JPS60110856A - Production of precipitation hardening nickel-base alloy - Google Patents

Abstract

PURPOSE:To obtain a precipitation hardening Ni-base alloy having excellent resistance to corrosion as well as high strength and high toughness by subjecting the Ni-base alloy which contains Cr at a high rate and Ti at a decreased rate and is added mainly with Nb and Al to specific hot working and heat treatment in combination. CONSTITUTION:An alloy contg. <=0.050% C, <=0.50% Si, <=2.0%Mn, 45-60% Ni, 18-27% Cr, <=0.40% Ti, <=1 kind of 2.5-5.5% Mo and <=11% W, >=1 kind among 0.3-2.0% Al, <=0.015% P and 2.5-5.0% Nb, <=0.0050% S, <=0.030% N and a specific amt. of Cu, Co, Mg, Fe, etc. is melted. Such alloy is subjected to hot rolling to >=50% reduction rate of area at 1,200-800 deg.C and is held for 3min-5hr at 1,000-1,200 deg.C. The alloy is cooled at a cooling rate above air cooling and is subjected to >=1 time of aging treatment at 500-750 deg.C. The precipitation hardening Ni-base alloy having the excellent resistance to stress corrosion cracking and hydrogen cracking is obtd.

Description

Detailed Description of the Invention The present invention provides good stress corrosion cracking resistance and hydrogen cracking resistance in a corrosive environment, in which q6 contains one or more of hydrogen sulfide, carbon dioxide, and chlorine ions. The present invention relates to a method for producing a high-strength, high-toughness nickel-based alloy material.

Traditionally, metal parts that require high strength and high corrosion resistance, such as structural parts for equipment in oil wells, chemical industries, geothermal power generation, etc., have been processed by (solid solution strengthening) - (cold working strengthening). ``ζ Strength'' Since most of the measurements were performed on digastric strength, it is difficult to increase the strength with the conventional methods described above for metal parts that have complicated or special shapes that cannot be subjected to cold working. was difficult.

On the other hand, a method that has been known since 17L as a strength increasing method that can be applied to parts with special shapes is that the alloy composition is Ti.
and adding AQ or Nb to Ni3 (Ti, A
Q) or an intermetallic compound mainly composed of Ni
It is possible to precipitate an intermetallic compound (γ'' phase) mainly composed of 3Nb.This precipitation strengthening can be used to form the intermetallic compound (γ'' phase). There are Ni-based alloys such as Ni-based alloys such as Ni-based alloys, but because of the low Ti content, Ni 3 Ti precipitates and the corrosion resistance deteriorates. For example, Inconel-718 etc. It is a precipitation-strengthened Ni-based alloy that mainly undergoes precipitation strengthening in the γ' phase, but there is a considerable amount of Ti: q, 0.7%.Because Ti precipitates, the corrosion resistance is not necessarily good. There wasn't.

However, high strength and high In addition to toughness, excellent corrosion resistance, ie, resistance to stress corrosion cracking and resistance to hydrogen cracking, is required. In the case of materials used as structural materials in such applications, it is desirable to increase the strength of materials that are relatively easy to form, such as plates or pipes, by cold working, but it is desirable to increase the strength of materials such as valves, joints, piping, etc. For products with special shapes that cannot be subjected to temporary processing, the strength must be increased by precipitation strengthening. However, according to the results of the research conducted by the present inventors, the conventional precipitation-strengthened alloys mentioned above, which are mostly γ' precipitation-strengthened Ni-based alloys due to the addition of Ti and AQ, inherently have poor corrosion resistance. I found out that.

For example, if an alloy with good resistance to stress corrosion cracking is used,
What is disclosed in Publication No. 7=203741 contains combined addition of Nl+ and Ti (also 8Q), so that the aging treatment causes r'-Ni3 (Ti, #2) and T''-
Two intermetallic compounds, Ni3Nb, are mainly precipitated, but due to the large amount of Ti added, overaging is likely to occur, and when intermetallic compounds of η~Ni3Ti are precipitated as the overaging precipitation phase, corrosion resistance, especially hydrogen cracking resistance, deteriorates. Significant deterioration. In order to improve this corrosion resistance, it is necessary to strictly limit the heat treatment conditions and the J treatment conditions.

In addition, as a similar alloy, JP-A No. 57-123948 (・u; 1 & is also known, but this also contains Ti.
A large amount of Ti is added (1'i, 8Q), resulting in poor corrosion resistance.As can be seen from the fact that a lower limit has been set for the amount of Ti added, Ni3 (1'i, 8Q) is intended to precipitate.

Sogo C1, the present inventors, 4!11 head 1986-109
No. 422, Zunawaji γ'-Ni3'l'i is analyzed in 11-4'. Like Ti
Discloses a method that solved the problem of corrosion resistance deterioration of additive alloys (1'i, the same applies to Nb composite additions) by selecting the composition system of Ni-based alloys and specifying the conditions for hot working, heat treatment, and aging treatment. did.

Here, as a result of further research, the present inventors found 1.
Entry 11 In the invention, the combined addition of N++ and 8Q has 1. various strengths, ductility, and toughness, as well as resistance to corrosion cracking A:; and hydrogen cracking resistance. It has been found that an extremely excellent +A advantage is obtained in 11, 2) and, if necessary, by adding Go, 1) it is possible to shorten the effective interstitial space to promote precipitation strengthening of the γ' or γ'' phase,
The invention has been completed.

Here, the gist of the present invention is that C20.050
% or less, Si: 0.50% or less, Mn: 2.0
% or less, -Ni: 45-60%, Cr: 18-27
%, Ti: 0.40% or less, Mo: 2.5~
5.5% and at least one type of 11% or less (however, 2.5%≦Mo++AW≦5.5%), AQ: 2.0% or less, P: 0.015% or less,
Nb: 2.5-5.0% and Ta: 2.0%
At least 11 weights of the following (however, 2.5%≦Nb-1
- Ta≦5.0%), S: o, ooso% or less, N: o, o3o% or less, and if necessary, Cu: 2.0% or less and CO:
2.0% or less of at least one species and/or REM
: o, to% or less, M, : 0.10% or less, Ca:
An alloy having a composition consisting of at least one of 0.10% or less and Y: 0.20% or less, and the remainder A (J impurity and After hot working, 1 (10
After holding at 0 to 1200°C for 3 minutes to 5 hours, cool at a cooling rate higher than air cooling (however, between 900 and 500°C, cool at a cooling rate of 10°C/min or less), then 50°C.
Manufactures a precipitation-strengthened nickel-based alloy with excellent stress corrosion cracking resistance and hydrogen cracking resistance by subjecting it to one or two aging treatments at 0 to 750°C for 1 to 200 hours. This is the way to do it.

Furthermore, in another aspect of the present invention, the alloy composition includes Ni: 40 to 60% and Co: more than 2.0% and 15% or less.

1st position) 'E+, Thus, according to the present invention, hydrogen sulfide-' oxidation contains one or more types of sodium and chloride ions, such as Urano 1°, chemical industry, and geothermal power generation environments. Odor - (Has good stress corrosion cracking resistance and hydrogen cracking resistance, and is also suitable for oil well valve bodies.
Because of its 6-shaped shape, it has high strength even when used in parts that do not undergo cold working.
The alloy composition is composed mainly of Nb and AQ additions with suppressed i additions, and this is subjected to specific hot working and east! By combining and applying 5 treatments, high strength with extremely good corrosion resistance,
A precipitation-strengthened Ni-based alloy exhibiting high toughness can be obtained.

Therefore, according to one feature of the present invention, as a method for improving the corrosion resistance of conventional precipitation-strengthened Ni-based alloys, based on the above-mentioned knowledge, the amount of Ti added is suppressed compared to the conventional method, and Nb and AQ
Ni 3 Nb or Ni 3 (N
b, AQ>, which are intermetallic compounds, and the heat treatment conditions and aging conditions are specified in order to effectively carry out this precipitation strengthening.

According to another feature of the present invention, the addition of Co promotes precipitation strengthening of the T' phase and the γ'' phase, making it possible to shorten the reno time, and furthermore, the addition of Co does not cause deterioration of corrosion resistance. It is something.

The reason why the alloy composition and processing conditions are limited as described above in the present invention will be explained in more detail below.

1) Chemical composition Ni... The alloy in the present invention has Ni 3 (Nb, AQ) or Ni3Nb in the austenite base.
The basic principle is that the T” phase or γ′ phase, which is an intermetallic compound of Cr and M, precipitates and strengthens through aging.
os σ and μ depending on the balance of the added amounts of Fe and Go.
, P, Laves phase and other intermetallic compounds that are unfavorable for ductility, toughness, and corrosion resistance (hereinafter referred to as TCP phase)
A sufficient amount is required to stabilize the austenite base so as not to generate it, and for that purpose, the former should be ≧45%. However, if Go exceeds 2.0%, Ni
240% is sufficient. Further, if the content exceeds 60%, the hydrogen cracking resistance deteriorates significantly, so Ni is preferably 560%, but preferably 50%≦Ni≦55% as a range that satisfies both strength and toughness.

Cr, , , , improves corrosion resistance together with Mo. For this purpose, 18% or more is required, but if it exceeds 27%, hot workability decreases.1. Furthermore, TCP phase is more likely to be generated. Preferably, Cr is 22-27%.

M (1, W, ..., particularly improves pitting corrosion resistance by coexistence with Cr).The effect is noticeable, for example, when Mo2.5% or more is added, but as with Cr, the addition of a large amount increases TC.
It is desirable to add Mo in an amount of 5.5% or more since the P phase is likely to be generated. Although W exhibits the same effect as Mo, it is necessary to add twice the amount of Mo to obtain the same effect. Therefore, if the amount of Mo required is small at that ratio (it is also possible to partially replace the old one), if ζ is added in excess of 11%, intermetallic compounds such as two series are likely to be generated, similar to Mo. Therefore, in the present invention, at least one of Mo: 2.5 to 5.5% and Mo: 11% or less (however, 2.5%≦Mo+ %W≦5
．． 5%). Outside these ranges, corrosion resistance will not be improved sufficiently and ductility and toughness will deteriorate.

Ti, , , , If Ti exceeds 0.40%, Ni 3
Since Ti precipitates as Ti and significantly deteriorates corrosion resistance, especially hydrogen cracking resistance, Ti: 0.40% or less, but in order to stably obtain hydrogen cracking resistance, Ti:
0.2 [1% or less.

In addition to the deoxidizing effect, AQ, .

Precipitation strengthening behavior changes depending on the balance of addition amount with Nb. When considering only the deoxidizing effect, AQ is 0.30%.
However, in order to obtain effective precipitation strengthening as Ni3 (Nb, AQ), AQo of 3% or more is required. In particular, when the Co content is 2% or less, it is necessary to add 8Q to strengthen the steel. Further, even when Co exceeds 2%, even higher strength can be obtained by actively adding 0.3% or more of AQ. On the other hand, the addition of a large amount of 8Q';l: T
The AQ was set to 2.0% or less to encourage C11 phase formation.

Nb, 1'r+,..., Nl+ is Ni3Nb or old s (Nb, A(2), which contributes to an increase in -r precipitation strength. The "C" precipitation strengthening behavior changes depending on the balance of addition amount with AQ. However, the effect of adding Nb is that Nb is 2.5%
On the other hand, if it exceeds 5.0%, hot workability decreases and TCII phase tends to form. Outside these ranges, there is no improvement in strength, and rather the ductility and toughness deteriorate. Since Ta exhibits the same effect as Nb, a portion of Nb may be replaced with Ta, but the added J is approximately 1/2 of N11. Therefore, in the present invention, Nb: 2.5 to 5.0% and Ta:
2.0% or less of at least one species 2.5%≦Nb +
'A Add TaS within the range of 2.0%.

c, , , , , hinders precipitation strengthening and also 0.0
When it exceeds 50%, the amount of inclusions such as NbC and TiC increases, resulting in deterioration of ductility, toughness, and corrosion resistance. Preferably CS2
．． However, when C'≦0.010%, the ductility, toughness, and corrosion resistance are further improved.

SisMn, , SiSMn are added as a deoxidizing agent and a desulfurizing agent, respectively, but if Si exceeds 0.50%, TCP phase tends to be generated, so Si: 0.50
% or less. Considering weldability: Then Sis0.10%
is preferred. Furthermore, regarding Mn, MnS2.0
%, but preferably MnS2°80%.

p, s, , , p, s decreases hot working due to grain boundary segregation and also deteriorates corrosion resistance, so P≦0.01
5%, S≦0.0050%, preferably S≦0°00IO% to further improve hot workability.

Since N increases the amount of inclusions and causes anisotropy of material properties, N≦0.030%.
In order to further improve the ductility and toughness in terms of fly Ra, it is preferable that N≦0.010%.

An appropriate amount of Fe is required to promote precipitation strengthening depending on the balance with the amount of Ni added, and the remainder of the alloy composition is Fe, excluding incidental impurities. Preferably, 3.
0%≦Fe≦25%. However, Go: 2.0
When adding more than %, it may be 3.0≦t≦20%.

Cu, Go, 1. Although it is self-effective in improving corrosion resistance, the effect is saturated when it exceeds 2.0%, so Cu, Go≦
2°0%.

However, when actively utilizing h-extrusion strengthening (by adding Co), Co is added in excess of 2.0%, and depending on the balance with the amount of Ni and Pe added, the precipitation of γ1 or γ'' phase is promoted and the strength is increased. This effect becomes noticeable when Co exceeds 2.0%, but if it exceeds 15%, the TCP phase tends to form, so it was set to 2.0%<00615%.

Old rM, +1+i, Ca, Y,... These elements improve hot workability by adding at least one small amount of 0.10%, 0.10%, 0.10% and 0, respectively. , 2 (If the upper limit of 1% is exceeded, low melting point compounds are more likely to be produced, and the duality is decreased).

f3. ,,,,,,. The purpose of adding 13 is to improve hot workability and toughness, and 0.10% is added as necessary.
Add the following.

In addition, trace amounts of Sn, Zn, Pb, etc. do not affect the properties of the alloy obtained by the present invention, so up to 0.10% of each is allowed as impurities, but if this upper limit is exceeded, the workability or corrosion resistance deteriorates. deteriorates.

2) Hot processing] 2) When Nb is added as in the present invention, low melting point compounds tend to be generated at grain boundaries during solidification, which limits the heating temperature and processing temperature range during hot processing. There is a need. When the starting temperature of hot working exceeds 1200°C, weakening of grain boundaries is observed. On the other hand, if the finishing temperature is less than 800°C, processing becomes difficult. In the present invention, therefore, 12
Temperature range of 00-800°C, preferably 1150-8
Hot working is carried out at 50°C.

Furthermore, Nb, Mo, etc. tend to cause macro segregation during solidification, and if such segregation remains in products, it becomes a factor in deterioration of toughness and corrosion resistance in thick-walled materials.

For this reason, the degree of hot working from the ingot to the product is set to 50% or more in area reduction rate to prevent macro segregation of Nb, Mo, etc.

3) In order to effectively precipitate the γ゛ phase or T'' phase by heat treatment aging, complete solution treatment is necessary. Therefore, in the present invention, 10Of)''c~1200
℃, preferably 1050-1150℃ for 3 minutes to 5.0
After cooling for a time (^), cool at a cooling rate higher than air cooling.Especially when cooling! 10 (Since brittle phases tend to precipitate between 1℃ and 500℃, the cooling rate in the temperature range between 1℃ and 500℃ is 10℃/min or higher. Cooling at "ζ" suppresses the precipitation of such brittle phases.

4) Aging treatment In the case of the alloy which can be t8 according to the present invention, Ni
3 (Nb, AQ) or Ni3Nb is uniformly dispersed and precipitated in the austenite matrix, resulting in high strength, good ductility, toughness, and corrosion resistance. The precipitation strengthening behavior due to aging varies depending on the solution treatment conditions and the amounts of Nb and AQ added, as well as the amounts of Ni, Go, and Pe. However, at high temperature aging exceeding 750'C, over-aging occurs and the first agglomeration of γ゛ phase or γ゛ phase occurs.
+j for increasing the size or generating TCP phase! 11 degrees/Toughness decreases. The selection of one hour for aging varies depending on the aging temperature. Self-effect precipitation strengthening occurs in 1 to 200 hours.
However, sufficient strength can be obtained even after 5 to 20 hours. In order to obtain stable strength, ductility, toughness, and corrosion resistance, it is preferable that the treatment is such that the γ'' phase or γ'' phase is finely and uniformly precipitated in the austenite base of the matrix.

In addition, in the present invention, when aging treatment is performed two or more times,
For the aging treatment in the subsequent stages, the aging treatment may be performed by cooling to around room temperature after the aging treatment in the previous stage and then reheating.
The aging treatment may be performed by heating or cooling (at a rate higher than furnace cooling) from the aging treatment temperature in the first stage to the aging treatment temperature in the next stage. In either case, there is no noticeable difference in strength, toughness, or corrosion resistance.

Thus, according to the method of the present invention, the mechanical properties are 0.
．． 2% proof stress ≧63kgf/crystal (preferably ≧17kg
f/product), elongation 220%, aperture 230% and impact value ≧
5kgf-m/ctM (preferably ≧10kgLm
/cnt) and excellent corrosion resistance, that is, stress corrosion cracking resistance and hydrogen cracking resistance.

The alloy obtained by the present invention can obtain high strength through precipitation strengthening of the T' phase or γ'' phase, so it can be used in special shaped products such as valve bodies for oil country tubular goods to which strengthening methods such as cold working cannot be applied. However, it can be molded with good strength, toughness and corrosion resistance.

Next, the present invention will be further explained based on examples.
x Oh, Tai I month 1t 111 Lou Otsu 7 Seal Y Maki L7 Please note that (not clear) ``-%'' is ``weight %''.

Xk discharge [For each alloy having the chemical composition shown in Table 1 of the lower finger,
Also shown in Table 2 are J hot working conditions and heat treatment conditions.
A precipitation-strengthened nickel-based alloy was produced under aging treatment conditions.

The mechanical properties and corrosion resistance test results of the iM alloys are also summarized in Table 2.

The tensile test was conducted using a diameter of 3.5 mm and a gauge length of 1i11t20.
．． The test was carried out using a 0-fight test stick. i! The impact value is based on the Charpy impact test, and is 5.0 mm x
A test piece with a size of 10 mm x 55 mm and a 2.0 mm V-notch was used. Test temperature: 0
It was ℃.

111iJ eating property was determined in the stress corrosion cracking test by 25%N.
aCl-0,5%Cll3C00II-15+it
m II 2 S5-1 Oat CO2 solution (pH=
2) and was tested and evaluated at 250°C. In addition, for the hydrogen cracking test, NAC [conditions (5% NaCl
-0,5% Cll 3CO (ill-1a Lm If
2 S) using carbon steel compling, I? 0.2
The test was conducted at 25°C using a test piece with a 5U notch.

In Table 2, 0゛ means the case where there was no cracking.
The comparative examples are within the range of the composition of the alloy used in the method of the present invention, but
Items that deviate from the conditions of ripe processing, heat treatment, and aging treatment are shown as Nos. 25 to 30, and items that are within the range of treatment conditions but whose alloy components are out of range are shown as positive 31 to 36. In the comparative examples, one or more of strength, ductility, toughness, and corrosion resistance are not good.

Nos. 037 to 44 are shown for comparison with the conventional precipitation-strengthened alloys containing Ti and AQ, which were obtained by the method of the present invention. Many of these conventional alloys have good strength, but their corrosion resistance deteriorates due to their nature.On the other hand, in order to improve such corrosion resistance, strength must be sacrificed; cannot be obtained.

For each alloy having the chemical composition shown in Table 3 of Jitsubishi I Lower Finger,
Similarly, precipitation-strengthened nickel-based alloys were produced under the hot working conditions, heat treatment conditions, and aging treatment conditions shown in Table 4.

The mechanical properties and corrosion resistance test results of the obtained alloys are also summarized in Table 4.

The test method was the same as that described in Example 1.

Although the comparative examples are within the composition range of the alloy used in the method of the present invention, each strip of hot working, heat treatment, and aging treatment is
ft, 21 to 26, and those with a small amount of Go added, although the processing conditions are within the range, are 27.
- Not shown in 33. In the comparative examples No. 21 to 26,
All of them are not good in strength, ductility, or toughness.

In addition, in Nos. 27 to 33, which are examples of the present invention, C
The aging treatment time required to achieve the same strength (M) is longer than that of the alloy of the present invention when there is a large amount of added charge.

N) 34 to 41 are shown for comparison with the alloy obtained by the method of the present invention for conventional precipitation-strengthened alloys containing Ti and AQ. Many of these conventional alloys have good strength, but their corrosion resistance is
In order to improve such corrosion resistance, G and C must be replaced with C7 at the expense of strength, and it is not possible to obtain good results for both.

In this way, by limiting the range of alloy components and the conditions of hot working, heat treatment, and aging treatment as in the present invention, a material with high corrosion resistance, that is, stress resistance, and high toughness can be obtained. In particular, by adding an appropriate amount of Co, the aging treatment time can be shortened compared to the conventional method.

- Ding Ige 5 Ne Ichimasa Cormorant: (Voluntary) August 1, 1980 Special #'l'Ii' j1 Official Shiga Manabu Tono 1, Indication of the incident 1988 'P'it' [1 No. 217774 No. 2, Name of the invention, Process for producing precipitation-strengthened NiSO-based alloy 3, Relationship to the case of the person who made the amendment 14 Patent applicant address: 5-15 Kitahama, Hitohana Yamato-ku Name (211) Sumitomo Kinku Industrial Co., Ltd. 4, the furigana column of the invention of the agent store and the details of the specification, (
Explanation column (attached sheet) (1) In the inventor's indication column on page 2 of the application, the furigana of the inventor "Takeo Kudo" was incorrectly written as "1-Kudo Toshio" when it should have been "Kudo Takeo." , I have now submitted a correction Wi document and corrected the display to the correct furigana.

(2) The description in the following section of the specification has been corrected as follows.

Gu Hill Original■-Reversed rff, l Tragedy-I 7 From below
8 hours AQ: 2.0% or less 8Q: 0.3-2.
0%9 G Co:2. (1% correct fJ A!:):2.
(Below 1%, Co: Over 2.0% 12 From the bottom 3 Especially... -Deleted-132fU.

17 From bottom 1 to 700℃ to 750℃ 26.27.2
8 Table 2 kgf/(1:3 kgf/mm2 "0.
2% Yield Strength" column shell row -1>=! : (Diiu!, rJj) 11.26.27.28 "Tensile strength j kgf/(ri kgf/opening 2 column" in Table 2) "0.2" in the "Alloy spacing 7" column of Table 2 The value of 0.2% proof stress in the "% proof stress" column is "84", but it is "96".
81 correct.

〃 The value of 0.2% proof stress in l1i1 of ``10.2% proof stress of Alloy N08'' row in Table 2 is corrected as ``96'' to r84J.

26 In Table 2, “Tensile strength” in the row of “Alloy N07” (
1, the value of tensile strength is rl17 J.
12! Correct IJ and Ii1.

... In the 2nd A- [Alloy No. 8 J column, "Tensile strength", the value of tensile strength is r129 J, and Ill correct it to 1'117 J.

3) 2 Determining the 10.2% resistance Jf / (kgf / mm 2 force) in Table 4 Column ``Tensile strength'' in Table 2 (3) Separate pages 30 and 31 of the specification Correct as follows.

kl"2

Claims (1)

[Claims] (+) c: [), 050% or less, Si: 0.
50% or less, Mn 2.0% or less, old: 45-60
%, Cr: 1B~27%, Ti: 0.40%
Below, at least one of Mo: 2°5 to 5°5% and Mo: 11% or less (however, 2.5%≦Mo+'A
H≦5.5%), 8Q: 0.3-2.0%, P: 0.015% or less, Nh: 2.5-5. (1% and Ta ~2.0
% or less (however, 2.5%≦Nb −
l-% TaS2.0%), S: 0.0051)% or less, N: o, o3o% or less, and if necessary, u: 2.0% or less and CO;
2.0% or less of at least one species and/or R15
M: (1.10% or less, Mg: 0.10% or less, C
An alloy having a composition consisting of at least one residual incidental impurity and Fe of a: 0.1% or less and y: o, zo% or less is kept at 1200 to 800°C with a cross section for 3 minutes to 5 hours, and then air cooled or more. Cool at a cooling rate of 10°C/min or more between 900 and 500°C.
cooling at a cooling rate of 8 degrees), then 500-750'
A method for producing a precipitation-strengthened nickel-based alloy with excellent stress corrosion cracking resistance and hydrogen cracking resistance, which comprises subjecting the alloy to aging treatment for 1 to 200 hours with C once or twice or more. (21CiO, 050% or less, Si: 0.50%
Below, Mn: 2.0% or less, Ni: 40-6
0%, Cr: 1B to 27%, Ti: 0.40% or less, Mo: 2.5 to 5.5%, and at least one of 1211% or less (however, 2.5%≦Mo+!4W
55.5%), AQ knee less than 0.3%, P: 0.015% or less,
Nb: 2.5-5.0% and Ta: 2.0%
At least one of the following (however, 2.5%≦Nb+!4
Ta≦5.0%). S: o, ooso% or less, N: o, o3o% or lessC
o: more than 2.0%, 15% or less, and if necessary, Cu: 2.0% or less, and/
or B: O, 10% or less, and/or RFSM
:010J lower-Ha :0-1[1%la lower-C
a:0. 1O% or less and Y20. 20% or less of at least one type; ↓Wealth 7 Ni I200-800'C
After hot working with a cross-section reduction rate of 50% or more,
After holding at 0 to 1200°C for 3 minutes to 5114 minutes, it is cooled at a cooling rate higher than that of air cooling, and then cooled at a cooling rate of 10°C/min or higher between 900 and 500°C), then 50°C.
Manufacture of 1Ji-strengthened Nisokel-based alloy with excellent stress corrosion cracking resistance and hydrogen cracking resistance by subjecting it to aging treatment at 0 to 750°C for 1 hour to 20011.7 times or more. I have a lot of power. (3) C: (1, (150% or less, Si: 0.5
0% or less, Mn: 2.0% or less, Ni: 40
~60%, Cr: 18-27%, Ti: 0.
40% or less, FIo: 2y5-5.5% and meeting:
11% or less of at least one species (however, 2.5%≦Mo
+ %W≦5.5%), HaQ: 0.3-2.0%, p: 0.015% or less, N
b: 2.5-5.0% and Ta: at least one of 2.0% or less (however, 2.5%≦Nb+', 4
(Ta≦5.0%), S: 0.0050% or less, N: o, oao% or less, Co: more than 2.0%, 15% or less, and if necessary, Cu: 2.0% or less, and/
Also B: 0.10% or less and/or 17 [iM
: 0.10% or less, h: 0.10% or less, Ca
: 0.10% or less and Y: 0.20% or less, and the remainder is incidental impurities and Fe. After applying, 1000
After holding at ~1200'c for 3 minutes to 5 hours, cool at a cooling rate higher than air cooling (provided that between 900 and 500'c, cool at a cooling rate higher than 10'C/min), then at 500°C.
Consisting of aging treatment for ~200 hours at ~750'C once or twice, i! A method for producing a precipitation-strengthened nickel-based alloy with excellent stress corrosion cracking resistance and hydrogen cracking resistance.