Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Sumitomo Metal Industries, Inc.

Kiyoko Takeda

Masaaki Terunuma

Hiroyuki Anada

Tetsuo Yokoyama

Hirokazu Okada

Yoshitaka Nishiyama

Takahiro Osuki

Haruhiko Kajimura

Osamu Miyahara

Yasuhiro Masaki

Yoshio Tarutani

Mitsuo Miyahara

Shoji Kinomura

Shigeki Azuma

Shunichi Otsuka

Masatoshi Toyoda

Takamitsu Takagi

Junichi Higuchi

Yasushi Matsuda

Provided is an alloy having a high strength and a low thermal expansion coefficient. The alloy according to the present disclosure includes a chemical composition containing, in mass %: C: 0.10% or less, Si: 0.50% or less, Mn: 0.15 to 0.60%, P: 0.015% or less, 5: 0.0030% or less, Ni: 30.0 to 40.0%, Cr: 0.50% or less, Mo: 0.50% or less, Co: 0.250% or less, Al: 0.0150% or less, Ca: 0.0050% or less, Mg: 0.0300% or less, N: 0.0100% or less, O: 0.0300% or less, Pb: 0.0040% or less, and Zn: 0.020% or less, one or more elements selected from the group consisting of Nb: 0 to less than 0.145%, Ti: 0 to less than 0.145%, and. V: 0 to less than 0.145%: 0.015 to less than 0.145% in total, with the balance being Fe and impurities, and satisfying Formula (1).(Nb+3×Ti+V)/(C+N)≤6.00  (1)

Alloy

The production method of a Ni-based alloy according to the present embodiment includes: a casting step of casting a liquid alloy which is a raw material of the Ni-based alloy to produce a Ni-based alloy starting material; and a segregation reducing step of performing, on the Ni-based alloy starting material produced by the casting step, heat treatment, or the heat treatment and complex treatment including hot working and heat treatment after the hot working, to satisfy Formula (1):

Method for producing ni-based alloy and ni-based alloy

An Ni-based alloy pipe for nuclear power has a chemical composition consisting of, in mass percent: C: 0.015 to 0.030%, Si: 0.10 to 0.50%, Mn: 0.10 to 0.50%, P: 0.040% or less, S: 0.015% or less, Cu: 0.01 to 0.20%, Ni: 50.0 to 65.0%, Cr: 19.0 to 35.0%, Mo: 0 to 0.40%, Co: 0.040% or less, Al: 0.30% or less, N: 0.010 to 0.080%, Ti: 0.020 to 0.180%, Zr: 0.010% or less, and Nb: 0.060% or less, the balance: Fe and impurities, and satisfying [(N&#x2212;Ti&#xd7;14/48)&#xd7;d&#x2265;4000] in relation to an average grain diameter, wherein a standard deviation of grain diameters is 20 &#x3bc;m or less, and a hardness of insides of grains is 180 HV or more.

Ni-based alloy pipe for nuclear power

Provided is a nickel material having excellent corrosion resistance and high strength, and a method for manufacturing the nickel material. A nickel material has a chemical composition consisting of, in mass %, C: 0.001 to 0.20%, Si: 0.15% or less, Mn: 0.50% or less, P: 0.030% or less, S: 0.010% or less, Cu: 0.10% or less, Mg: 0.15% or less, Ti: 0.005 to 1.0%, Nb: 0.040 to 1.0%, Fe: 0.40% or less, sol. Al: 0.01 to 0.10%, an N: 0.0010 to 0.080%, with the balance being Ni and impurities, and satisfying Formula (1) and Formula (2).0.030&#x2264;( 45/48)Ti+( 5/93)Nb&#x2212;( 1/14)N&#x3c;0.25&#x2003;&#x2003;(1)0.030&#x3c;( 3/48)Ti+( 88/93)Nb&#x2212;( 1/12)C&#x2003;&#x2003;(2) A content (mass %) of a corresponding element is substituted for each element symbol in Formula (1) and Formula (2).

Nickel material and method for manufacturing nickel material

An object of the present invention is to provide an Ni-based alloy pipe or tube for nuclear power with reduced rate of SCC crack propagation. The Ni-based alloy pipe or tube for nuclear power according to the present invention is an Ni-based alloy pipe or tube having a wall thickness of 15 to 55 mm, having a chemical composition of, in mass %: 0.010 to 0.025% C; 0.10 to 0.50% Si; 0.01 to 0.50% Mn; up to 0.030% P; up to 0.002% S; 52.5 to 65.0% Ni; 20.0 to 35.0% Cr; 0.03 to 0.30% Mo; up to 0.018% Co; up to 0.015% Sn; 0.005 to 0.050% N; 0 to 0.300% Ti; 0 to 0.200% Nb; 0 to 0.300% Ta; 0% or more and less than 0.03% Zr; and the balance being Fe and impurities, wherein the Ni-based alloy pipe or tube has a microstructure being an austenite single phase, and the chemical composition satisfies the following equation, Eq. (1):&#x2212;0.0020&#x2264;[N]/14&#x2212;{[Ti]/47.9+[Nb]/92.9+[Ta]/180.9+[Zr]/91.2}&#x2264;0.0015&#x2003;&#x2003;Eq. (1).For the element symbols in Eq. (1), the contents of the corresponding elements in mass % are substituted.

Ni-based alloy pipe or tube for nuclear power

There is provided a welding material used for welding of SUS310 stainless steel base metal that contains at least one of Nb and V and is excellent in intergranular corrosion resistance, the chemical composition of the welding material consisting, by mass percent, of C: 0.02% or less, Si: 2% or less, Mn: 2% or less, Cr: 26 to 50%, N: 0.15% or less, P: 0.02% or less, S: 0.002% or less, and Ni: a content percentage satisfying [5&#x2264;Ni&#x2264;Cr&#x2212;14], and the balance of Fe and impurities. Also, there is provided a welding joint of an austenitic stainless steel, which consists of the base metal and a weld metal formed by using the welding material.

Welding material and welding joint

A nickel material, which comprises by mass percent, C: 0.003 to 0.20% and one or more elements selected from Ti, Nb, V and Ta: a total content less than 1.0%, the contents of these elements satisfying the relationship specified by the formula of '(12/48) Ti+(12/93) Nb+(12/51) V+(12/181) Ta&#x2014;C&#x2267;0', with the balance being Ni and impurities, does not deteriorate in the mechanical properties and corrosion resistance even when it is used at a high temperature for a long time and/or it is affected by the heat affect on the occasion of welding. Therefore, it can be suitably used as a member for use in various chemical plants including facilities for producing caustic soda, vinyl chloride and so on. Each element symbol in the above formula represents the content by mass percent of the element concerned.

Nickel material for chemical plant

An austenitic stainless steel with minimized deformation by heating and cooling treatment after cold working, which consists of, % by mass, C: 0.03% or less, Si: 2 to 4%, Mn: 0.1 to 2%, P: 0.03% or less, S: 0.03% or less, Ni: 9 to 15%, Cr: 15 to 20%, N: 0.02 to 0.2%, Nb: 0.03% or less, each of Mo and Cu or a total of Mo and Cu: 0.2 to 4%, and the balance Fe and impurities, and satisfies the following formulas (1) and (2). This steel can also have good weldability when the following formula (3) is also satisfied in addition to the formulas (1) and (2);16.9+6.9Ni+12.5Cu&#x2212;1.3Cr+3.2Mn+9.3Mo&#x2212;205C&#x2212;38.5N&#x2212;6.5Si&#x2212;120Nb&#x2267;40&#x2003;&#x2003;(1)450&#x2212;440(C+N)&#x2212;12.2Si&#x2212;9.5Mn&#x2212;13.5Cr&#x2212;20(Cu+Ni)&#x2212;18.5Mo&#x2266;&#x2212;90&#x2003;&#x2003;(2)8.2+30(C+N)+0.5Mn+Ni&#x2212;1.1(1.5Si+Cr+Mo)+2.5Nb&#x2266;&#x2212;0.8&#x2003;&#x2003;(3)

Austenitic stainless steel

A stainless steel having excellent corrosion resistance to ozone added water, such as ozone added ultrapure water used in semiconductor manufacturing processes and the like, as well as a manufacturing method. The stainless steel comprises a base metal and an oxide film formed on the surface of the base metal, the base metal being a stainless steel which contains 12 to 30% of Cr, 0 to 35% of Ni, and 1 to 6% of Al and Si while the contents of the other alloying elements are limited to as low a level as possible, the oxide film mainly comprising Al oxide or a Si oxide or both. The oxide film may be formed on the base metal surface through the dry oxidation process or the wet oxidation process. In the stainless steel, metallic ions are rarely dissolved from the base metal into the ozone added water. Also, since the contents of alloying elements, other than Cr, Ni, Al, Si, and like necessary elements, are limited to a low level, the stainless steel exhibits excellent corrosion resistance and reduced particle emission.

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Nishinomiya, Japan

Kiyoko Takeda