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Method for producing high-strength cr-ni alloy seamless pipe

A manufacturing method and high-strength technology are applied in the manufacturing field of high-strength Cr-Ni alloy seamless pipes, which can solve problems such as insufficient research and achieve the effects of excellent hot workability and stress corrosion cracking resistance.

Active Publication Date: 2012-03-07
NIPPON STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, studies on obtaining higher strength Cr-Ni alloy seamless pipes having not only excellent hot workability but also excellent stress corrosion cracking resistance are insufficient.

Method used

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  • Method for producing high-strength cr-ni alloy seamless pipe
  • Method for producing high-strength cr-ni alloy seamless pipe

Examples

Experimental program
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Effect test

Embodiment 1

[0096] In Table 1, the chemical composition (mass %) of the example (test No. 1-23) of this invention and a comparative example (test No.A-J) is shown. The alloy of the example of the present invention was melted and ingot-cast using a vacuum induction electric melting furnace, and cast into a 30 kg ingot. This ingot was hot forged to form a billet with an outer diameter of 100 mm. The billet heated at 1240°C and 1260°C was pierced and rolled by a small inclined piercing and rolling device, and the pipe was made into a pipe with an outer diameter of 116mm and a thickness of 20mm.

[0097]

[0098] The rear end of the pierced and rolled seamless billet was cut into circular pieces at a position of 50 mm in the longitudinal direction, and the presence or absence of lamination of the billet was checked. It was judged as (◯) if spalling did not occur, and as (×) if it occurred.

[0099] In addition, the seamless steel pipe obtained by heating at 1240° C., piercing and rolling...

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Abstract

A method for producing a high-strength Cr-Ni alloy seamless pipe is provided. The high-strength Cr-Ni alloy seamless pipe is excellent in hot workability and stress corrosion cracking resistance, does not occur a lamination during piercing-rolling, and is characterized by: using an alloy billet to carry out a hot working to make a seamless material pipe on the basis of a cross roll piercing process; subjecting a solution treatment; and carrying out a cold working; wherein, the alloy billet has a chemical composition comprising, by mass%, of C: 0.05% or less, Si: 1.0% or less, Mn: less than 3.0%, P: 0.005% or less, S: 0.005% or less, Cu: 0.01 to 4.0%, Ni: 25% or more and less than 35%, Cr: 20 to 30%, Mo: 0.01% or more and less than 4.0%, N: 0.10 to 0.30%, Al: 0.03 to 0.30%, O (oxygen): 0.01% or less, REM (rare earth metal): 0.01 to 0.20%, and the balance being Fe and impurities, and satisfying the following formula (1); wherein, P, N and REM in formula (1) represent the contents (mass%) of P, N and REM, respectively. The Cr-Ni alloy seamless pipe may further contain one or more of W, Ti, Nb, Zr, V, Ca and Mg, and in formula (1) N*P / REM<=0.10.

Description

technical field [0001] The present invention relates to a method for manufacturing a high-strength Cr-Ni alloy seamless pipe excellent in hot workability and stress corrosion cracking resistance. Background technique [0002] As the price of crude oil has increased in recent years, the development of oil and gas wells at higher depths and in severe corrosive environments has continued. With the extraction of oil and natural gas under such harsh environments, oil well pipes used for the extraction are also required to have high strength and excellent corrosion resistance and stress corrosion cracking resistance. [0003] Since the demand for oil and natural gas has increased in recent years, oil wells and gas wells for exploiting them tend to be deeper. As wells become deeper, materials used in such wells are required to further increase in strength while maintaining corrosion resistance against carbon dioxide, hydrogen sulfide, and chloride ions. [0004] There are Cr—Ni a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/10C22C38/00C22C38/58
CPCC21D6/004C21D8/10C22C1/11
Inventor 乙咩阳平五十岚正晃冈田浩一近藤邦夫相良雅之下田一宗
Owner NIPPON STEEL CORP
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