JP4151065B2 - Ni-base alloy with excellent resistance to stress corrosion cracking in supercritical water environment containing inorganic acid - Google Patents

Description

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表１〜６に示された結果から、本発明Ｎｉ基合金板１〜４２は、固溶化材試験片も時効材試験片も、従来Ｎｉ基合金板１および２に見られるような応力腐食割れの発生がなく、したがって耐応力腐食割れ性が優れていることが分かる。しかし、この発明から外れた成分組成を有する比較Ｎｉ基合金板１〜１１の固溶化材試験片および時効材試験片の少なくともいずれかに応力腐食割れが発生したり、著しい全面腐食が発生するなどして好ましくないことが分かる。
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【発明の効果】
上述のように、この発明のＮｉ基合金は、硫酸およびリン酸、またはリン酸およびフッ酸を含む超臨界水環境下において耐応力腐食割れ性に優れているところから長期間の使用が可能となり、ＶＸガスまたはＧＢガスの無害化処分などの環境産業上優れた効果をもたらすものである。
なお、この発明のＮｉ基合金は、上述の如く、硫酸、燐酸、フッ酸など塩素を含まない無機酸を含む超臨界水環境下で使用することが最も有効であるが、これに限定されるものではなく、塩酸、硝酸を含む超臨界水環境や塩化ナトリウム、塩化マグネシウム、塩化カルシウム等塩化物塩を含む超臨界水環境、アンモニアを含む超臨界水環境でも使用可能であり、従って、宇宙関連廃棄物、原子力関連廃棄物、電子力関連廃棄物、一般産業廃棄物の処分用の超臨界水装置材料にも適用できる。
また、この発明のＮｉ基合金を装置本体の反応チャンバーとして使用する際、外側をステンレス鋼等の強度用材料とし、内面にこの発明のＮｉ基合金をクラッドやライニングしてもよい。[0001]
[Industrial application fields]
The present invention relates to a Ni-based alloy having excellent stress corrosion cracking resistance in an inorganic acid-containing supercritical water environment, and a member for a supercritical water process reactor made of this Ni-based alloy. For supercritical water containing inorganic acids that do not contain chlorine, such as sulfuric acid, phosphoric acid, and hydrofluoric acid, generated by decomposing and oxidizing organic harmful substances used in chemical weapons such as GB (saline) gas and mustard gas The present invention relates to a Ni-based alloy having excellent stress corrosion cracking resistance and a member for a supercritical water process reactor comprising this Ni-based alloy.
[0002]
[Prior art]
Water at a temperature / pressure exceeding the critical point (specifically, water at a temperature / pressure exceeding 374 ° C./22.1 MPa) is called supercritical water, and supercritical water dissolves various substances. This supercritical water becomes a non-condensable high-density gas state, and even nonpolar or weakly polar substances (hydrocarbon compounds and gases) with extremely low solubility at room temperature are completely dissolved, and oxygen It is said that the dissolved substance can be oxidized and decomposed by adding.
[0003]
Organic harmful substances used in chemical weapons are no exception. They are completely dissolved in supercritical water, and the added dissolved oxygen and organic harmful substances used in chemical weapons react in supercritical water. By doing so, it is oxidatively decomposed into harmless substances such as sulfuric acid and phosphoric acid in addition to carbon dioxide and water. For example, sulfuric acid and phosphoric acid are generated when VX gas is oxidatively decomposed, and hydrofluoric acid and phosphoric acid are generated when GB gas is oxidatively decomposed. Therefore, in recent years, in the United States, supercritical water is used to dispose of chemical weapons using VX gas, GB (saline) gas, mustard gas, etc., and these persistent VX gas, GB (saline) Attempts have been made to decompose and oxidize organic harmful substances such as gas and mustard gas to make them harmless. If a method to decompose and oxidize organic harmful substances such as VX gas, GB (saline) gas, and mustard gas with supercritical water is established, it becomes supercritical compared to conventional incineration treatment methods. Water and oxidizers have no negative impact on the environment, and supercritical water is highly reactive, so it decomposes and oxidizes organic harmful substances such as VX gas, GB (saline) gas, and mustard gas in a short time and is harmless. In addition, since it can be decomposed in a closed system, there is no risk of environmental pollution due to emissions.
[0004]
In order to decompose and oxidize organic harmful substances such as VX gas, GB (saline) gas, mustard gas, etc. by using such supercritical water as a reaction solvent, high temperature and high pressure (400 to 650 ° C., 22 .1 to 80 MPa) in an apparatus for detoxifying organic harmful substances from an environment in which inorganic acids such as sulfuric acid, phosphoric acid, hydrofluoric acid and the like, which are produced after oxidative decomposition, coexist with oxygen in high concentrations. The material of the reaction vessel is required to have corrosion resistance under such inorganic acid-containing supercritical water.
[0005]
Therefore, as a metal material used in a reaction vessel of a process reaction apparatus using supercritical water, a Ni-based alloy known for high corrosion resistance is listed as a candidate for a process reaction vessel material of the apparatus. For example, Inconel (trade name) 625 (specified by ASTM UNS N06625), the composition of the components is, for example, Cr: 21.0%, Mo: 8.4%, Nb + Ta: 3.6% by mass. Fe: 3.8%, Co: 0.6%, Ti: 0.2%, Mn: 0.2%, the balance: Ni + inevitable impurities) and Hastelloy (trade name) C-276 (As defined in ASTM UNS N10276, the component composition is, for example, Cr: 15.5%, Mo: 16.1%, W: 3.7%, Fe: 5.7%, Co: 0.5 %, Mn: 0.5% and the balance: Ni + inevitable impurities).
Recently, there has also been a report that a Ni-based alloy having a higher Cr content is more excellent in corrosion resistance than inorganic acid-containing supercritical water, and Hastelloy (trade name) G is a Ni-based alloy having a higher Cr content. -30 (ASTM UNS N06030 (component composition is, for example, Cr: 28.7%, Mo: 5.0%, Mn: 1.1%, Fe: 14.6%, Cu: 1.8%, W: Attention has been focused on Ni-high Cr type alloys such as 2.6, containing Co: 1.87% and the balance: Ni + unavoidable impurities.
[0006]
[Problems to be solved by the invention]
These conventional Ni-based alloys are formed into a plate or a tube to produce a processed material, and the processed material is further subjected to a forming process such as rolling or bending to be finished into a reaction vessel or a pipe of a process reaction apparatus. Since the reaction vessel or piping finished in this way is produced by molding, residual internal stress and internal strain are inevitable.
However, Inconel 625 and Hastelloy C-276 among conventional Ni-based corrosion resistant alloys cause stress corrosion cracking when brought into contact with supercritical water containing inorganic acids not containing chlorine such as sulfuric acid, phosphoric acid, and hydrofluoric acid. Among these conventional Ni-based corrosion resistant alloys, if Inconel 625 or Hastelloy C-276 is used as a material for reaction vessels and piping in an apparatus for detoxifying organic harmful substances, long-term operation is difficult.
In addition, Hastelloy (trade name) G-30 has insufficient phase stability even though it has sufficient resistance to stress corrosion cracking in supercritical water containing acids such as sulfuric acid, phosphoric acid and hydrofluoric acid at the initial stage of operation. Therefore, when the phase transformation gradually proceeds at the operating temperature (400 to 650 ° C.) and a stress field such as in a high-temperature / high-pressure supercritical water environment is generated in the state where the phase transformation has progressed, stress corrosion cracking occurs. This is not suitable as a material for a process reactor used for a long time.
[0007]
[Means for solving the problems]
Therefore, the present inventors do not cause stress corrosion cracking even in an inorganic acid-containing supercritical water environment, and further, because the phase stability is excellent even when kept at a use temperature (400 to 650 ° C.) for a long time, Developed a Ni-based alloy that shows sufficient stress corrosion cracking resistance in an inorganic acid-containing supercritical water environment with the progress of transformation suppressed, and uses this Ni-based alloy for a long time in an inorganic acid-containing supercritical water environment. In order to obtain supercritical water process reactor components that can be operated for a long period of time, intensive research was conducted. as a result,
(B)% by mass (hereinafter,% indicates% by mass), Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: 0.05 to 0.5%, the balance is made of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is adjusted to 0.05% or less. The Ni-based alloy having a composition is excellent in stress corrosion cracking resistance and phase stability in an inorganic acid-containing supercritical water environment, particularly in an inorganic acid-containing supercritical water environment not containing chlorine such as sulfuric acid, phosphoric acid and hydrofluoric acid. Because of its excellent resistance, even if it is kept at a use temperature (400 to 650 ° C.) for a long time, the progress of phase transformation is suppressed and there is no stress corrosion cracking, and this Ni-based alloy is an organic harmful substance using supercritical water. When used as a reaction vessel in a detoxifying device, longer operation is possible. Become capable,
(B) Addition of Nb: more than 1.0 to 6% to the Ni-based alloy having the composition described in (a) further improves the stress corrosion cracking resistance.
(C) When one or two of Mo: 0.01 to less than 0.5% and Hf: 0.01 to 0.1% are further added to the Ni-based alloy having the composition described in (a) above. , Stress corrosion cracking resistance is further improved,
(D) When one or two of Fe: 0.1 to 10% and Si: 0.01 to 0.1% are further added to the Ni-based alloy having the composition described in (a) above, the strength is increased. Research results such as further improvement were obtained.
[0008]
The present invention has been made based on the results of such research,
(1) Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: 0 0.05% to 0.5%, with the balance being Ni and unavoidable impurities, and having a composition in which the amount of C contained as unavoidable impurities is adjusted to 0.05% or less. Ni-based alloy with excellent stress corrosion cracking property,
(2) Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: 0 0.05 to 0.5%, Nb: more than 1.0 to 6%, the balance is made of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is adjusted to 0.05% or less. Ni-base alloy having an excellent resistance to stress corrosion cracking in an inorganic acid-containing supercritical water environment having the above composition,
(3) Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: 0 0.05 to 0.5%, Mo: 0.01 to less than 0.5%, and Hf: 0.01 to 0.1% of one or two of them, the balance being Ni And an Ni-based alloy having an excellent resistance to stress corrosion cracking in an inorganic acid-containing supercritical water environment having a composition in which the amount of C contained as an unavoidable impurity is adjusted to 0.05% or less.
(4) Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: 0 0.05 to 0.5%, further containing one or two of Fe: 0.1 to 10% and Si: 0.01 to 0.1%, the balance being from Ni and inevitable impurities A Ni-based alloy excellent in stress corrosion cracking resistance in an inorganic acid-containing supercritical water environment having a composition in which the amount of C contained as an inevitable impurity is adjusted to 0.05% or less,
(5) Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: 0 0.05 to 0.5%, Nb: more than 1.0 to 6%, Mo: 0.01 to less than 0.5%, and Hf: 0.01 to 0.1% The stress resistance in a supercritical water environment containing an inorganic acid having a composition in which the balance is made of Ni and unavoidable impurities and the amount of C contained as unavoidable impurities is adjusted to 0.05% or less. Ni-based alloy with excellent corrosion cracking property,
(6) Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: 0 0.05 to 0.5%, Nb: more than 1.0 to 6%, Fe: 0.1 to 10%, and Si: 0.01 to 0.1% Or two types, the balance is made of Ni and inevitable impurities, and has a composition in which the amount of C contained as inevitable impurities is adjusted to 0.05% or less, stress corrosion cracking resistance in an inorganic acid-containing supercritical water environment Excellent Ni-base alloy,
(7) Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: 0 0.05 to 0.5%, Mo: 0.01 to less than 0.5%, and Hf: 0.01 to 0.1%, or Fe: 0 0.1 to 10% and Si: 0.01 to 0.1% of one or two of them, the balance is made of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is 0.05% or less Ni-based alloy having an inorganic acid-containing supercritical water environment and having excellent resistance to stress corrosion cracking, (8) Cr: more than 36 to less than 42%, W: more than 0.01 to 0.5 %, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: 0.05 to 0.5%, and Nb : More than 1.0 to 6%, further containing one or two of Mo: 0.01 to less than 0.5% and Hf: 0.01 to 0.1%, and further Fe: It contains one or two of 0.1 to 10% and Si: 0.01 to 0.1%, the balance is made of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is 0.05%. Ni-base alloy having excellent resistance to stress corrosion cracking in an inorganic acid-containing supercritical water environment having a composition adjusted as follows:
(9) Supercritical water process reaction comprising a Ni-based alloy having the composition described in (1), (2), (3), (4), (5), (6), (7) or (8) The apparatus member is characterized.
[0009]
Next, the reason for limitation of each element in the alloy composition of the Ni-based alloy of the present invention will be described in detail.
[0010]
Cr, W:
By containing Cr over 36% and W over 0.01%, stress corrosion cracking resistance in a supercritical water environment in which inorganic acids not containing chlorine such as sulfuric acid, phosphoric acid, and hydrofluoric acid are mixed. Although it improves remarkably, if the Cr content is 42% or more, the overall corrosion resistance is lowered in combination with W, so the Cr content is determined to be more than 36 to less than 42%. More preferably, it is more than 38 to 41.5%.
Similarly, when W is contained in an amount of 0.5% or more, the workability is lowered in combination with Cr, which is not preferable. Therefore, the W content is determined to be more than 0.01 to less than 0.5% (more preferably 0.1 to 0.45%).
[0011]
N, Mn and Mg:
By making N, Mn, and Mg coexist, phase stability can be improved. That is, N, Mn, and Mg have the effect of stabilizing the Ni-fcc phase that is the parent phase and making the second layer difficult to precipitate. However, when the N content is less than 0.001%, there is no effect of phase stabilization. On the other hand, when the N content exceeds 0.04%, a nitride is formed and the corrosion resistance in a supercritical water environment deteriorates. Content of 0.001 to 0.04% (more preferably 0.005 to 0.03%).
Similarly, if the content of Mn is less than 0.05%, there is no effect of phase stabilization. On the other hand, if the content exceeds 0.5%, the stress corrosion cracking resistance in an inorganic acid-containing supercritical water environment deteriorates. The Mn content is 0.05 to 0.5% (more preferably, 0.1 to 0.4%).
Similarly, Mg is a component that improves phase stability. However, if its content is less than 0.001%, there is no effect of phase stabilization, whereas if it exceeds 0.05%, it contains inorganic acid-containing supercritical water. Since stress corrosion cracking resistance in the environment deteriorates, the Mg content is set to 0.001 to 0.05% (more preferably 0.010% to 0.040%).
[0012]
Nb:
The effect of further improving the overall corrosion resistance in an oxygen-containing supercritical water environment containing no chlorine by adding Nb to a Ni-based alloy containing Cr: more than 36% and W: more than 0.01% However, if it is contained in excess of 1.0%, the effect is exhibited, but if it exceeds 6%, the phase stability is deteriorated. Therefore, Nb contained in the Ni-based alloy of the present invention is determined to be more than 1.0 to 6%. More preferably, it is 1.1 to less than 3.0%.
[0013]
Mo and Hf:
Mo and Hf are added to a Ni-based alloy containing Cr: more than 36% and W: more than 0.01% to further increase stress corrosion cracking resistance in a chlorine-free oxygen-containing supercritical water environment. Since it has an effect of improving, it is added as necessary, but in that case, Mo shows an effect by containing over 0.01%, but if it contains 0.5% or more, the phase stability deteriorates. This is not preferable because the stress corrosion cracking resistance in an inorganic acid-containing supercritical water environment deteriorates. Therefore, the Mo content is set to more than 0.01 to less than 0.5% (more preferably, more than 0.1 to less than 0.5%).
Similarly, if Hf is contained in an amount of 0.01% or more, the effect is exhibited, but if it exceeds 0.1%, the stress corrosion cracking resistance in an inorganic acid-containing supercritical water environment deteriorates, which is not preferable. Therefore, the content of Hf is set to 0.01% to 0.1% (more preferably 0.02 to 0.05%).
[0014]
Fe and Si:
Fe and Si have the effect of improving the strength, so they are added as necessary. However, Fe is effective when contained in an amount of 0.1% or more, but if it exceeds 10%, it contains an inorganic acid-containing supercritical water environment. This is not preferable because the corrosion resistance against general corrosion in the steel deteriorates. Therefore, the Fe content is set to 0.1% to 10% (more preferably 0.5 to 4%).
Similarly, if Si is contained in an amount of 0.01% or more, the effect is exhibited, but if it exceeds 0.1%, the phase stability deteriorates, so the resistance to stress corrosion cracking in an inorganic acid-containing supercritical water environment deteriorates. This is not preferable. Therefore, the Si content is set to 0.01% to 0.1% (more preferably 0.02 to 0.05%).
[0015]
C:
C is contained as an unavoidable impurity, but if C is contained in a large amount, Cr and carbide are formed in the vicinity of the grain boundary, and the corrosion resistance against the overall corrosion is deteriorated. Therefore, the smaller the C content, the better. The upper limit of the C content contained in the inevitable impurities is set to 0.05%.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
It melt | dissolved and cast using the normal high frequency melting furnace, and the ingot which has a component composition shown by Tables 1-4 and has thickness: 12 mm was produced. This ingot was subjected to a homogenization heat treatment at 1230 ° C. for 10 hours, held within a range of 1000 to 1230 ° C., and reduced to a thickness of 1 mm by one hot rolling, and finally made 5 mm thick. Further, after being subjected to solution treatment by holding at 1200 ° C. for 30 minutes and water quenching, the surface is polished with emery paper # 600, so that the Ni-based alloy plates 1 to 42 of the present invention, the comparative Ni-based alloy plate 1 To 11 and conventional Ni-based alloy plates 1 to 3 were produced.
In order to give internal stress and internal strain to these Ni-base alloy plates 1 to 42, comparative Ni-base alloy plates 1 to 11 and conventional Ni-base alloy plates 1 to 3 according to the present invention, they are cold-rolled at a reduction rate of 30%. Each 3.5 mm thick plate was produced. This plate was cut to prepare a solid solution test piece having a rectangular parallelepiped shape having dimensions of 4 mm in length, 4 mm in width, and 3.5 mm in height.
Further, in order to evaluate the effect of phase stability on the stress corrosion cracking resistance in an inorganic acid-containing supercritical water environment, the present invention Ni-based alloy plates 1 to 42, comparative Ni-based alloy plates 1 to 11 and Conventional Ni-base alloy plates 1 to 3 are subjected to aging treatment at 450 ° C. for 10,000 hours, then polished with emery paper # 600, and cold-rolled at a reduction rate of 30% to give internal stress and internal strain. Then, plates each having a thickness of 3.5 mm were prepared, and this plate was cut to prepare an aging material test piece having a rectangular parallelepiped shape having dimensions of 4 mm in length, 4 mm in width, and 3.5 mm in height.
[0017]
Next, a flow-type corrosion test apparatus was prepared in which a titanium / Hastelloy C-276 double pipe with titanium on the inside and Hastelloy C-276 on the outside was an autoclave. This flow-through type corrosion test apparatus presses a test solution from one end of a titanium / Hastelloy C-276 double pipe with a high-pressure pump, and heats the test solution with a heater provided at the pipe end, thereby performing a predetermined corrosion test. The test solution that has formed a condition and has come out from the other end is collected in a reservoir tank through a pressure reducing valve.
[0018]
Furthermore, supercritical water in which sulfuric acid: 0.2 mol / kg and phosphoric acid: 0.2 mol / kg were mixed with supercritical water of fluid temperature: 500 ° C., pressure: 60 MPa, dissolved oxygen amount: 800 ppm (added as hydrogen peroxide) Water was prepared as a test solution.
This supercritical water mixed with sulfuric acid and phosphoric acid is a supercritical aqueous solution expected to be generated when VX gas is decomposed and oxidized with supercritical water. Hereinafter, this supercritical water containing sulfuric acid and phosphoric acid is used. The critical aqueous solution is referred to as a VX gas decomposition simulation solution.
[0019]
Furthermore, the supercritical water of fluid temperature: 500 ° C., pressure: 60 MPa, dissolved oxygen amount: 800 ppm (added as hydrogen peroxide), phosphoric acid: 0.4 mol / kg, hydrofluoric acid: 0.14 mol / kg Critical water was prepared as a test solution.
The supercritical water in which phosphoric acid and hydrofluoric acid are mixed is a supercritical aqueous solution expected to be generated when GB (saline) gas is decomposed and oxidized with supercritical water. A supercritical aqueous solution containing an acid is referred to as a GB gas decomposition simulation solution.
[0020]
The VX gas decomposition simulation liquid and GB gas decomposition simulation liquid are pressed into a titanium / Hastelloy C-276 double pipe in a flow-type corrosion test apparatus prepared in advance, and the PCB or dioxin decomposition simulation liquid inside the double pipe is injected. Is controlled to flow at a flow rate of 6 g / min to form an inorganic acid-containing supercritical water environment, and in this environment, the Ni-based alloy plates 1 to 42 of the present invention, the comparative Ni-based alloy plates 1 to 11 and the conventional Ni-based alloy plates The presence or absence of stress corrosion cracking on the surface of the test piece was confirmed by holding the solution test piece consisting of the base alloy plates 1 to 3 for 100 hours, and the results are shown in Tables 5-6.
[0021]
Further, in order to evaluate the effect of phase stability on the stress corrosion cracking resistance in an inorganic acid-containing supercritical water environment, the present invention Ni-based alloy plates 1 to 42, comparative Ni-based alloy plates 1 to 11 and The presence or absence of stress corrosion cracking on the surface of the aging material test piece is confirmed by holding the aging material test piece consisting of the conventional Ni-based alloy plates 1 to 3 in the above-described inorganic acid-containing supercritical water environment for 100 hours. It showed to Tables 5-6.
[0022]
[Table 1]

[0023]
[Table 2]

[0024]
[Table 3]

[0025]
[Table 4]

[0026]
[Table 5]

[0027]
[Table 6]

[0028]
From the results shown in Tables 1 to 6, the Ni-base alloy plates 1 to 42 of the present invention are the solution corrosion test pieces and the aging material test pieces, both of which are stress corrosion cracks as found in the conventional Ni-base alloy plates 1 and 2. Therefore, it can be seen that the stress corrosion cracking resistance is excellent. However, stress corrosion cracking occurs in at least one of the solid solution material test pieces and the aging material test pieces of the comparative Ni-base alloy plates 1 to 11 having a component composition deviating from the present invention, and significant overall corrosion occurs. It turns out that it is not preferable.
[0029]
【The invention's effect】
As described above, the Ni-based alloy of the present invention can be used for a long period of time because of its excellent resistance to stress corrosion cracking in a supercritical water environment containing sulfuric acid and phosphoric acid, or phosphoric acid and hydrofluoric acid. In addition, it provides excellent effects on the environmental industry such as detoxification of VX gas or GB gas.
The Ni-based alloy of the present invention is most effective when used in a supercritical water environment containing an inorganic acid not containing chlorine, such as sulfuric acid, phosphoric acid, and hydrofluoric acid, as described above, but is limited to this. It can also be used in supercritical water environments containing hydrochloric acid and nitric acid, supercritical water environments containing chloride salts such as sodium chloride, magnesium chloride, calcium chloride, and supercritical water environments containing ammonia. It can also be applied to supercritical water equipment materials for disposal of waste, nuclear power related waste, electronic power related waste, and general industrial waste.
Further, when the Ni-based alloy of the present invention is used as a reaction chamber of the apparatus main body, the outer side may be made of a strength material such as stainless steel, and the Ni-based alloy of the present invention may be clad or lined on the inner surface.

Claims (9)

In mass%, Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: Inorganic acid-containing supercriticality characterized in that it contains 0.05 to 0.5%, the balance is made of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is adjusted to 0.05% or less Ni-based alloy with excellent stress corrosion cracking resistance in water environments. In mass%, Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: Containing 0.05-0.5%,
Further, Nb: more than 1.0 to 6%,
Excellent balance of stress corrosion cracking resistance in supercritical water environment containing inorganic acid, characterized in that the balance consists of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is adjusted to 0.05% or less. Ni-based alloy. In mass%, Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: Containing 0.05-0.5%,
Furthermore, it contains one or two of Mo: 0.01 to less than 0.5% and Hf: 0.01 to 0.1%,
Excellent balance of stress corrosion cracking resistance in supercritical water environment containing inorganic acid, characterized in that the balance consists of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is adjusted to 0.05% or less. Ni-based alloy. In mass%, Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: Containing 0.05-0.5%,
Furthermore, it contains one or two of Fe: 0.1 to 10% and Si: 0.01 to 0.1%,
Excellent balance of stress corrosion cracking resistance in supercritical water environment containing inorganic acid, characterized in that the balance consists of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is adjusted to 0.05% or less. Ni-based alloy. In mass%, Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: Containing 0.05-0.5%,
Further, Nb: more than 1.0 to 6%,
Furthermore, it contains one or two of Mo: 0.01 to less than 0.5% and Hf: 0.01 to 0.1%,
Excellent balance of stress corrosion cracking resistance in supercritical water environment containing inorganic acid, characterized in that the balance consists of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is adjusted to 0.05% or less. Ni-based alloy. In mass%, Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: Containing 0.05-0.5%,
Further, Nb: more than 1.0 to 6%,
Furthermore, it contains one or two of Fe: 0.1 to 10% and Si: 0.01 to 0.1%,
Excellent balance of stress corrosion cracking resistance in supercritical water environment containing inorganic acid, characterized in that the balance consists of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is adjusted to 0.05% or less. Ni-based alloy. In mass%, Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: Containing 0.05-0.5%,
Furthermore, it contains one or two of Mo: 0.01 to less than 0.5% and Hf: 0.01 to 0.1%,
Furthermore, it contains one or two of Fe: 0.1 to 10% and Si: 0.01 to 0.1%,
Excellent balance of stress corrosion cracking resistance in supercritical water environment containing inorganic acid, characterized in that the balance consists of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is adjusted to 0.05% or less. Ni-based alloy. In mass%, Cr: more than 36 to less than 42%, W: more than 0.01 to less than 0.5%, Mg: 0.001 to 0.05%, N: 0.001 to 0.04%, Mn: Containing 0.05-0.5%,
Further, Nb: more than 1.0 to 6%,
Furthermore, it contains one or two of Mo: 0.01 to less than 0.5% and Hf: 0.01 to 0.1%,
Furthermore, it contains one or two of Fe: 0.1 to 10% and Si: 0.01 to 0.1%,
Excellent balance of stress corrosion cracking resistance in supercritical water environment containing inorganic acid, characterized in that the balance consists of Ni and inevitable impurities, and the amount of C contained as inevitable impurities is adjusted to 0.05% or less. Ni-based alloy. A member for a supercritical water process reactor, comprising a Ni-based alloy having the composition according to claim 1, 2, 3, 4, 5, 6, 7 or 8.