Nippon Steel Sumitomo Metal Corporation

Sumitomo Metal Industries, Inc.

Manabu Kanzaki

Yasuhiro Masaki

Osamu Miyahara

Shoji Kinomura

Akihiro Uehira

Yasuyoshi Hidaka

Mitsuharu Yonemura

Yumi Momozono

Noriaki Hirohata

Masanari Kimoto

Masahito Tasaka

Hiroyuki Anada

Toshihiro Imoto

Kazuyuki Kitamura

A Ni-based alloy tube includes a base metal having a chemical composition consisting, by mass percent, of C: 0.15% or less, Si: 1.0% or less, Mn: 2.0% or less, P: 0.030% or less, S: 0.030% or less, Cr: 10.0 to 40.0%, Ni: 50.0 to 80.0%, Ti: 0.50% or less, Cu: 0.60% or less, Al: 0.20% or less, N: 0.20% or less, and the balance: Fe and impurities; and a low Cr content complex oxide film having a thickness of 25 nm or smaller at least on an inner surface of the base metal, wherein contents of Al, Ni, Si, Ti, and Cr in the film satisfy [at % Al/at % Cr&#x2264;2.00], [at % Ni/at % Cr&#x2264;1.40], and [(at % Si+at % Ti)/at % Cr&#x2265;0.10].

Ni-based alloy tube

An austenitic alloy tube subjected to a cold working and an annealing heat treatment contains C: 0.01% to 0.15%, Cr: 10.0% to 40.0%, Ni: 8.0% to 80.0%, in mass %, and has a metallographic structure satisfying the following Expressions (i) to (iii).1&#x2003;&#x2003;(i)&#x2003;&#x2003;(ii)1=0.28&#xd7;(/(0.35))&#x2003;&#x2003;(iii)

Austenitic alloy tube

There is provided a Cr-containing austenitic alloy having a chromium oxide film with a thickness of 5 nm or larger on the surface, wherein the content of Mn in a base metal is, by mass percent, less than 0.1%. The chemical composition of the base metal desirably consists of, by mass percent, C: 0.15% or less, Si: 1.00% or less, Mn: less than 0.1%, P: 0.030% or less, S: 0.030% or less, Cr: 10.0 to 40.0%, Ni: 8.0 to 80.0%, Ti: 0.5% or less, Cu: 0.6% or less, Al: 0.5% or less, and N: 0.20% or less, the balance being Fe and impurities.

Cr-containing austenitic alloy and method for producing the same

There is provided a chromium-containing austenitic alloy wherein at least one surface of the surfaces of the alloy has a continuous chromium oxide film with a thickness of 5 nm or more and less than 50 nm. A maximum current density determined by a critical passivation current density method is 0.1 &#x3bc;A/cmor less when the chromium oxide film is continuous. A chemical composition of a base metal preferably consists of, by mass percent, C: 0.15% or less, Si: 1.00% or less, Mn: 2.0% or less, P: 0.030% or less, S: 0.030% or less, Cr: 10.0 to 40.0%, Ni: 8.0 to 80.0%, Ti: 0.5% or less, Cu: 0.6% or less, Al: 0.5% or less, and N: 0.20% or less, the balance being Fe and impurities.

Chromium-containing austenitic alloy

There is provided a Cr-containing austenitic alloy tube, wherein a chromium oxide film with a thickness of 0.05 to 1.5 &#x3bc;m having the relationship defined by Formula (i) is formed on the inner surface of the tube, wherein the average concentration of C in the depth range of 5 to 10 &#x3bc;m from the inner surface is lower than the concentration of C in a base metal;0.4&#x2266;&#x3b4;1/&#x3b4;2&#x2266;2.5&#x2003;&#x2003;(i)wherein &#x3b4;1 and &#x3b4;2 are thicknesses (&#x3bc;m) of the chromium oxide film at both ends of tube, respectively.

Cr-containing austenitic alloy tube and method for producing the same

A Ni&#x2014;Cr alloy tube demonstrating an excellent corrosion resistance in a high temperature water environment can be provided,

Ni-Cr alloy material

A nickel alloy having an excellent corrosion resistance (hereinafter referred to as 'nickel alloy') used for pipes, structural materials and structural members, such as bolts or the like, in a nuclear power plant or in a chemical plant, and a manufacturing method for the same are provided. In the nickel alloy according to the present invention, an excellent corrosion resistance, in particular an excellent resistance against the IGSCC, is obtained by specifying the low angle boundary rate of 4% or more in the grain boundaries, along with the restriction of the chemical composition in the alloy, thereby making it possible to provide a nickel alloy which is most suitably used for pipes, structural materials and structural members, such as bolts or the like. Accordingly, the nickel alloy according to the present invention is widely applicable to structural members used in a nuclear station or in a chemical plant.

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Tokyo, Japan

Manabu Kanzaki