various parts due to their excellent mechanical properties. In particular, parts of atomic reactors are exposed to high-temperature water, so Cr-containing austenitic alloy tubes having excellent corrosion resistance are used. For example, a 60%Ni-30%Cr-10%Fe alloy is used for steam generator components of a pressurized water reactor (PWR). [0003] These parts can be used for several years to several decades in a high-temperature water environment of about 300° C., which is a boiler water environment o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/18C22C19/05C22C38/00C22C38/58G21D1/00
CPCC23C8/18C22F1/10G21F9/28C22C19/05C22F1/00C22C38/04C21D8/10C22C19/058C22C38/42C21D6/002C22C38/02G21D1/006C21D9/08C22C38/58F16L9/02C22C38/001Y02E30/40Y02E30/30
Inventor 正木康浩田坂诚均神崎学上平明弘木野村庄司
Owner NIPPON STEEL CORP
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