Use of nickel-iron-chromium alloys having good workability and strength together with high resistance in highly corrosive environments

Abstract

A powder of nickel-iron-chromium alloy having excellent high-temperature corrosion resistance, the powder being composed of spherical particles having a size of 5 to 250 μm, the alloy being composed of (by mass%): 35.0 to 38% nickel, 26.0 to 30.0% chromium, more than 0.7 to 1.50% silicon, 0.40 to 1.30% aluminum, 0.00 to 1.0% manganese, 0.0001 to 0.05% magnesium, 0.015-0.12% Ca, 0.001-0.150% Nitrogen, 0.001-0.030% Phosphorus, 0.0001-0.100% Oxygen, Max. 0.010% Sulfur, Less than 1.0% Molybdenum, Less than 1.0% Cobalt, Less than 0.5% Copper, Less than 1.0% Tungsten, Balance Iron, and Normal Process Impurities, with the following relationship: Fc=-1.2+0.29×Ni-4.6×Si-4.4×Al≦2.5 (1a) must be satisfied, where Ni, Si and Al are the concentrations in mass % of the corresponding elements.

Description

[Technical field]

[0001] The present invention relates to the use of nickel-iron-chromium alloys having good high temperature corrosion resistance in highly corrosive environments, as well as good workability and strength. [Background technology]

[0002] Austenitic nickel-iron-chromium alloys having various nickel, chromium and iron contents have long been used in furnace construction and in the chemical and petrochemical industries, where good high temperature corrosion resistance and good heat resistance are required in highly corrosive environments, such as carburizing, sulfiding and chlorinating environments.

[0003] It is noted that in general, the hot corrosion resistance of the alloys shown in Table 1 improves with increasing chromium content. All these alloys form a chromium oxide layer (Cr2O3) with a more or less closed silicon oxide layer underneath. Small additions of elements with high oxygen affinity, such as yttrium or cerium, improve the corrosion resistance. The chromium content builds up a protective layer and is slowly consumed in the course of use in the application area. A high chromium content therefore increases the life of the material, since a higher chromium content of the elements forming the protective layer postpones the point at which the chromium content falls below a critical value and oxides other than Cr2O3 (such as iron- and nickel-containing oxides) are formed. A further improvement in the hot corrosion resistance is achieved by the addition of silicon or aluminum. From a certain minimum content onwards, these elements form a closed layer underneath the chromium oxide layer, thus reducing the consumption of chromium.

[0004] In carburizing environments (CO, H2, CH4, CO2, H2O mixtures), carbon can penetrate into the material and lead to the formation of internal carbides. This causes a loss of notched impact strength. Chromium depletion of the matrix can also lead to transformation processes.

[0005] High resistance to carburization is achieved by materials with low solubility for carbon and low diffusion rate of carbon. Nickel alloys are therefore generally more resistant to carburization than iron-based alloys, since both carbon diffusion and carbon solubility are lower in nickel than in iron. An increase in chromium content results in higher resistance to carburization due to the formation of a protective chromium oxide layer, as long as the oxygen partial pressure in the gas is not insufficient for the formation of this layer. At very low oxygen partial pressures, materials can be used that form layers made of silicon oxide or the more stable aluminum oxide, both of which are able to form a protective oxide layer even at significantly lower oxygen contents.

[0006] In carburizing, sulfiding environments (CO, H2, H2O, CO2, H2S mixtures) with low oxygen partial pressure, sulfur can penetrate into the material, leading to the formation of sulfides. The melting point can also be reduced to very low values ​​(635 °C for Ni-Ni3S2 eutectic mixture, 988 °C for Fe-FeS eutectic mixture). In sulfiding environments, nickel-iron-chromium alloys with a high nickel content are often more sensitive than nickel-iron-chromium alloys with a high iron content. Here too, a further improvement in the high-temperature corrosion resistance can be achieved by the addition of silicon or aluminum.

[0007] In chlorinated environments with low oxygen partial pressure, volatile metal chlorides with high vapor pressures and / or low melting points can form, resulting in high corrosion rates. Higher chromium and / or nickel contents improve corrosion resistance.

[0008] German Patent Specification DE 41 30 139 C1 describes a heat-resistant, hot-formable austenitic nickel alloy which consists (in mass%) of 0.05-0.15% carbon, 2.5-3.0% silicon, 0.2-0.5% manganese, max. 0.015% phosphorus, max. 0.005% sulfur, 25-30% chromium, 20-27% iron, 0.05-0.15% aluminium, 0.001-0.005% calcium, 0.05-0.15% rare earths, 0.05-0.20% nitrogen, the balance being nickel and impurities resulting from normal melting.

[0009] The alloy described in German patent DE 4130139 is known under the names "NiCr28FeSiCe", Alloy 45™, Nicrofer 45™ or under the material number 2.4889 and will be referred to below as "45™".

[0010] Since alloy 45TM is highly resistant in carburizing and sulfidizing media, it is suitable for use in waste incineration plants or coal gasification plants. Figure 1 shows the metallographically determined corrosion attack depth for various alloys after 2100 hours of aging in H2S-containing gas at the PRENFLO coal gasification pilot plant in Fürstenhausen as a function of temperature for various alloys. Table 1 shows the composition of the investigated alloys according to the prior art. A high chromium content and a high silicon content significantly reduce the corrosion attack depth. A high silicon content of 2.5% or more allows the formation of a silicon oxide layer under the chromium oxide protective layer, which results in high corrosion resistance of the material. 45TM with 26-29% chromium and 2.5-3% silicon shows the lowest corrosion attack depth at all temperatures, followed by AC66 with 26-28% chromium and up to 0.3% silicon.

[0011] However, alloy 45TM is very difficult to process, as evidenced, for example, by the formation of cracks during hot forming. 45TM also has a tendency to form cracks during welding, which makes inherent welding (with filler metal within the composition range of the material to be welded), which is reasonable for corrosion protection reasons, impossible, and makes the practical use of the material difficult. The reasons for the enhanced formation of hot cracks for austenitic FeCrNi weld metals with primary austenite solidification include the formation of low melting phases due to silicon enrichment at the austenite grain boundaries (eutectic mixture Fe-Fe2Si: 1212°C, eutectic mixture NiSi-Ni3Si2: 964°C, and NiSi: 996°C), as well as the large freezing range.

[0012] In contrast, alloy AC66 (see Table 1 for composition) has sufficient weldability and fabricability, but is not very corrosion resistant in coal gasification equipment, as shown in FIG.

[0013] The material requirements are further increased when carburizing and sulfidizing conditions are combined with chlorine attack, as occurs in coal gasification and waste incineration plants.

[0014] For materials to be usable in carburizing, sulfiding and chlorinating environments, especially in atmospheres, compromises must be made in composition.

[0015] Heat resistance is improved especially by a high carbon content, but also by high contents of solution strengthening elements such as chromium, aluminum, silicon, molybdenum and tungsten.

[0016] US 6,623,869 B1 describes a metallic material containing, by weight, the following: 0.2% or less carbon, 0.01-4% silicon, 0.05-2% manganese, 0.04% or less phosphorus, 0.015% or less sulfur, 10-35% chromium, 30-78% nickel, 0.005% or more aluminum but less than 4.5%, 0.005-0.2% nitrogen, and 0.015-3% copper and / or 0.015-3% cobalt, the balance being essentially iron, where 40Si+Ni+5Al+40N+10(Cu+Co) is 50 or more, and the symbols of the elements in the formula represent the alloy content of each element. The metal material has excellent corrosion resistance in an environment where metal dusting may occur, so it can be used in furnace tubes, piping systems, heat exchanger tubes, etc. in oil refineries or petrochemical facilities, which can significantly improve the durability and safety of the facilities.

[0017] US 3,833,358 A describes a refractory iron-based alloy, which provides high resistance to creep, thermal shock, thermal fatigue and intergranular oxidation, as well as good weldability, and which contains essentially (by mass percentage) the following elements: C 0.05~0.20 Ni 30~40 Cr 20~30 Nb 0.2~2 N 0.04~0.2 Mn 0.6~2 Si 0.6~2 Ta 0~0.3 Ti 0~1 Mo 0~0.5 Al 0~0.05 Pb 0~0.01 Sn 0~0.01 Zinc 0~0.01 Cu 0~0.25 and the remainder essentially iron, wherein the mass proportions of the above elements satisfy the following formula: 30×C%+Ni%+0.5×Mn%+16×N%=Cr%+0.5×(Nb+1 / 2Ta)%+3.5×Ti%+1.5×Si%+Mo%+(11±2)% A=B±20% Here, A = 30 × C%, B = 2 × Ti% + 6 × (Nb + 1 / 2Ta)%.

[0018] US 3,865,581 A describes heat-resistant alloys having hot formability, mainly consisting of 0.01-0.5% C, 0.01-2.0% Si, 0.01-3.0% Mn, 22-80% Ni and 10-40% Cr, together with 0.0005-0.20% B and / or 0.001-6.0% Zr, and further with one or more of 0.001-0.5% Ce, 0.001-0.2% Mg and 0.001-1.0% Be, the balance being iron and unavoidable impurities. They are suitable for use in furnace structures (burner tips, protective housings, protective tubes for thermocouples, etc.).

[0019] DE 1024719 A describes the addition of cerium and / or lanthanum to a nickel-iron alloy, which is a hot-formable alloy characterized by the following composition: 0-0.5% carbon, 10-60% one or more of the elements chromium, molybdenum and tungsten (the amount of each of these elements not exceeding 30%), 0-73% iron, 0.02-1.10% cerium and / or lanthanum, the balance 4-70% nickel (including impurities), with the proviso that the content of the rare earth metals is combined with the nickel content as follows: % of Nickel % of Cerium and / or Lanthanum 4 Approx. 0.02~1.10 10 Approx. 0.02~1.05 20 Approximately 0.02~0.90 30 Approx. 0.02~0.75 40 Approx. 0.02~0.60 50 approx. 0.02~0.45 60 approx. 0.02~0.30 70 Approximately 0.02~0.15.

[0020] EP 0 812 926 A1 describes a nickel-base alloy that has 0.06-0.14% carbon, 35-46% nickel, 22.5-26.5% chromium, 0-1.5% manganese, 0.5-2% silicon, 0.1-1% titanium, 0.05-2% aluminum, 1-3% molybdenum, 0.2% niobium, 0.1-1% tantalum, 0-0.3% tungsten, 0-0.008% boron, 0-0.05% zirconium, and the balance iron and incidental impurities, and that has increased strength in use.

[0021] WO 2007 / 124996 A1 describes a reaction vessel for use in the production of hydrogen sulfide by reaction of sulfur with hydrogen, the reaction vessel and possibly the connecting lines, as well as the fittings and the measuring and control mechanisms, being made of an aluminum-containing material which is partially or completely resistant to the reaction mixture, in particular the material contains the following components: 0-0.3% C, 0-2.5% Si, 0-2.5% Mn, 0-0.1% P, 0-0.3% S, 15.0-28.0% Cr, 0-1.0% Cu, 0-balance % Fe, 1.0-5.0% Al, 0-2.5% Co, 0-1.5% Ti, 0-0.4% Y and up to 70% Ni (% by weight).

[0022] DE 10 2007 005 605 A1 describes an iron-nickel-chromium-silicon alloy having (in mass%) 34-42% nickel, 18-26% chromium, 1.0-2.5% silicon and the additives 0.05-1% Al, 0.01-1% Mn, 0.01-0.26% lanthanum, 0.0005-0.05% magnesium, 0.01-0.14% carbon, 0.01-0.14% nitrogen, max. 0.01% sulfur, max. 0.005% boron, the balance being iron and normal process-induced impurities. This alloy is used in heating elements.

[0023] US 5,021,215 A discloses a high strength heat resistant steel with improved formability, which essentially (in mass %) comprises C: 0.05~0.30%, Si: 3.0% or less, Mn: 10% or less, Cr: 15~35%, Ni: 15~50%, Mg: 0.001~0.02%, B: 0.001~0.01%, Zr: 0.001~0.10%, At least one of the following elements: Ti: 0.05-1.0%, Nb: 0.1-2.0%, and Al: 0.05-1.0%, Mo: 0-3.0%, W: 0-6.0%, (Mo+1 / 2W=3.0% or less) The balance is Fe and incidental impurities, the impurities oxygen and nitrogen are limited to 50 ppm or less or 200 ppm or less, and the austenite grain size number is limited to No. 4 or greater.

[0024] JP 56163244 A describes the improvement of hot workability and oxidation resistance of austenitic steels by adding specific amounts of C, Si, Mn, Ni, Cr, Al, B, rare earth elements, and Ca to the steels. This is achieved by an austenitic steel having the following composition in mass percent: <0.2% C, 1.5-3.5% Si, <2% Mn, 8-35% Ni, 15-30% Cr, <2% Al, 0.0005-0.005% B, 0.005-0.1% rare earth elements, and 0.0005-0.02% Ca, or with an additional addition of 0.0005-0.03% Mg if necessary. The resulting austenitic steel is smelted in a conventional steelmaking furnace and the molten steel is formed into billets which are then hot rolled.

[0025] US 7,118,636 B2 describes a nickel-iron-chromium alloy containing solidification phases that allow the alloy to retain its microstructure at high temperatures during forging and processing. The alloy contains sufficient amounts of titanium, zirconium, carbon and nitrogen to form fine titanium and zirconium nitrides, even though they are near their solubility limits in the molten state of the alloy. When such an alloy is used to produce articles through thermomechanical processing, a dispersion of fine titanium and zirconium carbonitride precipitates occurs during solidification of the melt and remains in the alloy during subsequent processing steps (at high temperatures) to inhibit austenite grain growth. The nickel-iron-chromium alloy contains less than 0.05 mass % niobium, at least 0.05% zirconium, at least 0.05% carbon, at least 0.05% nitrogen (the mass ratio of carbon to nitrogen is at least 1:2 to less than 1:1), sufficient titanium, zirconium and / or aluminum to be free of chromium carbides, and sufficient titanium, zirconium, carbon and nitrogen to form a uniform dispersion of fine titanium carbonitride and zirconium carbonitride, and a sufficient amount of [(Ti x Zr 1-x )(C y N 1-y The nickel-iron-chromium alloy further comprises, by weight, about 32% to about 38% iron, about 22% to about 28% chromium, about 0.10% to about 0.60% titanium, about 0.05% to about 0.30% zirconium, about 0.05% to about 0.30% carbon, about 0.05% to about 0.30% nitrogen, about 0.05% to about 0.5% aluminum, up to 0.99% molybdenum, up to about 0.01% boron, up to about 1% silicon, up to about 1% manganese, the balance being nickel, and incidental impurities.

[0026] Japanese Patent Publication No. 57-134544 (JPS 57134544 A) describes the improvement of the resistance to stress corrosion cracking of oil country tubular goods by adding certain amounts of Mo, W, etc. to a high Cr-Ni steel as the material for the tube. For this purpose, a steel having a composition of <0.10% C, <1.0% Si, <2.0% Mn, <0.030% P, <0.005% S, <0.5% Al, 22.5-30% Cr, 25-60% Ni and Mo and / or W, and having the formula Cr(%)+10×Mo(%)+5×W(%)≧70% 4%≦Mo(%)+1 / 2W(%)<8% The alloy steels satisfying the above conditions are used. The steels are used for OCTGs used in highly corrosive and harsh environments such as oil wells and natural gas wells. The alloys may contain <1% Cu and / or <2% Co and / or <0.10% of one or more rare earth elements, <0.20% Y, <0.10% Mg, <0.10% Ca and <0.5% Ti. OCTGs with excellent stress corrosion cracking resistance in the highly corrosive environments of oil wells containing H2S, CO2 and Cl can be produced. [Prior art documents] [Patent documents]

[0027] [Patent Document 1] German Patent No. DE4130139 [Patent Document 2] U.S. Patent No. 6,623,869 [Patent Document 3] U.S. Pat. No. 3,833,358 [Patent Document 4] German Patent No. 1024719 [Patent Document 5] European Patent Application Publication No. 0812926 [Patent Document 6] International Publication No. 2007 / 124996 [Patent Document 7] DE 102007005605 A1 [Patent Document 8] U.S. Patent No. 5,021,215 [Patent Document 9] Japanese Patent Application Publication No. 56-163244 [Patent Document 10] U.S. Patent No. 7,118,636 [Patent Document 11] Japanese Patent Publication No. 57-134544 Summary of the Invention [Problem to be solved by the invention]

[0028] The problem underlying the present invention is therefore: a) Good high-temperature corrosion resistance in highly corrosive environments, such as carburizing, sulfiding and chlorinating environments, comparable to that of Alloy 45TM; b) have sufficient workability, in particular weldability, as far as possible similar to alloy AC66, and c) has sufficient heat resistance at 500°C, similar to alloy AC66; The use of a nickel-iron-chromium alloy is envisaged. [Means for solving the problem]

[0029] The problem underlying the present invention is the use of a nickel-iron-chromium alloy having excellent high-temperature corrosion resistance as a powder, said powder consisting of spherical particles having a size of 5 to 250 μm, said alloy comprising (in mass %): 35.0-38% nickel, 26.0-30.0% chromium, >0.7-1.50% silicon; 0.40-1.30% aluminum, 0.00-1.0% manganese, 0.0001-0.05% each of magnesium and / or calcium, 0.015-0.12% carbon, 0.001-0.150% nitrogen, 0.001-0.030% phosphorus, 0.0001 to 0.100% oxygen, Maximum 0.010% sulfur, Less than 1.0% molybdenum, Cobalt less than 1.0% less than 0.5% copper, Less than 1.0% tungsten, The balance is iron and normal process impurities. Contains the following relations: Fc=-1.2+0.29×Ni-4.6×Si-4.4×Al≦2.5 (1a) must be satisfied, where Ni, Si and Al are the concentrations in mass % of the corresponding elements. The problem is solved by the above-mentioned use.

[0030] Further advantageous aspects of the subject matter of the invention emerge from the associated dependent claims.

[0031] The nickel content is 35.0-38.0%, and the preferred content can be adjusted within the following range: 35 or >35.0~<38.0% 35 or >35.0–37 or <37.0%.

[0032] The range of chromium element is 26.0-30.0%, and the preferred range can be adjusted as follows: >26.0~<30.0% 27.0 or >27.0-30.0 or <30.0% 28.0 or >28.0-30.0 or <30.0%.

[0033] The silicon content is >0.70-1.50%. Preferably, silicon can be controlled in the alloy within the following ranges: >0.70~<1.50% 0.80 or >0.80~1.50 or <1.50% 0.90 or >0.90~1.50 or <1.50% 0.80 or >0.80~1.50 or <1.50% 0.80 or >0.80-1.45 or <1.45%.

[0034] The aluminum content is between 0.40 and 1.30%, where again preferably the aluminum content can be adjusted as shown below: >0.40~<1.30% 0.50 or >0.50~1.30 or <1.30% 0.50 or >0.50~1.20 or <1.20% 0.50 or >0.50~1.10 or <1.10% 0.60 or >0.60-1.10 or <1.10%.

[0035] The same applies to the element manganese, which may be present in the alloy at 0.0-1.0%. Alternatively, the following ranges are also possible: >0.0~<1.00% >0.0~0.50 or <0.50% >0.0~0.05 or <0.05% 0.005 or >0.005~0.20 or <0.20% 0.005 or >0.005-0.10 or <0.10%.

[0036] Magnesium and / or calcium are also present with a content of 0.0001-0.05%. Preferably, these elements may be adjusted in the alloy as follows: 0.0001~0.030% 0.0001~0.020% 0.0002~0.015% 0.0010~0.010%.

[0037] The alloy contains 0.015-0.12% carbon. This can be preferably adjusted in the alloy within the following ranges: >0.015~<0.12% 0.03 or >0.03~0.10 or <0.10% 0.04 or >0.04~0.10 or <0.10% 0.05 or >0.05~0.10 or <0.10% 0.05 or >0.05-0.09 or <0.09%.

[0038] This also applies to the nitrogen element, which is contained in a content of 0.001 to 0.150%. The preferred content can be shown as follows: >0.001~<0.150% 0.010 or >0.010~0.140 or <0.140% 0.020 or >0.020~0.140 or <0.140% 0.050 or >0.050~0.140 or <0.140%.

[0039] The alloy further contains phosphorus in a content of 0.001 to 0.030%. The preferred contents can be indicated as follows: 0.001~0.015%.

[0040] The alloy further contains oxygen in a content of 0.0001 to 0.100%.

[0041] The element sulfur is expressed in the alloy at 0.010% maximum. The preferred contents may be expressed as follows: Sulphur max 0.008%.

[0042] Molybdenum is present in the alloy in an amount less than 1.0%. The molybdenum content may be further limited as follows: Mo max 0.50 or <0.50% Mo max 0.20 or <0.20% Mo max 0.10 or <0.10% Mo max 0.05 or <0.05% Mo max 0.02 or <0.02%.

[0043] Additionally, the alloy contains less than 1.0% cobalt. The cobalt content may be further limited as follows: Co max 0.50 or <0.50% Co max 0.20 or <0.20% Co max 0.10 or <0.10% Co max 0.05 or <0.05% Co max 0.015 or <0.015%.

[0044] Additionally, the alloy may contain less than 0.5% copper. The copper content may be further limited as follows: Cu max 0.30 or <0.30% Cu max 0.10 or <0.10% Cu max 0.05 or <0.05% Cu max 0.015 or <0.015%.

[0045] Tungsten is present in the alloy at a maximum content of 1.0%. The tungsten content may be further limited as follows: W <1.0% W max 0.50 or <0.50% W max 0.20 or <0.20% W max 0.10 or <0.10% W max 0.05 or <0.05% W max 0.02 or <0.02%.

[0046] The balance of the alloy consists of iron and normal process impurities. The iron content may be further limited as follows: 28.0 or >28.0–38.0% 29.0 or >29.0–38.0% 30.0 or >30.0–38.0 or <38.0%.

[0047] To provide sufficient resistance to carburizing, sulfidizing and chlorinating environments, the following relationship must be observed between nickel, silicon and aluminum: Fc=-1.2+0.29×Ni-4.6×Si-4.4×Al≦2.5 (1a) must be satisfied, where Ni, Si and Al are the concentrations in mass % of the corresponding elements.

[0048] The preferred range is: Fc=-1.2+0.29×Ni-4.6×Si-4.4×Al≦1.5 (1b) Fc=-1.2+0.29×Ni-4.6×Si-4.4×Al≦1.0 (1c) can be adjusted.

[0049] The addition of oxygen-affinity elements, such as cerium, lanthanum, yttrium and hafnium, improves corrosion resistance by being incorporated into the oxide layer where they block the diffusion paths of oxygen on grain boundaries.

[0050] Optionally, the alloy may contain 0.001-0.20% each of one or more of the elements cerium, lanthanum, yttrium, zirconium, and hafnium, where the elements have the following formula: FRE=0.714×Ce+0.720×La+1.124×Y+1.096×Zr+0.560×Hf≦0.10 (2a) must be satisfied, where Ce, La, Y, Zr and Hf are the concentrations in mass % of the corresponding elements.

[0051] Preferably, when at least one element of cerium, lanthanum, yttrium, zirconium and hafnium is present, the FRE may be adjusted as follows: FRE=0.714×Ce+0.720×La+1.124×Y+1.096×Zr+0.560×Hf≦0.075 (2b) FRE=0.714×Ce+0.720×La+1.124×Y+1.096×Zr+0.560×Hf≦0.065 (2c).

[0052] Alternatively, when cerium and lanthanum are present simultaneously, cerium mischmetal (abbreviated as CeMM) can also be used in a content of 0.001-0.20%, where FRE is: FRE=0.716×CeMM+1.124×Y+1.096×Zr+0.560×Hf≦0.10 (3a) where CeMM, Y, Zr and Hf are the concentrations in weight percent of the corresponding elements.

[0053] Preferably, when adding cerium mischmetal, the FRE can be adjusted as follows: FRE=0.716×CeMM+1.124×Y+1.096×Zr+0.560×Hf≦0.075 (3b) FRE=0.716×CeMM+1.124×Y+1.096×Zr+0.560×Hf≦0.065 (3c).

[0054] Preferably, cerium, lanthanum, cerium mischmetal, zirconium and hafnium may be contained in the alloy within ranges as follows: >0.001~<0.20% 0.001 or >0.001 to 0.15 or <0.15% 0.001 or >0.001~0.10 or <0.10% 0.001 or >0.001 to 0.08 or <0.08% 0.001 or >0.001~0.05 or <0.05% 0.001 or >0.001~0.04 or <0.04% 0.01 or >0.01-0.04 or <0.04%.

[0055] Preferably, yttrium may be included in the alloy within the following ranges: >0.001~<0.20% 0.001 or >0.001 to 0.15 or <0.15% 0.001 or >0.001~0.10 or <0.10% 0.001 or >0.001 to 0.08 or <0.08% 0.01 or >0.01~0.08 or <0.08% 0.01 or >0.01~<0.045%.

[0056] Optionally, the element titanium may be present in the alloy in a content of 0.0-0.50%. Preferably, titanium may be present in the alloy within the following ranges: >0.0~<0.50% >0.0~0.50 or <0.50% 0.001 or >0.001 to 0.20 or <0.20% 0.001 or >0.001 to 0.15 or <0.15% 0.001 or >0.001~0.10 or <0.10% 0.001 or >0.001~0.05 or <0.05% 0.001 or >0.001~0.04 or <0.04% 0.005 or >0.005~0.20 or <0.20% 0.010 or >0.010-0.20 or <0.20%.

[0057] Optionally, the niobium element may be adjusted in the alloy at a content of 0.0-0.2%. Preferably, niobium may be contained in the alloy within the following ranges: >0.0~<0.20% >0.0~0.15 or <0.15% >0.0~0.10 or <0.10% >0.0~0.05 or <0.05% >0.0~0.02 or <0.02% 0.001 or >0.001 to 0.20 or <0.20% 0.010 or >0.010-0.20 or <0.20%.

[0058] Optionally, 0.0 to 0.20% tantalum may also be included in the alloy. The preferred contents may be shown as follows: >0.0~<0.20% >0.0~0.10 or <0.10% >0.0~0.05 or <0.05%.

[0059] Optionally, the element boron may be contained in the alloy in a content of 0.0001 to 0.008%. The preferred contents may be shown as follows: Boron 0.0005~0.008% Boron 0.0005~0.005% Boron 0.0005-0.004%.

[0060] Additionally, the alloy may contain up to 0.50% vanadium.

[0061] V <0.50% V max 0.40 or <0.50% V max 0.20 or <0.20% V max 0.08 or <0.10% V max 0.05 or <0.05%.

[0062] Finally, for impurities, the elements lead, zinc and tin may also be indicated in percentages as follows: Pb max. 0.002%, Zn max. 0.002%, Sn max. 0.002%.

[0063] Additionally, the element beryllium may be represented as follows: Be less than 0.001%.

[0064] The powder according to the invention is preferably produced in a vacuum inert gas atomization apparatus (VIGA). For this, the alloy is first melted, optionally in open or vacuum, optionally followed by ESU and / or VAR remelting. The powder is then produced by atomizing the molten alloy in a vacuum inert gas atomization apparatus (VIGA). In this apparatus, the alloy is melted in a vacuum induction melting (VIM) and directed into an injection funnel, which is connected to a gas nozzle, where the molten metal is atomized into metal particles with the aid of an inert gas under high pressure of 5-100 bar. The molten metal is heated in a melting crucible at 5-400°C above the melting point. The metal flow rate during atomization is 0.5-80 kg / min and the gas flow rate is 2-150 m 3 / min. By rapid cooling, the metal particles solidify into spheres (spherical grains). The inert gas used during spraying may contain 0.01-100% nitrogen, if necessary. The gas phase is then separated from the powder in a cyclone, and the powder is subsequently packaged.

[0065] In this case, the particles have a particle size of 5 to 250 μm, a pore area (pores > 1 μm) of 0.0 to 4% of the total area of ​​the evaluated object, and a gas inclusion density of 2 to about 8.5 g / cm 3 The alloy has a bulk density of up to the alloy density of 1000 g / mol / g and is hermetically packed under a protective gas atmosphere with argon.

[0066] The particle size range of the powder is 5-250 μm, with preferred ranges being 5-150 μm or 10-150 μm. Said preferred ranges can be achieved by separating out too fine and too large particles by sieving or screening steps. These steps are carried out under protective gas and can be carried out one or more times.

[0067] The powder has a pore area (pores > 1 μm) of gas inclusions of 0.0-4% of the total area of ​​the object being evaluated, with the preferred range being 0.0~2% 0.0~0.5% 0.0~0.2% 0.0~0.1% 0.0~0.05% It is.

[0068] The powder has a mass of 2 g / cm 3 ~The density of the alloy is about 8.5g / cm 3 wherein preferred ranges may be the following values: 4~5g / cm 3 2~8g / cm 3 2~7g / cm 3 3~6g / cm 3 .

[0069] The amount of gas inclusions in the powder can reduce the porosity remaining in the produced part.

[0070] The inert gas during powder production may alternatively be argon or a mixture of argon with 0.01 to less than 100% nitrogen. The nitrogen content may be subject to the following limitations: 0.01~80% 0.01~50% 0.01~30% 0.01~20% 0.01~10% 0.01~10% 0.1-5% 0.5~10% 1-5% 2~3%.

[0071] Alternatively, the inert gas may optionally be helium.

[0072] The inert gas should preferably have a purity of at least 99.996% by volume, in particular a nitrogen content of 0.0-10 ppmvm, an oxygen content of 0.0-4 ppmv, and an H2O content ≦ 5 ppmv.

[0073] In particular, the inert gas may preferably have a purity of at least 99.999% by volume. In particular, it should have a nitrogen content of 0.0-5 ppmv, an oxygen content of 0.0-2 ppmv, and an H2O content of ≦3 ppmv.

[0074] The dew point in the apparatus is in the range of -10 to -120°C. It is preferably in the range of -30 to -100°C.

[0075] The pressure during spraying of the powder may preferably be 10 to 80 bar.

[0076] Powders so produced from the alloys can be used for any manufacturing method that uses powder to produce a component or a layer on a component.

[0077] The powders so produced can in particular be used for the additive production of components or layers on components.

[0078] Additive manufacturing is also understood as the concept of generative manufacturing, rapid technology, rapid tooling, rapid prototyping or the like.

[0079] In general, a distinction is made here between: 3D printing with powder, Selective laser sintering, and Selective laser melting, Electron Beam Melting Binder Jetting Laser cladding welding High speed laser cladding Ultra-high speed laser cladding welding selective electron beam melting, etc.

[0080] Components or layers on components manufactured using additive manufacturing are built up from layer thicknesses of 5-600 μm and immediately after manufacture have an organized structure with grains extending in the direction of the structure and having an average grain size of 2 μm to 1000 μm, the preferred range being 5-600 μm.

[0081] The powder produced from the alloy can be used for binder jetting, where the component is built up in layers. In contrast to laser melting, however, an organic binder is applied locally, which ensures the connection of the powder particles. After hardening of the binder, the so-called green part is cleaned of the unbound powder and subsequently debound and sintered.

[0082] For powders produced from the alloy, methods and additional devices for pre-heating and post-heating can be advantageous. As an example, the EBM method - electron beam melting can be considered. A powder bed is selectively melted layer by layer by an electron beam. This process is carried out under high vacuum. Therefore, this process is particularly suitable for hard substances with low ductility and / or for reactive materials. Pre-heating and post-heating devices can also be integrated into the laser-based method.

[0083] Furthermore, the powders produced from the alloys can be used for the production of components, if necessary by HIP (hot isostatic pressing) or conventional sintering and extrusion methods. Furthermore, a combination of the methods of additive manufacturing and subsequent HIP treatment is possible. If necessary, it is also possible to carry out subsequent hot forming and / or cold forming, if necessary, or alternating hot and cold forming. For hot forming, the components can optionally be annealed at temperatures between 800 and 1290 ° C for 0.1 to 70 hours, then hot formed and optionally intermediate annealed at 800 to 1290 ° C for 0.05 to 70 hours. During and / or at the end of the hot forming, the surface of the material can optionally be (possibly several times) chemically and / or mechanically removed and cleaned. For cold forming, cold forming can be carried out to a degree of deformation of up to 98%, optionally with intermediate annealing at 800-1250°C for 0.05 min to 70 h, optionally under a protective gas, such as argon or hydrogen, followed by cooling in air, in a moving annealing atmosphere or in a water bath.

[0084] Components or layers on components produced from powders by various methods can optionally be subjected to a solution heat treatment at temperatures in the range of 700-1250° C. for 0.1 min to 70 h, optionally under protective gas, such as argon or hydrogen, followed by cooling in air, in a moving annealing atmosphere or in a water bath. Optionally, the surface can then be cleaned or processed by pickling, blasting, grinding, turning, peeling, milling. Such processing can optionally be carried out partially or entirely even before annealing.

[0085] A component, or layer on a component, made from said powder has an average grain size after annealing of 2 μm to 2000 μm, with a preferred range being 20 to 600 μm.

[0086] Components or layers on components manufactured from the powder according to the invention should preferably be used in areas where highly corrosive conditions prevail, such as carburizing or sulfurizing or chlorinating environments, or carburizing and chlorinating environments, or carburizing and sulfurizing and chlorinating environments, especially in areas where atmospheres prevail, as occurs, for example, in waste incineration plants, in pyrolysis plants, in refinery furnaces, in the chemical industry, in coal gasification plants and in industrial furnace structures, in activated carbon filters, components for the pyrolysis of waste and in precious metal recovery. [Brief description of the drawings]

[0087] [Figure 1] FIG. 1 shows the corrosion attack depth for various alloys after 2100 hours aging in the Prenflo pilot facility in H2S containing gas as a function of temperature. EXAMPLES

[0088] Tests performed The evaluation of high temperature corrosion resistance under highly corrosive conditions is carried out (at Dechema) via the resistance of materials in flowing synthetic gas atmospheres possessing this property at elevated temperatures, in the example of carburizing and sulfidizing and chlorinating environments.

[0089] For this purpose, dimensions 20 x 8 x 4 mm 3 Samples were cut from the respective alloy blanks, then a hole with a diameter of 3 mm was drilled and subsequently wet polished with SiC paper up to 1200 grit (grain size about 15 μm). The samples were degreased and cleaned with isopropanol in an ultrasonic bath. Each sample was suspended in a reaction vessel over a ceramic crucible using this hole to receive the corrosion products that may spall off, and the mass of the spalls could be determined by weighing the crucible containing the corrosion products. The sum of the mass of the spalls and the mass change of the sample is the total mass change of the sample. The specific mass change is the mass change with respect to the surface of the sample. These are referred to below as m for the specific net mass change and m for the specific net mass change. Netto , and m for the specific total mass change Brutto , and the specific mass change of the exfoliated oxide is m spall It is called.

[0090] Through the reaction vessel space flowed a gas mixture of 60% CO, 30% H2, 4% CO2, 1% H2S, 0.05% HCl and 3.95% H2O. This mixture has carburizing (60% CO), sulfidizing (1% H2S) and chlorinating (0.05% HCl) effects. The tests were carried out at 500°C. The test duration was 1056 hours each, divided into 11 cycles of 96 hours each. In each test there were two samples per alloy. The values ​​shown are the average values ​​of these two samples.

[0091] In the following investigation, after 1056 hours Total mass increase ≦2.0mg / cm 2 (4) are considered to be resistant in carburizing, sulfidizing and chlorinating environments.

[0092] This is because the relationship between nickel, silicon and aluminum is as follows: Fc=-1.2+0.29×Ni-4.6×Si-4.4×Al≦2.5 (1a) where Ni, Si and Al are the concentrations in mass % of the respective elements.

[0093] The weldability is assessed via the magnitude of hot crack formation during welding: the greater the risk of hot crack formation, the worse the weldability of the material.

[0094] In order to quantify the susceptibility to hot cracking, various alloys were tested at BAM (Federal Institute for Materials Testing and Testing) by means of the MVT (Modified Varestraint-TransVarestraint) test. For this, specimens with dimensions 100 mm x 40 mm x 10 mm are prepared from the alloys. For the MVT test, a TIG seam (TIG: tungsten inert gas) is placed lengthwise on the upper side of this specimen, fully machined, at a constant feed rate. When an arc passes through the middle of the specimen, a defined bending strain is applied on the specimen, which is then bent along the welding direction (Varestraint method). During this stage of bending, hot cracks are formed in a locally limited test area on the MVT specimen.

[0095] The tests were carried out at a bending strain of 4%, a drop (Gesenk) speed of 2 mm / s, and an energy per unit length of 7.5 kJ / cm, each under pure argon at 4.8.

[0096] For evaluation, the lengths of all solidification and reheat cracks visible on the specimen in an optical microscope at 25x magnification are identified and summed. Using these results, materials can be classified into categories of "hot cracking resistance" (area 1), "increased hot cracking tendency" (area 2), and "hot cracking hazard" (area 3) as shown in Table 2.

[0097] In the following investigation, alloys in region 1 "hot cracking resistance" and region 2 "increased hot cracking tendency" during MVT testing are considered to be well weldable because the prior art weldable alloy AC66 is in region 2. Alloys in danger of hot cracking (region 3) are usually difficult to weld, especially when welding with a specific filler metal (of similar composition to the material to be welded).

[0098] The heat resistance was evaluated through a hot tensile test, which was determined at the desired temperature in a tensile test according to DIN EN ISO 6892-2. p0.2 , tensile strength R m , and the elongation at break A were determined. The tests were carried out on round specimens with a diameter of 6 mm and an initial measurement length L030 mm in the measurement area. The yield strength R at 500 °C p0.2 Or tensile strength R m should reach at least the minimum value for alloy AC66 according to the prior art: 500℃: R p0.2 ≧95MPa or R m ≧115MPa (5a, 5b).

[0099] It is desirable that they be better than the prior art Alloy 45™ minimums.

[0100] 500℃: R p0.2 ≧150MPa or R m ≥ 500MPa (6a, 6b).

[0101] The particle size is examined using an intercept method.

[0102] manufacturing To verify the properties of components manufactured from powders, alloys melted in a vacuum furnace on a laboratory scale are used.

[0103] Tables 3a and 3b show the analysis of batches melted on a laboratory scale together with some melted batches according to the prior art AC66 (1.4877) and 45TM (2.4889) melted on an industrial scale cited for comparison. Batches according to the prior art are marked with T and those according to the invention with E. Batches melted on a laboratory scale are marked with L and batches melted on an industrial scale with G.

[0104] Blocks of laboratory scale vacuum melted alloys in Tables 3a and 3b were annealed at 900-1270°C for 8 hours and hot rolled to a final thickness of 13 or 6 mm using hot rolling and a further intermediate anneal at 900-1270°C for 0.1-1 hour. The sheets so produced were solution heat treated at 800-1250°C for 1 hour. From these sheets the specimens required for the measurements were produced.

[0105] For alloys melted on an industrial scale, samples were taken from an industrial scale production of factory-made sheets of appropriate thickness from which the specimens required for the measurements were produced.

[0106] All alloy variations typically had grain sizes between 50 and 190 μm.

[0107] For the example batches in Tables 3a and b, the following properties are compared: High corrosion resistance in highly corrosive environments, for example carburizing and high temperature corrosion resistance in sulfidizing and chlorinating environments - Weldability by MVT test Creep resistance by hot tensile test.

[0108] A summary of the results is shown in Table 4.

[0109] Table 4 shows the results of corrosion tests in the form of total mass change and spalling after 1056 hours at 500 °C in an atmosphere of 60% CO, 30% H2, 4% CO2, 1% H2S, 0.05% HCl and 3.95% H2O. All alloys tested have a chromium content of approximately 27-28%. The prior art alloy AC66, with only 0.2% silicon, is a notable difference at 10.92 mg / cm3. 2 The prior art Alloy 45™ with 2.6% silicon and all tested laboratory melted batches with silicon contents above 1.0% show a maximum total mass change of 2.0 mg / cm 2 The following total mass changes are shown (2209, 250098, 250101, 250105, 250102 and 250107). Furthermore, when the aluminum content is greater than 0.40%, the batches with a silicon content of 1.0% or less are also 2.0 mg / cm3 if the formula (1a) Fc≦2.5 is satisfied at the same time. 2 The following total mass changes can be had for batches 250084 (Si=0.59% and Al=0.95%), 250085 (Si=0.90% and Al=0.98%), 250106 (Si=0.98% and Al=0.80%), and 250108 (Si=0.70% and Al=0.86%).

[0110] Batches 250084, 250106, 250105, 250108 and 250107 are according to the invention, whereas batch 2209, having a silicon content above 1.50%, and batch 250098, having a nickel content of 44.0%, are not.

[0111] Batch 250098 (Si=1.20% and Al=0.85%) shows a similar or higher total mass gain despite a significantly increased silicon content of 1.2% compared to batches 250106 (Si=0.98% and Al=0.80%) and 250101 (Si=1.01% and Al=0.75%). Batch 250098 (Ni=44.0%) has a significantly increased nickel content compared to batches 250106 (Ni=35.6%) and 250101 (Ni=38.2%). This indicates that corrosion worsens with higher nickel content. Therefore, an upper limit for nickel is set at a maximum of 40%.

[0112] 2.0mg / cm 2 The total mass increase (3.43 mg / cm 2 In the case of batch 250100 not according to the invention (Ni=38.2%, Si=0.99% and Al=0.43%), the aluminum content is somewhat too low, in contrast to batch 250101 (Ni=38.2%, Si=1.01% and Al=0.75%), so that equation (1a) is not fulfilled. 2 The total mass increase (8.01 mg / cm 2 or 5.35 mg / cm 2 For batches 250103 (Ni=38.2, Si=0.36% and Al=0.82%) and 250099 (Ni=38.4%, Si=1.00% and Al=0.20%) not according to the invention, the silicon and aluminum contents are outside the claimed limits and furthermore formula (1a) is not satisfied.

[0113] The alloys 250084 and 250106 according to the invention still show spallation. Moreover, when the formula (1c) Fc≦1.0 is fulfilled, this alloy no longer shows spallation (250107) and, surprisingly, even in the case of a medium silicon content, a spallation of the order of 1.0 mg / cm 3 of 45TM with 2.6% silicon and 0.16% aluminum is observed. 2 The total mass change is significantly lower than that of the control.

[0114] Table 4 shows the weldability ratings of the alloys from the MTV test. Prior art weldable alloy AC66 is in Zone 2. Alloy 45TM is classified as Zone 3 (hot cracking hazard) and therefore has a high tendency to form cracks which make it difficult to weld and makes welding difficult or impossible with the proper filler metal.

[0115] All non-inventive batches with a silicon content of 1.50% or more (45TM, batches 2091, 2099, 2100, 2200, 2203, 2207, 2208, 2209) are in region 3. Of the batches with a silicon content of about 1.4%, those with an aluminum content of less than 0.1% are in region 2 (batches 2093, 2101), while those with a higher aluminum content are already in region 3 (batches 2103, 2096, 2097, 2098). All batches with a silicon content of less than 1.3% are in region 1 or 2 (AC66, batches 2095, 2102, 250084 to 250108). All laboratory batches according to the invention are in Zone 1 (batches 250084, 250106, 250105, 250108 and 250107) or Zone 2 (batch 250102).

[0116] The results of the hot tensile tests at 500°C in the table show that all alloys according to the invention melted on a laboratory scale had a yield strength R p0.2 are greater than 153 MPa, thus significantly exceeding the minimum value of 95 MPa for AC66. Although not significantly, they still exceed the minimum value of 150 MPa for 45TM (see Equations 5a and 6a). Also, the tensile strengths R m is greater than 192 MPa, and thus also significantly above the minimum of 115 MPa for AC66 (see Equation 5b). All hot tensile tests at 500°C had elongations greater than 35%.

[0117] Thus, the claimed limitations of alloy "E" according to the present invention as a powder can be illustrated as follows: A relatively low nickel content (with a simultaneous high iron content (balance)) promotes low corrosion in highly corrosive environments, such as carburizing and sulfiding and chlorinating atmospheres. A content of 40% is therefore the upper nickel limit. A too low nickel content (with a simultaneous high iron content (balance)) promotes the formation of sigma phases, especially at high chromium and silicon contents. A nickel content of 35% is therefore the lower limit.

[0118] Chromium improves the corrosion resistance in highly corrosive environments, such as carburizing and sulfiding and chlorinating atmospheres. A too low chromium content means that when the alloy is used in highly corrosive environments, the chromium concentration falls below the permissible limit very quickly and a closed chromium oxide layer can no longer be formed. Therefore, the lower limit for chromium is 26% chromium when used in highly corrosive environments, such as carburizing and sulfiding and chlorinating atmospheres. A too high chromium content, especially at high chromium contents, promotes the formation of sigma phase in the alloy. Therefore, an upper limit of 30% chromium is considered.

[0119] Silicon improves corrosion resistance in highly corrosive environments, such as carburizing and sulfiding and chlorinating atmospheres. Therefore, a minimum content of 0.40% is necessary. On the other hand, too high a content impairs weldability and promotes the formation of sigma phases, especially in the case of high chromium contents. Therefore, the silicon content is limited to 1.50%.

[0120] A certain aluminum content improves corrosion resistance in highly corrosive environments, such as carburizing and sulfiding and chlorinating atmospheres. Therefore, a minimum content of 0.40% is necessary. On the other hand, too high a content impairs weldability, especially in the case of high chromium and silicon contents. Therefore, the aluminum content is limited to 1.30%.

[0121] Manganese is useful for improving workability. Manganese is limited to 1.0% because this element reduces high-temperature corrosion resistance.

[0122] Already at very low magnesium and / or calcium contents, the workability is improved by binding sulfur, thereby avoiding the occurrence of low-melting NiS eutectic mixtures. A minimum content of 0.0001% for magnesium and / or calcium is therefore required. At too high a content, Ni-Mg or Ni-Ca intermetallic phases may occur, which significantly impairs the workability. The magnesium and / or calcium contents are therefore limited to a maximum of 0.05%.

[0123] For good creep resistance, a minimum content of 0.015% carbon is required. Carbon is limited to a maximum of 0.12%, because above this content this element reduces workability by excessive formation of primary carbides.

[0124] A minimum content of 0.001% nitrogen is required, which improves the workability and heat resistance of the material. Nitrogen is limited to a maximum of 0.150%, because this element reduces workability by forming coarse carbonitrides.

[0125] The phosphorus content should be less than 0.030%, because this surface active element impairs high temperature corrosion resistance. If the phosphorus content is too low, the cost will be high. Therefore, the phosphorus content is ≧0.001%.

[0126] To ensure the manufacturability of the alloy, the oxygen content must be less than 0.100%. If the oxygen content is too low, the cost will be high. Therefore, the oxygen content is ≧0.0001%.

[0127] The sulfur content should be controlled as low as possible, since this surface active element impairs the high temperature corrosion resistance. Therefore, it is set at a maximum of 0.010% sulfur.

[0128] Molybdenum is limited to less than 1.0% because this element reduces high temperature corrosion resistance.

[0129] Tungsten is limited to less than 1.0% because this element also reduces high temperature corrosion resistance.

[0130] Cobalt may be present in this alloy at up to 1.0%. Higher concentrations reduce high-temperature corrosion resistance.

[0131] Copper is limited to less than 0.5% because this element reduces high temperature corrosion resistance.

[0132] In order to exhibit sufficient resistance in highly corrosive environments, such as carburizing and sulfiding and chlorinating environments, the following relationship between nickel, silicon and aluminum is required: Fc=-1.2+0.29×Ni-4.6×Si-4.4×Al≦2.5 (1a) must be satisfied, where Ni, Si and Al are the concentrations of the corresponding elements in mass %. The limitations on Fc are explained in detail in the preceding text.

[0133] If necessary, the high temperature corrosion resistance can be further improved by adding oxygen-affinity elements, which are incorporated into the oxide layer where they block the diffusion paths of oxygen on the grain boundaries.

[0134] To achieve the desired hot corrosion resistance, one or more of the elements cerium, lanthanum, cerium mischmetal, yttrium, zirconium and hafnium are required in minimum contents of 0.001% each. For cost reasons, the upper limit for each element is 0.20%, with the following formula: FRE=0.714×Ce+0.720×La+1.124×Y+1.096×Zr+0.560×Hf≦0.10 (2a) must be satisfied, where Ce, La, Y, Zr and Hf are the concentrations of the corresponding elements in mass %. This formula limits the total content of the elements cerium, lanthanum, yttrium, zirconium and hafnium. Contents with FRE>1.0 may also increase the corrosion rate and impair workability.

[0135] Titanium can be added if necessary. Titanium increases high temperature strength. Above 0.50%, high temperature corrosion behavior can deteriorate, so 0.50% is the maximum.

[0136] Niobium may be added if necessary, because it also increases high temperature strength. Higher contents increase costs very significantly. Therefore, the upper limit is set at 0.20%.

[0137] If necessary, the alloy may also contain tantalum, since it also increases the high temperature strength. Higher contents increase the cost very significantly. Therefore, an upper limit of 0.20% is set. A minimum content of 0.001% is necessary to be effective.

[0138] Boron may be added to the alloy if necessary, since it improves creep resistance. Therefore, a content of at least 0.0001% should be present. At the same time, this surface active element impairs high-temperature corrosion resistance. Therefore, a maximum of 0.008% boron is set.

[0139] By necessity, vanadium is limited to a maximum of 0.50%, since this element reduces high-temperature corrosion resistance.

[0140] Where necessary, lead is limited to a maximum of 0.002%, since this element reduces high-temperature corrosion resistance. The same applies to zinc and tin.

[0141] Too small a particle size, below 5 μm, should be avoided as it will lead to poor flow behavior, whereas too large a particle size, above 250 μm, will lead to poor behavior during additive manufacturing.

[0142] 2g / cm 2 A bulk density that is too low leads to poor behavior during additive manufacturing. 3 The maximum bulk density of is given by the density of the alloy.

[0143] [Table 1]

[0144] [Table 2]

[0145] [Table 3a]

[0146] [Table 3b]

[0147] [Table 4]

[0148] Description of the drawings Figure 1: Corrosion attack depth for various alloys after 2100 hours aging in the Prenflo pilot facility in H2S-containing gas as a function of temperature.

Claims

1. Use of a nickel-iron-chromium alloy having excellent high-temperature corrosion resistance as a powder, said powder consisting of spherical particles having a size of 5 to 250 μm, said alloy comprising (in mass %): 35.0 to 38% nickel, 26.0 to 30.0% chromium, >0.7-1.50% silicon; 0.40 to 1.30% Aluminum, 0.00 to 1.0% manganese, 0.0001-0.05% each of magnesium and / or calcium, 0.015 to 0.12% carbon, 0.001 to 0.150% nitrogen, 0.001 to 0.030% phosphorus, 0.0001 to 0.100% oxygen, Maximum 0.010% sulfur, less than 1.0% molybdenum, less than 1.0% Cobalt, less than 0.5% copper, less than 1.0% tungsten, The balance is iron and normal process impurities. Contains the following relations: Fc=-1.2+0.29×Ni-4.6×Si-4.4×Al≦2.5 (1a) must be satisfied, where Ni, Si and Al are the concentrations in mass % of the corresponding elements. The above uses.

2. 2. Use according to claim 1, having a nickel content of more than 35.0% and less than 38.0%.

3. 3. Use according to claim 1 or 2, having a chromium content of more than 26.0% to 30.0%.

4. 4. Use according to any one of claims 1 to 3, having an aluminium content of 0.50% or more or between 0.50% and less than 1.30%.

5. 5. Use according to any one of claims 1 to 4, having a residual iron content of 28.0% or greater than 28.0% to 38.0%.

6. 0.001-0.20% each of one or more of the elements cerium, lanthanum, yttrium, zirconium and hafnium, wherein the elements have the following formula: FRE=0.714×Ce+0.720×La+1.124×Y+1.096×Zr+0.560×Hf≦0.10 (2a) 6. The use according to claim 1 , wherein Ce, La, Y, Zr and Hf are the concentrations in mass % of the corresponding elements.

7. When cerium and lanthanum are present simultaneously, cerium mischmetal (abbreviated as CeMM) is also used in a content of 0.001 to 0.20%, where FRE is: FRE=0.716×CeMM+1.124×Y+1.096×Zr+0.560×Hf≦0.10 (3a) 7. The use according to claim 1, wherein CeMM, Y, Zr and Hf are the concentrations in mass % of the corresponding elements.

8. 8. Use according to any one of claims 1 to 7, optionally having a titanium content of 0.0 to 0.50%.

9. 9. Use according to any one of claims 1 to 8, optionally with a niobium content and / or a tantalum content of 0.0 to 0.50%, respectively.

10. 10. Use according to any one of claims 1 to 9, optionally having a boron content of 0.0001 to 0.008%.

11. 11. Use according to any one of claims 1 to 10, further optionally containing up to 0.50% vanadium.

12. 12. Use according to any one of claims 1 to 11, in which the impurity contents are adjusted to max. 0.002% lead, max. 0.002% tin, max. 0.002% zinc.

13. 13. The use according to any one of claims 1 to 12, wherein the powder is produced using a Vacuum Inert Gas Atomizer (VIGA).

14. 14. Use according to any one of claims 1 to 13 for any manufacturing method using a powder for producing a component or a layer on a component.

15. 15. Use according to any one of claims 1 to 14 for additive manufacturing.

16. 16. Use according to any one of claims 1 to 15 as or in a component in the chemical industry.

17. 16. Use according to any one of claims 1 to 15 as or in a component in a waste incineration or pyrolysis plant.

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