CA2291051A1 - Nickel-chromium-molybdenum alloy - Google Patents
Nickel-chromium-molybdenum alloy Download PDFInfo
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- CA2291051A1 CA2291051A1 CA002291051A CA2291051A CA2291051A1 CA 2291051 A1 CA2291051 A1 CA 2291051A1 CA 002291051 A CA002291051 A CA 002291051A CA 2291051 A CA2291051 A CA 2291051A CA 2291051 A1 CA2291051 A1 CA 2291051A1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/03—Alloys based on nickel or cobalt based on nickel
- C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
- C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
- C22C19/055—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being at least 20% but less than 30%
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/03—Alloys based on nickel or cobalt based on nickel
- C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3033—Ni as the principal constituent
- B23K35/304—Ni as the principal constituent with Cr as the next major constituent
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Abstract
The invention relates to a kneadable, homogeneous, austenitic nickel alloy having a high corrosion resistance in relation to aggressive media under both oxidating and reducing conditions, excellent resistance to local corrosion in acid chloride-containing media and high structural stability following thermal stress. Said alloy consists of the following ( % by mass): chromium 20.0 to 23.0 %, molybdenum 18.5 to 21.0 %, iron max. 1.5 %, manganese max. 0.5 %, silicon max. 0.10 %, cobalt max. 0.3 %, wolfram max. 0.3 %, copper max. 0.3 %, aluminium 0.1 to 0.3 %, magnesium 0.001 to 0.015 %, calcium 0.001 to 0.010 %, carbon max. 0.01 %, nitrogen 0.05 to 0.15 %, vanadium 0.1 to 0.3 %, with the rest consisting of nickel and other impurities resulting from the melting process. Said alloy is a suitable material for objects resistant to chemical attack and as super-alloyed solder for other nickel-based materials.
Description
FILE, P'~'~' T~I5 Aidi~~'B' ~R~,~SLATIOIJ
Nickel-Chromium-Molvbdenum Allo The present invention relates to an austenitic nickel-chromium-molybdenum alloy having a high corrosion resistance in relation to oxidizing and reducing media.
As a rule, austenitic nickel alloys, which display outstanding resistance to reducing media such as hydrochloric acid, are alloyed with 26 to 30% molybdenum. Examples of known nickel-1o molybdenum alloys are Alloy B-2 (2.4617) and Alloy B-4 (2.4600).
These alloys are resistant to hydrochloric acid up to the boiling point providing that there are no traces of oxidizing components such as Fe3+ in the acid. Such traces can, however, be introduced very easily as impurities as the acid is being transported. In a similar way, the presence of traces of HN03 causes a sharp increase in the corrosion rate of nickel-molybdenum alloys. For this reason, there has been no lack of attempts to render quasi-binary nickel-molybdenum alloys immune to oxidizing impurities by modification of their composition.
2o As an example, EP 0 723 029 A1 describes a nickel-molybdenum-chromium-iron alloy that possesses outstanding resistance to corrosion in relation to acid, lower-oxygen media.
This has been achieved in that on the average, the molybdenum content was cut back to 23% and in that, in contrast to this, the material was alloyed, on the average, with about 8% chromium.
On the other hand, corrosion-resistant nickel alloys with chromium and molybdenum as the principal alloying components are also known, these containing 14 to 26% chromium and 3 to 18%
molybdenum or 20 to 24% chromium, 12 to 17% molybdenum, 2 to 4%
tungsten, and 2 to 8% iron.
According to EP 0 334 410 B1, an alloy with 22 to 24%
chromium and 15 to 16.5% molybdenum can be used advantageously for the working conditions of chemical process technology and environmental protection technology. According to their topical to composition, these materials possess good resistance to eroding corrosion and against pitting and fissure corrosion. Because of their high chromium content, however, their resistance under reducing conditions is not as good as in oxidizing media. Attempts have been made to correct this deficiency in that some 2 to 4%
tungsten is added to an alloy with about 19 to 23% chromium and about 14 to 17% molybdenum.
One disadvantage to alloys of such composition is that they require a special homogenizing-annealing treatment, as is described in detail in European Patent Application EP 0 392 484 A1.
2o In addition, this alloy possesses low thermal stability, which is a disadvantage when it has to be processed, for example by welding.
This is made clear by the results tabulated below, which show corrosion loss in mm/year in a standard test of inter-crystalline corrosion according to ASTM G 28 A, whereby a typical alloy composition according to EP 0 392 484 A1 is checked, once in the . solution-annealed state and once in a thermally stressed state for 1 hour at 870~C. In one case, corrosion loss was 2.63 mm/year and in the other case it was 22.14 mm/year. One can recognize the low stability in relation to thermal stress in that the 1-hour change at 870~C causes corrosion loss in the standard test according to ASTM G-28 A to increase by a factor of more than 8 in the case of the alloy according to EP 0 392 484 Al. Alternatively, European Patent Application EP 0 693 565 A2 proposes a nickel-chromium-molybdenum alloy in which--amongst others--1.0 to 3.5% copper is 1o alloyed in with 22.0 to 24.50 chromium and 14.0 to 18.0%
molybdenum. Nitrogen in amounts of up to 0.150 can be added to this combination as a strength-enhancing element, although it is preferred that no more than 0.06% be added, because according to the teachings of EP 0 693 565 A2 nitrogen in this alloying combination with copper is detrimental to corrosion resistance in hydrochloric acid, the typical reducing medium. Besides, the addition of copper diminishes thermal stability, which is a disadvantage from the standpoint of processing, for example by welding. This is shown clearly by the results set out below, which 2o were obtained once as corrosion loss in mm/year in the standard test for intercrystalline corrosion according to ASTM G-28 A, whereby a typical alloying composition according to EP 0693 565 A 2 was tested once in the solution-annealed state and once in an altered state after 1 hour at 870~C. In one case, corrosion loss was 0.68 mm/year and in the other case it was 2.90 mm/year.
Nickel-Chromium-Molvbdenum Allo The present invention relates to an austenitic nickel-chromium-molybdenum alloy having a high corrosion resistance in relation to oxidizing and reducing media.
As a rule, austenitic nickel alloys, which display outstanding resistance to reducing media such as hydrochloric acid, are alloyed with 26 to 30% molybdenum. Examples of known nickel-1o molybdenum alloys are Alloy B-2 (2.4617) and Alloy B-4 (2.4600).
These alloys are resistant to hydrochloric acid up to the boiling point providing that there are no traces of oxidizing components such as Fe3+ in the acid. Such traces can, however, be introduced very easily as impurities as the acid is being transported. In a similar way, the presence of traces of HN03 causes a sharp increase in the corrosion rate of nickel-molybdenum alloys. For this reason, there has been no lack of attempts to render quasi-binary nickel-molybdenum alloys immune to oxidizing impurities by modification of their composition.
2o As an example, EP 0 723 029 A1 describes a nickel-molybdenum-chromium-iron alloy that possesses outstanding resistance to corrosion in relation to acid, lower-oxygen media.
This has been achieved in that on the average, the molybdenum content was cut back to 23% and in that, in contrast to this, the material was alloyed, on the average, with about 8% chromium.
On the other hand, corrosion-resistant nickel alloys with chromium and molybdenum as the principal alloying components are also known, these containing 14 to 26% chromium and 3 to 18%
molybdenum or 20 to 24% chromium, 12 to 17% molybdenum, 2 to 4%
tungsten, and 2 to 8% iron.
According to EP 0 334 410 B1, an alloy with 22 to 24%
chromium and 15 to 16.5% molybdenum can be used advantageously for the working conditions of chemical process technology and environmental protection technology. According to their topical to composition, these materials possess good resistance to eroding corrosion and against pitting and fissure corrosion. Because of their high chromium content, however, their resistance under reducing conditions is not as good as in oxidizing media. Attempts have been made to correct this deficiency in that some 2 to 4%
tungsten is added to an alloy with about 19 to 23% chromium and about 14 to 17% molybdenum.
One disadvantage to alloys of such composition is that they require a special homogenizing-annealing treatment, as is described in detail in European Patent Application EP 0 392 484 A1.
2o In addition, this alloy possesses low thermal stability, which is a disadvantage when it has to be processed, for example by welding.
This is made clear by the results tabulated below, which show corrosion loss in mm/year in a standard test of inter-crystalline corrosion according to ASTM G 28 A, whereby a typical alloy composition according to EP 0 392 484 A1 is checked, once in the . solution-annealed state and once in a thermally stressed state for 1 hour at 870~C. In one case, corrosion loss was 2.63 mm/year and in the other case it was 22.14 mm/year. One can recognize the low stability in relation to thermal stress in that the 1-hour change at 870~C causes corrosion loss in the standard test according to ASTM G-28 A to increase by a factor of more than 8 in the case of the alloy according to EP 0 392 484 Al. Alternatively, European Patent Application EP 0 693 565 A2 proposes a nickel-chromium-molybdenum alloy in which--amongst others--1.0 to 3.5% copper is 1o alloyed in with 22.0 to 24.50 chromium and 14.0 to 18.0%
molybdenum. Nitrogen in amounts of up to 0.150 can be added to this combination as a strength-enhancing element, although it is preferred that no more than 0.06% be added, because according to the teachings of EP 0 693 565 A2 nitrogen in this alloying combination with copper is detrimental to corrosion resistance in hydrochloric acid, the typical reducing medium. Besides, the addition of copper diminishes thermal stability, which is a disadvantage from the standpoint of processing, for example by welding. This is shown clearly by the results set out below, which 2o were obtained once as corrosion loss in mm/year in the standard test for intercrystalline corrosion according to ASTM G-28 A, whereby a typical alloying composition according to EP 0693 565 A 2 was tested once in the solution-annealed state and once in an altered state after 1 hour at 870~C. In one case, corrosion loss was 0.68 mm/year and in the other case it was 2.90 mm/year.
One can recognize the low stability in relation to thermal stress in that the 1-hour change at 870~C causes corrosion loss to increase by a factor of more than 4.
The low thermal stability of this alloy is even more clearly seen if it is tested once in the solution-annealed state and once in the altered state after 1 hour at 870°C in the alternative standard test for intercrystalline corrosion according to ASTM G-28 B. Corrosion losses of 0.11 and 57.8 mm/year are then seen, which is to say it is increased by more than 500-fold by one-to hour aging, when the corrosive attack was so powerful along the grain borders that complete grains fell out of the material during the test.
In addition, the use of a nickel-chromium-molybdenum alloy with 20% chromium, 20% molybdenum, and 2o tantalum for heat-exchanger tubes to recover heat from the flue gasses of power stations fired by fossil fuels is also known. According to CORROSION 96, Paper No. 413, this alloy is reputed to be particularly suitable for withstanding the dew-point corrosion of the sulphuric acid that occurs in this application. Because of the 2o composition of the alloy, its thermal stability is estimated to be no better than that of the two alloys according to EP 0 392 484 Al and EP 0 693 565 A2 discussed heretofore.
This results in the task of describing a nickel-chromium-molybdenum alloy that has a balanced corrosion resistance in a number of both oxidizing and reducing media, whereby it is superior to the prior art, but without the disadvantage that, on the one hand, it requires a special homo-agenizing-annealing treatment and, on the other, without he disadvantage of low thermal stability.
t According to the present invention, this has been achieved with a nickel-chromium-molybdenum alloy of the following composition (o by mass) Chromium 20.0 to 23.0%
Molybdenum 18.5 to 2l.Oo Iron max. 1.50 1o Manganese max. 0.50 Silicon max. O.lOo Cobalt max. 0.3%
Tungsten max. 0.3%
Copper max. 0.30 Aluminum 0.1 to 0.3%
Magnesium 0.001 to 0.015%
Calcium 0.001 to 0.010%
Carbon max. 0.01%
Nitrogen 0.05 to 0.15%
2o Vanadium 0.1 to 0.3%
the rest consisting of nickel and impurities resulting from the melting process.
A preferred nickel-chromium-molybdenum alloy contains the following composition (% by mass):
Chromium 20.5 to 21.50 Molybdenum 19.5 to 20.5%
Iron max. 1.5%
Manganese max. 0.5%
Silicon max. 0.10%
s Cobalt max. 0.3%
Tungsten max. 0.3%
Copper max. 0.3%
Aluminum 0.1 to 0.3%
Magnesium 0.001 to 0.015%
1o Calcium 0.001 to 0.010%
Carbon max. 0.01%
Nitrogen 0.08 to 0.12%
the rest consisting of nickel and impurities resulting from the melting process.
15 According to another concept of the present invention, the following additives (% by mass) can be alloyed with the one or the other nickel-chromium-molybdenum alloy:
Boron max. 0.0030%
Phosphorous max. 0.020%
2o Sulphur max. 0.010%
Niobium max. 0.20%
Titanium max. 0.02%
A preferred area of application for the object of the present invention can be seen in the fact that the nickel-chromium-25 molybdenum alloy is used in chemical plants for structural elements that must be highly resistant to oxidizing and to reducing media at one and the same time.
It is also possible to use the alloy according to the present invention as a welding filler for super-alloyed welding of highly alloyed NiCrMo materials and as a welding filler of the same type, with little segregation, with itself.
An alloy that is of especially universal use has a chromium:molybdenum ratio between 1.9 and 2.3, as calculated in substance content based on % by atoms, with a ratio of to approximately 2.0 being considered as the optimal.
Most surprisingly, it has been shown that in the case of this alloy composition of, on average for example, approximately 21o chromium and 20o molybdenum it is possible to so broaden the nickel-chromium-molybdenum three-substance system such that is approximately present here, that--on the one hand-- the substance requires no homogenizing-annealing treatment but--on the other hand--the corrosion resistance remains unimpaired in reducing media such as hydrochloric acid, which would have to be anticipated here, too, according to the prior art described heretofore.
2o The present invention will now be described in comparison to the known nickel alloys according to the prior art.
At the designations 1, 2, and 3, Table 1 shows embodiments of the alloy according to the present invention. These three embodiments were smelted in the usual manner in an induction oven and processed into 5 and 12-mm thick plates, in conformity _7_ . with the standard production methods for nickel-based materials.
As can be seen from Table 1, the comparison materials that correspond to the prior art all have nitrogen contents that are clearly below 0.040.
Table 2 shows the test results for the three embodiments of the alloy according to the present invention, as well as for comparison materials for two oxidizing test solutions of different strengths (ASTM G 28 A and B), as well as two reducing test media (SEP 1877 III and DuPont SW 800 M). As expected, the high mol content variants Alloy B-2/B-4 and B-10 are not resistant to corrosion under these oxidizing conditions. Even in the weaker oxidizing solution of the ASTM G 28 B test, these materials display even more pronounced intercrystalline corrosion and decompose actively. In contrast to this, the embodiments of the alloy according to the present invention are distinguished both in the oxidizing and in the reducing media by resistance to intercrystalline corrosion and exhibit the lowest overall mass loss rates for both media ranges. Embodiment 2 of the alloy according to the present invention, which has a Cr:Mo ratio that is slightly less than 2, is distinguished by particularly low rates of corrosion when examined in this way.
This is made clear in Table 3, that presents the results of testing the embodiments of the alloy according to the present invention and the comparison materials as total values of the measured corrosion loss in tests conducted under oxidizing and _g-. under reducing conditions, as set out in Table 2. Alloy 1, with 18.6% molybdenum is just above the value according to the present invention, although it has properties that are better than the known prior art according to C-2000. This indicates that such an alloy can be used to better effect for certain applications.
As can be seen from Table 4, in another part of the test, the behaviour of the materials was determined in 2-% boiling hydrochloric acid. Under these conditions, the corrosion rate of the three embodiments of the alloy according to the present to invention is at the level found for the nickel-molybdenum alloys groups of materials--the so-called B alloys--and is clearly below the other comparison materials that correspond to the prior art. A
higher value is also cited for the alloy NiCr20-Mo20Ta (Corrosion 96, Paper No. 413).
A test medium that occupies a position mid-way between oxidizing and reducing conditions is represented by the test in 90%
sulphuric acid. As is shown by Table 5, the embodiments 1 to 3 of the alloy according to the present invention are extremely resistant to corrosion under these conditions. In particular, the 2o alloy variation No. 2, that has a Cr:Mo ratio of just under 2 exhibits resistance to corrosion that is at the level of the B-allot's.
The excellent resistance to local corrosion of embodiments 1 to 3 of the alloy according to the present invention when in an acid medium that contains chloride could be proven by testing in "Gruner Tod" [Green Death] medium. According to Table 6, the material Alloy 59 according to the prior art exhibits excellent resistance to corrosion. In "Gruner Tod" test medium, the critical pitting temperature is 125~C. In contrast to this, under these conditions, no pitting could be identified in the samples according to the present invention, even at 135°C. The alloys from the group of B-materials are not resistant in this test medium. The three embodiments of the new alloys according to the present invention exhibit the best behaviour.
1o Despite the high alloy shares, the test alloys exhibit structural stability that is superior to that of the comparison materials. As is made clear by Table 7, samples were sensibi-lized for 1 hour and 3 hours at 870~C and then subjected to testing according to ASTM G 28 B. After thermal stressing, the comparison materials C-276, C-22, 686, and C-2000 exhibit not only a sharp increase of corrosion rate, but also exhibit inter-crystalline corrosion to such a degree that individual grains fall out. In contrast to this, the materials according to the present invention were free of any manifestations of local corrosion, and were 2o distinguished by a particularly low rate of mass loss. It is true that in this test, only alloy 59 exhibited better behaviour, although under the "Gruner Tod" test conditions (Table 6) and in 90-o sulphuric acid (Table 5) and in 2-o hydro-chloric acid, as well as in the overview according to Table 3 it is less resistant to corrosion.
Table 8 combines the results of testing of the mechanical properties of the three embodiments of the alloy according to the present invention, and compares them to typical values for the comparison materials for the identical range of dimensions. It can be seen that in comparison to the alloys forming the prior art, the mechanical properties are not affected detrimentally.
Table 9 shows a comparison of the upper and the lower limiting values on the one hand of chromium and, on the other hand, of molybdenum. In each instance, the data are cited in by mass and 1o in o by atoms. Based on the lower and upper limiting values cited in Claim 1, the Cr:Mo ratio is between 1.99 and 2.02 (calculated as o by atoms)
The low thermal stability of this alloy is even more clearly seen if it is tested once in the solution-annealed state and once in the altered state after 1 hour at 870°C in the alternative standard test for intercrystalline corrosion according to ASTM G-28 B. Corrosion losses of 0.11 and 57.8 mm/year are then seen, which is to say it is increased by more than 500-fold by one-to hour aging, when the corrosive attack was so powerful along the grain borders that complete grains fell out of the material during the test.
In addition, the use of a nickel-chromium-molybdenum alloy with 20% chromium, 20% molybdenum, and 2o tantalum for heat-exchanger tubes to recover heat from the flue gasses of power stations fired by fossil fuels is also known. According to CORROSION 96, Paper No. 413, this alloy is reputed to be particularly suitable for withstanding the dew-point corrosion of the sulphuric acid that occurs in this application. Because of the 2o composition of the alloy, its thermal stability is estimated to be no better than that of the two alloys according to EP 0 392 484 Al and EP 0 693 565 A2 discussed heretofore.
This results in the task of describing a nickel-chromium-molybdenum alloy that has a balanced corrosion resistance in a number of both oxidizing and reducing media, whereby it is superior to the prior art, but without the disadvantage that, on the one hand, it requires a special homo-agenizing-annealing treatment and, on the other, without he disadvantage of low thermal stability.
t According to the present invention, this has been achieved with a nickel-chromium-molybdenum alloy of the following composition (o by mass) Chromium 20.0 to 23.0%
Molybdenum 18.5 to 2l.Oo Iron max. 1.50 1o Manganese max. 0.50 Silicon max. O.lOo Cobalt max. 0.3%
Tungsten max. 0.3%
Copper max. 0.30 Aluminum 0.1 to 0.3%
Magnesium 0.001 to 0.015%
Calcium 0.001 to 0.010%
Carbon max. 0.01%
Nitrogen 0.05 to 0.15%
2o Vanadium 0.1 to 0.3%
the rest consisting of nickel and impurities resulting from the melting process.
A preferred nickel-chromium-molybdenum alloy contains the following composition (% by mass):
Chromium 20.5 to 21.50 Molybdenum 19.5 to 20.5%
Iron max. 1.5%
Manganese max. 0.5%
Silicon max. 0.10%
s Cobalt max. 0.3%
Tungsten max. 0.3%
Copper max. 0.3%
Aluminum 0.1 to 0.3%
Magnesium 0.001 to 0.015%
1o Calcium 0.001 to 0.010%
Carbon max. 0.01%
Nitrogen 0.08 to 0.12%
the rest consisting of nickel and impurities resulting from the melting process.
15 According to another concept of the present invention, the following additives (% by mass) can be alloyed with the one or the other nickel-chromium-molybdenum alloy:
Boron max. 0.0030%
Phosphorous max. 0.020%
2o Sulphur max. 0.010%
Niobium max. 0.20%
Titanium max. 0.02%
A preferred area of application for the object of the present invention can be seen in the fact that the nickel-chromium-25 molybdenum alloy is used in chemical plants for structural elements that must be highly resistant to oxidizing and to reducing media at one and the same time.
It is also possible to use the alloy according to the present invention as a welding filler for super-alloyed welding of highly alloyed NiCrMo materials and as a welding filler of the same type, with little segregation, with itself.
An alloy that is of especially universal use has a chromium:molybdenum ratio between 1.9 and 2.3, as calculated in substance content based on % by atoms, with a ratio of to approximately 2.0 being considered as the optimal.
Most surprisingly, it has been shown that in the case of this alloy composition of, on average for example, approximately 21o chromium and 20o molybdenum it is possible to so broaden the nickel-chromium-molybdenum three-substance system such that is approximately present here, that--on the one hand-- the substance requires no homogenizing-annealing treatment but--on the other hand--the corrosion resistance remains unimpaired in reducing media such as hydrochloric acid, which would have to be anticipated here, too, according to the prior art described heretofore.
2o The present invention will now be described in comparison to the known nickel alloys according to the prior art.
At the designations 1, 2, and 3, Table 1 shows embodiments of the alloy according to the present invention. These three embodiments were smelted in the usual manner in an induction oven and processed into 5 and 12-mm thick plates, in conformity _7_ . with the standard production methods for nickel-based materials.
As can be seen from Table 1, the comparison materials that correspond to the prior art all have nitrogen contents that are clearly below 0.040.
Table 2 shows the test results for the three embodiments of the alloy according to the present invention, as well as for comparison materials for two oxidizing test solutions of different strengths (ASTM G 28 A and B), as well as two reducing test media (SEP 1877 III and DuPont SW 800 M). As expected, the high mol content variants Alloy B-2/B-4 and B-10 are not resistant to corrosion under these oxidizing conditions. Even in the weaker oxidizing solution of the ASTM G 28 B test, these materials display even more pronounced intercrystalline corrosion and decompose actively. In contrast to this, the embodiments of the alloy according to the present invention are distinguished both in the oxidizing and in the reducing media by resistance to intercrystalline corrosion and exhibit the lowest overall mass loss rates for both media ranges. Embodiment 2 of the alloy according to the present invention, which has a Cr:Mo ratio that is slightly less than 2, is distinguished by particularly low rates of corrosion when examined in this way.
This is made clear in Table 3, that presents the results of testing the embodiments of the alloy according to the present invention and the comparison materials as total values of the measured corrosion loss in tests conducted under oxidizing and _g-. under reducing conditions, as set out in Table 2. Alloy 1, with 18.6% molybdenum is just above the value according to the present invention, although it has properties that are better than the known prior art according to C-2000. This indicates that such an alloy can be used to better effect for certain applications.
As can be seen from Table 4, in another part of the test, the behaviour of the materials was determined in 2-% boiling hydrochloric acid. Under these conditions, the corrosion rate of the three embodiments of the alloy according to the present to invention is at the level found for the nickel-molybdenum alloys groups of materials--the so-called B alloys--and is clearly below the other comparison materials that correspond to the prior art. A
higher value is also cited for the alloy NiCr20-Mo20Ta (Corrosion 96, Paper No. 413).
A test medium that occupies a position mid-way between oxidizing and reducing conditions is represented by the test in 90%
sulphuric acid. As is shown by Table 5, the embodiments 1 to 3 of the alloy according to the present invention are extremely resistant to corrosion under these conditions. In particular, the 2o alloy variation No. 2, that has a Cr:Mo ratio of just under 2 exhibits resistance to corrosion that is at the level of the B-allot's.
The excellent resistance to local corrosion of embodiments 1 to 3 of the alloy according to the present invention when in an acid medium that contains chloride could be proven by testing in "Gruner Tod" [Green Death] medium. According to Table 6, the material Alloy 59 according to the prior art exhibits excellent resistance to corrosion. In "Gruner Tod" test medium, the critical pitting temperature is 125~C. In contrast to this, under these conditions, no pitting could be identified in the samples according to the present invention, even at 135°C. The alloys from the group of B-materials are not resistant in this test medium. The three embodiments of the new alloys according to the present invention exhibit the best behaviour.
1o Despite the high alloy shares, the test alloys exhibit structural stability that is superior to that of the comparison materials. As is made clear by Table 7, samples were sensibi-lized for 1 hour and 3 hours at 870~C and then subjected to testing according to ASTM G 28 B. After thermal stressing, the comparison materials C-276, C-22, 686, and C-2000 exhibit not only a sharp increase of corrosion rate, but also exhibit inter-crystalline corrosion to such a degree that individual grains fall out. In contrast to this, the materials according to the present invention were free of any manifestations of local corrosion, and were 2o distinguished by a particularly low rate of mass loss. It is true that in this test, only alloy 59 exhibited better behaviour, although under the "Gruner Tod" test conditions (Table 6) and in 90-o sulphuric acid (Table 5) and in 2-o hydro-chloric acid, as well as in the overview according to Table 3 it is less resistant to corrosion.
Table 8 combines the results of testing of the mechanical properties of the three embodiments of the alloy according to the present invention, and compares them to typical values for the comparison materials for the identical range of dimensions. It can be seen that in comparison to the alloys forming the prior art, the mechanical properties are not affected detrimentally.
Table 9 shows a comparison of the upper and the lower limiting values on the one hand of chromium and, on the other hand, of molybdenum. In each instance, the data are cited in by mass and 1o in o by atoms. Based on the lower and upper limiting values cited in Claim 1, the Cr:Mo ratio is between 1.99 and 2.02 (calculated as o by atoms)
Claims (6)
1. Austenitic nickel-chromium molybdenum alloy with a high corrosion resistance in relation to oxidizing and reducing conditions, comprising the following composition (% by mass):
Chromium ~~~~20.0 to 23.0%
Molybdenum ~~~~18.5 to 21.0%
Iron max. ~~~~1.5%
Manganese ~ max. 0.5%
Silicon ~~max. 0.10%
Cobalt ~~max. 0.3%
Tungsten ~~max. 0.3%
Copper ~~max. 0.3%
Aluminum ~~0.1 to 0.3%
Magnesium ~~0.001 to 0.015%
Calcium ~~0.001 to 0.010%
Carbon ~~max. 0.01%
Nitrogen ~~0.05 to 0.15%
Vanadium ~~0.1 to 0.3%
the rest consisting of nickel and impurities resulting from the melting process.
Chromium ~~~~20.0 to 23.0%
Molybdenum ~~~~18.5 to 21.0%
Iron max. ~~~~1.5%
Manganese ~ max. 0.5%
Silicon ~~max. 0.10%
Cobalt ~~max. 0.3%
Tungsten ~~max. 0.3%
Copper ~~max. 0.3%
Aluminum ~~0.1 to 0.3%
Magnesium ~~0.001 to 0.015%
Calcium ~~0.001 to 0.010%
Carbon ~~max. 0.01%
Nitrogen ~~0.05 to 0.15%
Vanadium ~~0.1 to 0.3%
the rest consisting of nickel and impurities resulting from the melting process.
2. Nickel-chromium molybdenum alloy as defined in Claim 1, characterized by the following composition (% by mass) Chromium 20.5 to 21.50 Molybdenum 19.5 to 20.5%
Iron max. 1.5%
Manganese max. 0.5%
Silicon max. 0.10%
Cobalt max. 0.3%
Tungsten max. 0.3%
Copper max. 0.3%
Aluminum 0.1 to 0.3%
Magnesium 0.001 to 0.015 Calcium 0.001 to 0.015%
Carbon max. 0.01%
Nitrogen 0.08 to 0.12%
the rest consisting of nickel and impurities resulting from the melting process.
Iron max. 1.5%
Manganese max. 0.5%
Silicon max. 0.10%
Cobalt max. 0.3%
Tungsten max. 0.3%
Copper max. 0.3%
Aluminum 0.1 to 0.3%
Magnesium 0.001 to 0.015 Calcium 0.001 to 0.015%
Carbon max. 0.01%
Nitrogen 0.08 to 0.12%
the rest consisting of nickel and impurities resulting from the melting process.
3. Nickel-chromium-molybdenum alloy as defined in Claim 1 or Claim 2, characterized by the following additives (% by mass):
Boron max. 0.0030%
Phosphorous max. 0.020%
Sulphur max. 0.010%
Niobium max. 0.20%
Titanium max. 0.02%
Boron max. 0.0030%
Phosphorous max. 0.020%
Sulphur max. 0.010%
Niobium max. 0.20%
Titanium max. 0.02%
4. Nickel alloy as defined in one of the Claims 1 to 3, with a chromium: molybdenum ration of 1.9 to 2.3, calculated on substance quantity content.
5. Use of a nickel alloy as defined in one of the Claim 1 to 4 for component parts of chemical plants.
6. Use of a nickel alloy as defined in one of the Claims 1 to 4 as welding filler for super-alloyed welding of highly-alloyed NiCrMo materials and as a welding filler of the same type, with little segregation, with itself.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19723491A DE19723491C1 (en) | 1997-06-05 | 1997-06-05 | Use of a nickel-chromium-molybdenum alloy |
| DE19723491.7 | 1997-06-05 | ||
| PCT/EP1998/003117 WO1998055661A1 (en) | 1997-06-05 | 1998-05-27 | Nickel-chromium-molybdenum alloy |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2291051A1 true CA2291051A1 (en) | 1998-12-10 |
Family
ID=7831419
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002291051A Abandoned CA2291051A1 (en) | 1997-06-05 | 1998-05-27 | Nickel-chromium-molybdenum alloy |
Country Status (14)
| Country | Link |
|---|---|
| EP (1) | EP0991788B1 (en) |
| JP (1) | JP2000512345A (en) |
| KR (1) | KR20010013420A (en) |
| CN (1) | CN1249010A (en) |
| AT (1) | ATE204922T1 (en) |
| AU (1) | AU7915998A (en) |
| BR (1) | BR9809950A (en) |
| CA (1) | CA2291051A1 (en) |
| DE (2) | DE19723491C1 (en) |
| IL (1) | IL131813A0 (en) |
| NO (1) | NO995960D0 (en) |
| PL (1) | PL337189A1 (en) |
| TR (1) | TR199902973T2 (en) |
| WO (1) | WO1998055661A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10988829B2 (en) | 2016-12-21 | 2021-04-27 | Vdm Metals International Gmbh | Method for producing nickel alloys with optimized strip weldability |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6579388B2 (en) | 2001-06-28 | 2003-06-17 | Haynes International, Inc. | Aging treatment for Ni-Cr-Mo alloys |
| KR20030003016A (en) * | 2001-06-28 | 2003-01-09 | 하이네스인터내셔널인코포레이티드 | AGING TREATMENT FOR Ni-Cr-Mo ALLOYS |
| JP4519520B2 (en) * | 2003-09-24 | 2010-08-04 | 新日鐵住金ステンレス株式会社 | High Ni-base alloy welding wire |
| CA2572157C (en) * | 2004-06-30 | 2015-02-10 | Sumitomo Metal Industries, Ltd. | Ni base alloy pipe stock and method for manufacturing the same |
| DE102008007605A1 (en) | 2008-02-04 | 2009-08-06 | Uhde Gmbh | Modified nickel |
| DE102013101631A1 (en) | 2012-03-06 | 2013-09-12 | Babcock Borsig Steinmüller Gmbh | Corrosion resistant heat exchanger |
| JP5725630B1 (en) * | 2014-02-26 | 2015-05-27 | 日立金属Ｍｍｃスーパーアロイ株式会社 | Ni-base alloy with excellent hot forgeability and corrosion resistance |
| US9970091B2 (en) * | 2015-07-08 | 2018-05-15 | Haynes International, Inc. | Method for producing two-phase Ni—Cr—Mo alloys |
| WO2018011467A1 (en) * | 2016-07-11 | 2018-01-18 | Outotec (Finland) Oy | Process for manufacturing ferrochromium alloy with desired content of manganese, nickel and molybdenum |
| CN106756245B (en) * | 2016-10-31 | 2018-08-28 | 重庆材料研究院有限公司 | A kind of alloy material and preparation method thereof for nuclear field liquid waste processing tankage |
| DE102016124588A1 (en) * | 2016-12-16 | 2018-06-21 | Vdm Metals International Gmbh | USE OF NICKEL CHROM MOLYBDENE ALLOY |
| RU2672647C1 (en) * | 2017-08-01 | 2018-11-16 | Акционерное общество "Чепецкий механический завод" | Corrosive-resistant alloy |
| EP4129533A4 (en) * | 2020-03-31 | 2024-02-21 | Proterial Ltd | Alloy, alloy powder, alloy member, and composite member |
| JP7089555B2 (en) * | 2020-07-03 | 2022-06-22 | 大同特殊鋼株式会社 | Manufacturing method of current detection resistor, circuit board and current detection resistor |
| CN114182121B (en) * | 2021-11-22 | 2023-07-04 | 山东瑞安泰医疗技术有限公司 | Preparation method of orthopedic fixing material of degradable metal molybdenum-base alloy |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB674723A (en) * | 1949-02-17 | 1952-07-02 | Rolls Royce | Improvements relating to processes of manufacturing engineering parts from heat resisting alloys |
| IT1216044B (en) * | 1988-03-10 | 1990-02-22 | Alfa Lancia Ind | REARVIEW MIRROR WITH ADJUSTABLE SUPPORT FOR VEHICLES. |
| US5019184A (en) * | 1989-04-14 | 1991-05-28 | Inco Alloys International, Inc. | Corrosion-resistant nickel-chromium-molybdenum alloys |
| DE4203328C1 (en) * | 1992-02-06 | 1993-01-07 | Krupp Vdm Gmbh, 5980 Werdohl, De | |
| US5441384A (en) * | 1993-10-15 | 1995-08-15 | Hydro West Group, Inc. | Hydraulic turbine and guide gate apparatus and runner apparatus therefor |
| JPH07316699A (en) * | 1994-05-18 | 1995-12-05 | Mitsubishi Materials Corp | Corrosion-resistant nitride-dispersed nickel base alloy having high hardness and strength |
| US6280540B1 (en) * | 1994-07-22 | 2001-08-28 | Haynes International, Inc. | Copper-containing Ni-Cr-Mo alloys |
| JP3485980B2 (en) * | 1994-10-03 | 2004-01-13 | Ｊｆｅスチール株式会社 | Method for producing welded clad steel pipe for boiler |
-
1997
- 1997-06-05 DE DE19723491A patent/DE19723491C1/en not_active Expired - Fee Related
-
1998
- 1998-05-27 BR BR9809950-7A patent/BR9809950A/en not_active Application Discontinuation
- 1998-05-27 AT AT98929384T patent/ATE204922T1/en not_active IP Right Cessation
- 1998-05-27 JP JP11501428A patent/JP2000512345A/en active Pending
- 1998-05-27 EP EP98929384A patent/EP0991788B1/en not_active Expired - Lifetime
- 1998-05-27 CA CA002291051A patent/CA2291051A1/en not_active Abandoned
- 1998-05-27 TR TR1999/02973T patent/TR199902973T2/en unknown
- 1998-05-27 KR KR19997011421A patent/KR20010013420A/en not_active Application Discontinuation
- 1998-05-27 WO PCT/EP1998/003117 patent/WO1998055661A1/en not_active Application Discontinuation
- 1998-05-27 DE DE59801333T patent/DE59801333D1/en not_active Expired - Lifetime
- 1998-05-27 CN CN98802882A patent/CN1249010A/en active Pending
- 1998-05-27 IL IL13181398A patent/IL131813A0/en unknown
- 1998-05-27 AU AU79159/98A patent/AU7915998A/en not_active Abandoned
- 1998-05-27 PL PL98337189A patent/PL337189A1/en unknown
-
1999
- 1999-12-03 NO NO995960A patent/NO995960D0/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10988829B2 (en) | 2016-12-21 | 2021-04-27 | Vdm Metals International Gmbh | Method for producing nickel alloys with optimized strip weldability |
Also Published As
| Publication number | Publication date |
|---|---|
| ATE204922T1 (en) | 2001-09-15 |
| EP0991788B1 (en) | 2001-08-29 |
| NO995960L (en) | 1999-12-03 |
| AU7915998A (en) | 1998-12-21 |
| DE59801333D1 (en) | 2001-10-04 |
| JP2000512345A (en) | 2000-09-19 |
| CN1249010A (en) | 2000-03-29 |
| PL337189A1 (en) | 2000-08-14 |
| BR9809950A (en) | 2000-08-01 |
| DE19723491C1 (en) | 1998-12-03 |
| IL131813A0 (en) | 2001-03-19 |
| TR199902973T2 (en) | 2000-02-21 |
| KR20010013420A (en) | 2001-02-26 |
| EP0991788A1 (en) | 2000-04-12 |
| WO1998055661A1 (en) | 1998-12-10 |
| NO995960D0 (en) | 1999-12-03 |
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