KR102169790B1 - Acid and alkali resistant ni-cr-mo-cu alloys with critical contents of chromium and copper - Google Patents

Abstract

Nickel-chromium-molybdenum-copper alloy resistant to 70% sulfuric acid at 93° C. and 50% sodium hydroxide at 121° C. for acid and alkali neutralization in the field of waste treatment; The alloy may be from 27 to 33 chromium, 4.9 to 7.8 molybdenum, 3.1 to 6.0 wt.% copper (when chromium is 30 to 33 wt.%), or 4.7 to 6.0 wt.% copper (chrome is 27 to 7.8 wt.%), by weight percentage. 29.9 wt.%), up to 3.0 iron, 0.3 to 1.0 manganese, 0.1 to 0.5 aluminum, 0.1 to 0.8 silicon, 0.01 to 0.11 carbon, up to 0.13 nitrogen, up to 0.05 magnesium, up to 0.05 rare earth elements, and nickel and impurities. Contains the balance. Titanium or another MC carbide former can be added to enhance the thermal stability of the alloy.

Description

Acid and alkali resistant nickel-chromium-molybdenum-copper alloy with critical content of chromium and copper {ACID AND ALKALI RESISTANT NI-CR-MO-CU ALLOYS WITH CRITICAL CONTENTS OF CHROMIUM AND COPPER}

The present invention is a nickel-chromium-molybdenum-copper alloy that provides a useful combination of a generally non-ferrous alloy composition, more specifically a resistance to 70% sulfuric acid at 93° C. and a resistance to 50% sodium hydroxide at 121° C. It is about.

In the field of waste treatment, there is a need for metallic materials that withstand hot, strong acids and hot, strong caustic alkalis. This is because such chemicals are used to neutralize each other, resulting in more stable and less harmful compounds. Among the acids used in industry, sulfuric acid is the most important in terms of yield. Among the caustic alkalis, sodium hydroxide (caustic soda) is most commonly used.

Certain nickel alloys are strong and very resistant to hot sulfuric acid. Certain other nickel alloys are very resistant to hot, strong sodium hydroxide. However, none of them possess adequate resistance to both chemicals.

Typically, nickel alloys with high alloy content are used to withstand sulfuric acid and other strong acids, and the most resistant are nickel-molybdenum and nickel-chromium-molybdenum alloys.

In contrast, pure nickel (UNS N02200/alloy 200) or a nickel alloy with a low alloy content is the most resistant to sodium hydroxide. Where higher strength is required, nickel-copper and nickel-chromium alloys are used. In particular, alloys 400 (Ni-Cu, UNS N04400) and 600 (Ni-Cr, UNS N06600) possess good resistance to corrosion in sodium hydroxide.

During the discovery of the alloys of the present invention, two key environments were used: 70 wt.% sulfuric acid at 200° F. (93° C.) and 50 wt.% sodium hydroxide at 250° F. (121° C.). 70 wt.% sulfuric acid is well known to be highly corrosive to metallic materials, and this concentration is a concentration at which the resistance of many materials (including nickel-copper alloys) is impaired as a result of changes in the cathodic reaction (from reduction to oxidation). to be. 50 wt.% sodium hydroxide is the concentration most widely used in industry. In the case of sodium hydroxide, higher temperatures are used to increase internal attack (the main form of nickel alloy decomposition in these chemicals) and thus increase the accuracy of the measurements during subsequent cross-surveys and metallographic tests. Became.

In U.S. Patent No. 6,764,646, Crook et al. describe a nickel-chromium-molybdenum-copper alloy that is resistant to sulfuric acid and wet process phosphoric acid. These alloys require copper in the range of 1.6 to 2.9 wt.%, which is lower than the level required to be resistant to 70% sulfuric acid at 93°C and 50% sodium hydroxide at 121°C.

Crook's US Pat. No. 6,280,540 discloses a copper-containing, nickel-chromium-molybdenum alloy commercially available as a C-2000® alloy and corresponding to UNS 06200. They have higher molybdenum levels and lower chromium levels than in the alloys of the present invention and do not have the aforementioned corrosion characteristics.

U.S. Patent No. 6,623,869 to Nishiyama et al. describes a nickel-chromium-copper alloy for metal dusting services at high temperatures, with a maximum copper content of 3 wt.%. This range is below the range required to be resistant to 70% sulfuric acid at 93°C and 50% sodium hydroxide at 121°C. More recent US patent application publications (US 2008/0279716 and US 2010/0034690) by Nishiyama et al. describe additional alloys for resistance to metal dusting and carbonization. The alloys of US 2008/0279716 differ from the alloys of the present invention in that they have a molybdenum limit of 3% or less. The alloys of US 2010/0034690 are of several types, iron-based rather than nickel-based, and have a molybdenum content of 2.5% or less. US published patent application US2011/0236252 to Ueyama et al. discloses a nickel-chromium-molybdenum-copper alloy that is resistant to reducing hydrochloric acid and sulfuric acid. The range given for chromium in these alloys is 20-30% and the range for copper is 2-5%; However, the inventive alloy examples provided in this patent contain up to 23% chromium and up to 3.06% copper, which is more than the level required to be resistant to 70% sulfuric acid at 93°C and 50% sodium hydroxide at 121°C. low.

The main object of the present invention is forged products (sheets, plates, sheets, plates, sheets, plates, sheets, plates, sheets, plates, sheets, plates, sheets, plates, sheets, plates, sheets, plates, sheets, plates, sheets, sheets, plates, It is to provide an alloy that can be processed into bars (bar, etc.). These highly desirable properties are based on nickel, 27 to 33 wt.% chromium, 4.9 to 7.8 wt.% molybdenum, under the clue that if chromium is less than 30 wt.%, copper should be at least 4.7 wt.%, And 3.1 wt.% to 6.0 wt.% of copper. For a chromium content of 30 to 33 wt.%, the full range of copper (3.1 to 6.0 wt.%) provides these highly desirable properties.

In order to enable the removal of oxygen and sulfur during the melting process, such alloys typically contain small amounts of aluminum and manganese (up to about 0.5 and 1.0 wt.% respectively in the nickel-chromium-molybdenum alloy), and possibly trace amounts of magnesium and It contains rare earth elements (up to about 0.05 wt.%). In the applicant's experiment, it was found that an aluminum content of 0.1 to 0.5 wt.%, and a manganese content of 0.3 to 1.0 wt.% yielded a successful alloy.

In such alloys iron is the most possible impurity due to contamination from other nickel alloys dissolved in the same furnace, and up to 2.0 or 3.0 wt.% of these nickel-chromium-molybdenum alloys are typical so no iron addition is required. In our experiment, it was found that iron content of up to 3.0 wt.% is acceptable.

Other metallic impurities are possible in such alloys due to furnace contamination and impurities in the input material. The alloys of the present invention must be able to tolerate the levels of these impurities commonly encountered in nickel-chromium-molybdenum alloys. In addition, such high chromium content alloys cannot be air soluble without obtaining some nitrogen. Therefore, it is common for high chromium nickel alloys to tolerate a maximum of 0.13 wt.% of these elements.

Regarding the carbon content, the successful alloys in Applicants' experiments contained 0.01 to 0.11 wt.%. Surprisingly, alloy G with a carbon content of 0.002 wt.% could not be machined into a forged product. Therefore, carbon in the range of 0.01 to 0.11 wt.% is preferred.

With regard to silicon, a range of 0.1 to 0.8 wt.% is preferred and is based on the fact that the levels at each end of the range provided satisfactory properties.

The microstructural stability of these alloys at elevated temperatures can be improved by promoting the formation of highly stable MC carbides.

The discovery of the composition ranges defined above involved the study of a wide range of nickel-based compositions of various chromium, molybdenum, and copper contents. These compositions are shown in Table 1. For comparison, the composition of commercially available alloys used to withstand 70% sulfuric acid or 50% sodium hydroxide is included in Table 1.

Table 1: Composition of Experimental and Commercial Alloys

* Indicates the alloy of the present invention, ** indicates the nominal composition

Experimental alloys were prepared with a heat size of 13.6 kg by vacuum induction melting method (VIM) followed by electro-slag re-dissolution method (ESR). Trace amounts of nickel-magnesium and/or rare earths were added to the VIM furnace input to help minimize the sulfur and oxygen content of the test alloys. The ESR ingots were homogenized, hot forged, and hot rolled into sheets of thickness 3.2 for testing. Unexpectedly, the three alloys (G, K, and L) cracked so badly during forging that they could not be hot rolled into sheets for testing. In order to determine the most appropriate annealing treatment (by metallurgical means), an annealing test was applied to the alloys that were successfully rolled to the required test thickness. 15 minutes at a temperature of 1121° C. to 1149° C., after which water quenching was determined to be appropriate in all cases. All commercially made alloys were tested under the conditions sold by the manufacturer, so-called "factory annealed".

Corrosion tests were performed on samples of size 25.4 x 25.4 x 3.2 mm. Prior to the corrosion test, the surfaces of all samples were manually ground using 120 grit paper to remove any surface films and defects that could affect the corrosion resistance. Testing in sulfuric acid was performed in a glass flask/condenser system. The tests in sodium hydroxide were carried out in the TEFLON system because the glass is damaged by sodium hydroxide. The sample was stopped every 24 hours so that it could be weighed, and a period of 96 hours was used for the sulfuric acid test, while a period of 720 hours was used for the sodium hydroxide test. Two samples of each alloy were tested in each environment, and the results were averaged.

In sulfuric acid, the main mode of decomposition is uniform damage, so the average corrosion rate was calculated from weight loss measurements. In sodium hydroxide, the main mode of decomposition is internal damage, either homogeneous damage or a more aggressive form of internal "dealloying" damage. Decomposition corrosion generally refers to the leaching of certain elements (eg molybdenum) from the alloy, which often also degrades mechanical properties. Maximum internal damage can only be determined by sectioning the sample and studying it metallurgically. The values presented in Table 2 represent the maximum internal penetration measured in the alloy cross-survey.

To make the difference between the permissible and unacceptable rates of damage, a good/bad criterion of 0.45 mm/y (of homogeneous damage in the case of sulfuric acid and maximum internal penetration in the case of sodium hydroxide) was used. Alloys with corrosion rates greater than 0.45 mm/y are considered unacceptable. The background of this criterion relates to the iso-corrosion diagrams used in industry to determine if alloys are tolerated or unacceptable at specific concentrations and temperatures of different chemicals. Several samples or test specimens of the considered alloy are tested and the corrosion rate for each test is plotted. Then, draw a line according to the data score. In these diagrams, a corrosion rate of 0.45 to 0.55 mm/y will often make a plot line of 0.5 mm/y to account for random and regular variations. In many applications, the art considers corrosion rates of less than 0.5 mm/y to be acceptable. However, since an alloy having a corrosion rate of 0.45 to 0.55 mm/y can be considered to have a corrosion rate of 0.5 mm/y, the inventors concluded that the corrosion rate should be less than 0.45 mm/y to be acceptable. , The performance requirements were set for the alloys of the present invention.

Table 2 shows the internal penetration rate corresponding to that the alloy of the present invention corrodes at a sufficiently low rate in 70% sulfuric acid for industrial use at 93° C., and significantly less than 0.5 mm/y in 50% sodium hydroxide at 121° C. Shows. Interestingly, unlike nickel-chromium-molybdenum alloys (C-4, C-22, C-276, and C-2000) with high molybdenum content, none of the alloys of the present invention is a deconstituent corrosion form of corrosion damage. Did not show. The required range of 3.1 to 6.0 wt.% copper, and if chromium is less than 30 wt.%, the clue that copper should be at least 4.7 wt.% results for various alloys, especially A, B, C, E, and N Is based on. The relationship between chromium and copper is possible due to their respective effects on the protective film at 70% sulfuric acid. For example, it is known that chromium causes a chromium-enriched film on the metal surface in oxidizing acids, and that copper can provide protection by applying the metal surface in concentrated sulfuric acid. Alloys K and L with higher copper content could not be forged.

The chromium range is based on the results for Alloys A and O (having contents of 27 and 33 wt.%, respectively). The molybdenum range is based on the results for alloys H and A (having a content of 4.9 and 7.8 wt.%, respectively), and the proposal of U.S. Patent No. 6,764,646 indicating a molybdenum content of less than 4.9 wt. It does not provide sufficient resistance to flank corrosion of molybdenum-copper alloys. This is important for neutralization systems containing other chemicals.

Unexpectedly, when iron, manganese, aluminum, silicon, and carbon were missing (alloy G), the alloy could not be forged. To further confirm the effect of iron, alloy P without deliberate iron addition was dissolved. The fact that Alloy P has been successfully hot forged and hot rolled indicates that the presence of manganese, aluminum, silicon, and carbon is critical to the successful processing of these alloys. In addition, the absence of iron in alloy P was not disadvantageous in terms of corrosion because the alloy showed excellent performance in both corrosive media.

Table 2: Corrosion test results for experimental and commercial alloys

* Indicates the alloy of the present invention

GC-front corrosion

Observations on the effects of alloying elements are as follows:

Chromium (Cr) is a major alloying element known to improve the performance of nickel alloys in oxidizing acids. When combined with molybdenum and copper (a special relationship applies here), chromium has been shown to provide desirable corrosion resistance for both 70% sulfuric acid and 50% sodium hydroxide in the range 27-33 wt.%.

Molybdenum (Mo) is also a major alloying element known to improve the corrosion resistance of nickel alloys in reducing acids. In the range of 4.9 to 7.8 wt.%, molybdenum contributes to the good performance of the alloys of the present invention in 70% sulfuric acid and 50% sodium hydroxide.

From 3.1 wt.% to 6.0 wt.%, and in combination with chromium and molybdenum at the above-mentioned levels, copper (Cu) was added to acids and alkalis in the form of 70% sulfuric acid at 93° C. and 50% sodium hydroxide at 121° C. It produces an alloy with unusual and unexpected resistance to

Iron (Fe) is a common impurity in nickel alloys. An iron content of up to 3.0 wt.% was found to be acceptable in the alloys of the present invention.

Manganese (Mn) is used to minimize sulfur in these alloys, and a content of 0.3 to 1.0 wt.% has been found to produce a successful alloy (from a processing and performance standpoint).

Aluminum (Al) is used to minimize oxygen in these alloys, and a content of 0.1 to 0.5 wt.% has been found to produce a successful alloy.

Silicon (Si) is usually not required in corrosion-resistant nickel alloys, but is introduced during argon-oxygen decarburization (for alloys dissolved in air). It has been found that small amounts of silicon (in the range of 0.1 to 0.8 wt.%) are essential for the alloys of the present invention to ensure forgeability.

Similarly, carbon (C) is usually not required in corrosion-resistant nickel alloys, but is introduced during carbon arc melting (for alloys dissolved in air). It has been found that a small amount of carbon (in the range of 0.01 to 0.11 wt.%) is essential for the alloys of the present invention to ensure forgeability.

Trace amounts of magnesium (Mg) and/or rare earth elements are often included in these alloys to control unwanted elements such as sulfur and oxygen. Thus, a general range of up to 0.05 wt.% is preferred for each of these elements in the inventive alloy.

Nitrogen (N) is readily absorbed by high chromium nickel alloys in the dissolved state, and in this kind of alloy it is common to allow up to 0.13 wt.% of these elements.

Other impurities that may appear in these alloys due to contamination from previously-used blast furnace interior walls or inside raw material inputs include cobalt, tungsten, sulfur, phosphorus, oxygen, and calcium.

If enhanced microstructural stability is desired at elevated temperatures (as may be experienced during welding or during elevated temperature service), deliberate, small additions of elements that promote the formation of MC carbides can be used. Such elements include titanium, niobium (columbium), hafnium, and tantalum. Other less preferred MC carbide formers that can be used are such as vanadium. MC carbides are much more stable than the M ₇ C ₃ , M ₆ C, and M ₂₃ C ₆ carbides commonly encountered in chromium- and molybdenum-containing nickel alloys. In fact, it should be possible to control the levels of these MC-forming elements in order to bind as much carbon as is considered adequate to control the level of carbide precipitation at the grain boundaries. In fact, the MC-former level could be fine-tuned during the melting process relying on real-time measurement of the carbon content.

If the alloy is used to withstand aqueous corrosion, the MC-former level can be tailored to the carbon level to prevent significant grain boundary carbide precipitation (so-called “stable” structure).

However, there are two possible problems. Firstly, nitrogen can compete with carbon to form nitrides or carbonitrides of the same active former (e.g. titanium), and therefore must be present at higher levels (this can be calculated based on real-time measurements of nitrogen content). have). The second is an unintended formation of a gamma-prime (with titanium) or gamma-double prime (with niobium); However, the cooling and post-processing sequence may be adjusted to ensure that these elements are bound in the form of carbides, nitrides, or carbonitrides.

For example, ignoring the nitrogen effect and using titanium, binding all carbon to MC carbides may require atomic parity. Since the atomic weight of titanium is approximately four times that of carbon (47.9 versus 12.0), this can be reflected in the weight percentage of the two elements. Thus, stable versions of these alloys for aqueous corrosion service may contain 0.05 wt.% carbon and 0.20 wt.% titanium. These alloys for elevated temperature service may contain 0.05 wt.% carbon and 0.15 wt.% titanium to allow for a controlled level of secondary, grain boundary precipitation to improve creep resistance. For nitrogen at an impurity level of eg 0.035 wt.%, an additional 0.12 wt.% titanium will be needed to bind this element (because the atomic weight of nitrogen is 14.0). Thus, for a carbon content of 0.05 wt.%, 0.32 wt.% titanium may be required for aqueous corrosion service and 0.27 wt.% titanium may be needed for elevated temperature service. Therefore, for a carbon level of 0.11 wt.%, and a nitrogen impurity level of 0.035 wt.%, 0.56 wt.% titanium may be required for aqueous corrosion services.

The atomic weights of niobium, hafnium, and tantalum are 92.9, 178.5, and 181.0, respectively. Thus, the niobium content required to obtain the same benefit is approximately twice that of titanium. The hafnium or tantalum content required to achieve the same benefit is approximately four times that of titanium.

Thus, for aqueous corrosion services, niobium-stable versions of these alloys have 0.05 wt.% carbon and 0.40 wt.% niobium (if the alloy does not contain any nitrogen), and a nitrogen impurity level of 0.035 wt.%. In some cases, it may contain 0.64 wt.% niobium. For a carbon level of 0.11 wt.%, and a nitrogen impurity level of 0.035 wt.%, 1.12 wt.% niobium may be required for aqueous corrosion services. Alloys for elevated temperature service may contain 0.05 wt.% carbon and 0.30 wt.% niobium, in the absence of nitrogen impurities.

Similarly, for aqueous corrosion services, the hafnium-stable versions of these alloys contain 0.05 wt.% carbon and 0.80 wt.% hafnium (if the alloy does not contain any nitrogen), and if the nitrogen impurity level is 0.035 wt.%. May contain 1.28 wt.% hafnium. For a carbon level of 0.11 wt.%, and a nitrogen impurity level of 0.035 wt.%, 2.24 wt.% hafnium may be required for aqueous corrosion services. Alloys for elevated temperature service may contain 0.05 wt.% carbon and 0.60 wt.% hafnium, in the absence of nitrogen impurities.

Similarly, for aqueous corrosion services, tantalum-stable versions of these alloys have 0.05 wt.% carbon and 0.80 wt.% tantalum (if the alloy does not contain any nitrogen), and a nitrogen impurity level of 0.035 wt.%. In some cases, it may contain 1.28 wt.% tantalum. For a carbon level of 0.11 wt.%, and a nitrogen impurity level of 0.035 wt.%, 2.24 wt.% tantalum may be required for aqueous corrosion services. Alloys for elevated temperature service may contain 0.05 wt.% carbon and 0.60 wt.% tantalum, in the absence of nitrogen impurities.

Prior art for other high-chromium nickel alloys (US Pat. No. 6,740,291, Crook) allows impurity levels of cobalt and tungsten in this kind of alloy to be tolerated at levels of up to 5 wt.% and 0.65 wt.%, respectively. Tells you. Permissible impurity levels for sulfur (up to 0.015 wt.%), phosphorus (up to 0.03 wt.%), oxygen (up to 0.05 wt.%), and calcium (up to 0.05 wt.%) are specified in U.S. Patent No. 6,740,291 Has been. These impurity limits are considered appropriate for the alloys of the present invention.

Although the samples tested were in the form of a forged sheet, the alloy should exhibit properties comparable to other forged forms, such as plates, bars, tubes, and wires, and to cast and powder metallurgical forms. Further, the alloys of the present invention are not limited to applications involving neutralization of acids and alkalis. In fact, they may have a much wider range of applications in the chemical process industry and, given their high chromium and copper presence, would be useful in withstanding metal dusting.

Considering the desire to maximize the corrosion resistance of these alloys, the ideal alloy is 31 wt.% chromium, 5.6 wt.% molybdenum, 3.8 wt.% copper, while optimizing their microstructural stability (thus facilitating the forging process). 1.0 wt.% iron, 0.5 wt.% manganese, 0.3 wt.% aluminum, 0.4 wt.% silicon, and 0.03 to 0.07 wt.% carbon, and nickel, nitrogen, impurities, and trace amounts of magnesium and (sulfur and oxygen If used for control) it is expected to contain the balance of rare earth elements. This alloy composition may also contain at least one MC carbide former selected from the group consisting of titanium, niobium, tantalum and hafnium. When present in this alloy, the alloy contains 0.20 to 0.56 wt.% titanium, 0.30 to 1.12 wt.% niobium, 0.60 to 2.24 wt.% tantalum and/or 0.60 to 2.24 wt.% hafnium. In fact, two alloys, Q and R, of this preferred nominal composition, have been successfully dissolved, hot forged and rolled into sheets. As shown in Table 2, alloys Q and R both showed good corrosion resistance in the selected corrosive medium. Moreover, with this desired nominal composition, the production scale hits (13,608 kg) of Alloy S were successfully dissolved and rolled, thereby confirming that the alloy had excellent formability. The alloy also has desirable corrosion properties at 70% sulfuric acid and 50% sodium hydroxide at 121°C. Corresponding ranges (typical in steel mill practice) are 30 to 33 wt.% chromium, 5.0 to 6.2 wt.% molybdenum, 3.5 to 4.0 wt.% copper, up to 1.5 wt.% iron, 0.3 to 0.7 wt.% manganese, 0.1 to 0.4 wt.% aluminum, 0.1 to 0.6 wt.% silicon, and 0.02 to 0.10 wt.% carbon, and nickel, nitrogen, impurities, and trace amounts of magnesium and rare earths (if used for the control of sulfur and oxygen) It can be the balance of.

Claims (14)

Consisting of, it has a corrosion rate of less than 0.5 mm/y in 70% sulfuric acid at 93°C and is resistant to sulfuric acid, has an internal penetration rate of less than 0.5 mm/y in 50% sodium hydroxide at 121°C and is resistant to sodium hydroxide. Nickel-chromium-molybdenum-copper alloy:
27 to 33 wt.% chromium
4.9 to 7.8 wt.% molybdenum
3.5 wt.% to 6.0 wt.% copper
Up to 3.0 wt.% iron
0.3 to 1.0 wt.% manganese
0.1 to 0.5 wt.% aluminum
0.1 to 0.8 wt.% silicon
0.01 to 0.11 wt.% carbon
0.13 wt.% nitrogen
Up to 0.05 wt.% magnesium
Up to 0.05 wt.% rare earth elements
0.56 wt.% titanium
1.12 wt.% niobium max
Up to 2.24 wt.% tantalum
Up to 2.24 wt.% hafnium
Up to 0.015 wt.% sulfur
Up to 5 wt.% cobalt
Up to 0.65 wt.% tungsten
0.03 wt.% phosphorus
0.05 wt.% oxygen max
0.05 wt.% calcium max
And balance of nickel and impurities. The nickel-chromium-molybdenum-copper alloy of claim 1, wherein the impurity comprises at least one level of cobalt, tungsten, sulfur, phosphorus, oxygen and calcium. The nickel-chromium-molybdenum-copper alloy according to claim 1, wherein the alloy is in a forged form selected from the group consisting of sheet, plate, bar, wire, tube, pipe, and forging. The nickel-chromium-molybdenum-copper alloy according to claim 1, wherein the alloy is in a cast form. The nickel-chromium-molybdenum-copper alloy according to claim 1, wherein the alloy is in powder metallurgical form. The nickel-chromium-molybdenum-copper alloy according to claim 1 consisting of:
30 to 33 wt.% chromium
5.0 to 6.2 wt.% molybdenum
3.5 to 4.0 wt.% copper
Up to 1.5 wt.% iron
0.3 to 0.7 wt.% manganese
0.1 to 0.4 wt.% aluminum
0.1 to 0.6 wt.% silicon
0.02 to 0.10 wt.% carbon
And balance of nickel and impurities. The nickel-chromium-molybdenum-copper alloy according to claim 1 consisting of:
31 wt.% chromium
5.6 wt.% molybdenum
3.8 wt.% copper
1.0 wt.% iron
0.5 wt.% manganese
0.4 wt.% silicon
0.3 wt.% aluminum
0.03 to 0.07 wt.% carbon
Magnesium up to 0.05 wt.%
And balance of nickel and impurities. The nickel-chromium-molybdenum-copper alloy according to claim 1 consisting of:
31 wt.% chromium
5.6 wt.% molybdenum
3.8 wt.% copper
1.0 wt.% iron
0.5 wt.% manganese
0.4 wt.% silicon
0.3 wt.% aluminum
0.03 to 0.07 wt.% carbon
Up to 0.05 wt.% magnesium, up to 0.05 wt.% rare earth elements
And balance of nickel and impurities The nickel-chromium-molybdenum-copper alloy according to claim 1, wherein the alloy contains at least one MC carbide former selected from the group consisting of titanium, niobium, tantalum and hafnium. The nickel-chromium-molybdenum-copper alloy according to claim 1, wherein the alloy contains 0.20 to 0.56 wt.% titanium. The nickel-chromium-molybdenum-copper alloy according to claim 1, wherein the alloy contains 0.30 to 1.12 wt.% niobium. The nickel-chromium-molybdenum-copper alloy according to claim 1, wherein the alloy contains 0.60 to 2.24 wt.% tantalum. The nickel-chromium-molybdenum-copper alloy according to claim 1, wherein the alloy contains 0.60 to 2.24 wt.% hafnium. delete