Nickel-based alloys for pipeline pipes

Abstract

The present invention relates to an alloy having the following composition by weight: 16.5%≤Cr≤25.0%; 11.0%≤Mo≤18.0%; 2.0%≤W≤7.0%; Fe≤1.0%; Mo+W≤‑0.5x(Cr+Fe)+30%; Mo+W≥‑0.5x(Cr+Fe)+25%; Ti+Ta≤0.80%; 0.01%≤Si≤0.75%; 0.01%≤Al≤0.35%; 0.01%≤Mn≤0.35%; C a≤0.005%; Mg≤0.005%; Nb≤0.01%; 0.001%≤C≤0.05%; 0.001%≤N≤0.05%; S≤0.003%; P≤0.005%; Optionally, 0.0010%≤rare earth≤0.015%, in the presence of rare earth in a content of 0.0010% to 0.015%, the silicon content is less than or equal to 0.25%, and the rest is nickel and unavoidable impurities generated by manufacturing, and the nickel content is greater than or equal to 54%.

Description

Technical Field

[0001] The present invention relates to a nickel-based alloy intended to be used in particular in the fields of petrochemicals and the extraction of petroleum products, and more particularly as part of the manufacture of pipeline pipes for the transport of gas or oil. Background Art

[0002] The extraction of gas and oil requires laying pipelines in the ocean. For reasons of productivity and economic benefits, it is hoped that the pipeline can be laid at a laying speed of about 2 km / day. There are currently three technologies that meet such productivity requirements:

[0003] S-lay technique: Pipe segments, usually 9m or 12m long, are fabricated on shore in units called spool bases and then transported offshore to be butt welded horizontally on barges. This laying is called S-lay to remind the shape of the pipeline before it touches the seabed. S-lay technique is applicable to seabeds less than 2000m.

[0004] J-lay technology: J-lay technology is more recent and applicable to deep water (2000m to 4000m). The pipe sections are welded together offshore on a vertical barge (with a small angle) and have a J-shape before touching the seabed.

[0005] R-lay technology: The recent R-lay technology is dedicated to small diameter pipelines and not very deep water. The pipeline line is welded as a whole on land, then wound on wheels for transportation at sea, and then unrolled on it by a special barge. R-lay technology is the most efficient.

[0006] Such laying techniques impose mechanical stresses on the pipeline, in particular on the orbital welds between the pipeline sections, in particular under the effect of the bending of the pipeline during laying and under the effect of the weight of the pipeline before contacting the seabed. Therefore, the pipeline, in particular the welds, must be designed to withstand such stresses to avoid deformation of the pipeline during the laying phase.

[0007] In addition to the requirements for laying speed, it is also necessary to increase the laying depth in search of still usable sediments. The laying depth can reach about 2500 meters to 3000 meters deep. This increase in laying depth increases the mechanical stresses imposed on the pipeline, so it is necessary to use carbon steel with increasingly higher mechanical properties.

[0008] The pipe sections used are usually manufactured in a workshop by rolling steel plates and then longitudinally welding the edges of the plates by the MIG / MAG process with a steel filler wire whose composition is chosen according to the grade of the plate. The wall thickness of the pipe sections is usually about 25 mm and their diameter is comprised between 25 cm and 130 cm.

[0009] According to another alternative, and depending on the application, the pipe segments are manufactured by extrusion of a billet. The pipe segments and the pipes obtained by orbital welding of the pipe segments are in this case devoid of any longitudinal welds (seamless pipes).

[0010] For steel grades X56, X60, X65, X70 or X80 that can be used to make pipe sections, the mechanical strength of the pipe sections specified according to the steel grade is as follows according to API specification 5L. The steel grade corresponds to the yield strength of the plate in ksi.

[0011]

[0012] Steel grades X56, X60, X65, X70 or X80 are defined in the American Petroleum Institute's "API Specification 5L" document, 45th edition, December 2012.

[0013] In the case of pipe sections comprising longitudinal welds, during the manufacture of the sections, it is sought to obtain welds having mechanical properties equal to or greater than those of the base steel (overmatching) so as to be able to design the sections, for example defining their thickness and the grade of steel used, depending solely on the laying conditions (S, J, R) and the type of operation of the line, without having to take into account the welds.

[0014] In the absence of longitudinal welding, for example by manufacturing the pipe sections by extrusion of billets ("seamless" technology), the gauge distribution required for the longitudinal welding can be achieved ("overmatching").

[0015] After the pipe sections have been manufactured, the inner surface of the pipe sections, including any longitudinal welds, is coated by welding with a filler wire. The purpose of this coating operation is to ensure the corrosion resistance of the pipe during the transportation of more or less corrosive petroleum products. The inner coating is usually made of Made of 625 alloy. Alloy 625 has the following composition by weight:

[0016] Cr:20.0-23.0%

[0017] Fe≤5.0%

[0018] Mo: 8.0-10.0%

[0019] Nb+Ta:3.15-4.15%

[0020] C≤0.10%

[0021] Mn≤0.50%

[0022] Si≤0.50%

[0023] P≤0.002%

[0024] S≤0.015%

[0025] Al≤0.40%

[0026] Ti≤0.40%

[0027] Other elements ≤ 0.5%,

[0028] The rest is nickel and unavoidable impurities resulting from manufacturing, of which Ni ≥ 58%.

[0029] Alloy 625 is defined in Table 1 of standard AWS A5.14 / A5.14M:2018 (Specification for Nickel and Nickel-Alloy Bare Welding Electrodes and Rods), entitled "Chemical composition requirements for Nickel and Nickel-Alloy Electrodes and Rods", under the AWS classification reference ERNiCrMo-3 (number UNS N06625).

[0030] Once the pipe segments are fabricated, they are transported on barges and butt welded by orbital welding as the pipe is laid using one of the techniques described above.

[0031] Regardless of the laying technique used, the butt welds (orbital welds) formed between the pipe sections should withstand the bending stresses of the pipeline during laying and the deadweight of the pipeline before it contacts the seabed. The mechanical strength of the orbital welds is therefore of utmost importance to prevent weld deformation during the laying phase.

[0032] Typically, the following properties are sought for orbital welds between pipe segments:

[0033] Overmatching: seeks to obtain an orbital weld with a mechanical strength greater than or equal to that of the base metal, ie the steel of the pipe section. As described above for the longitudinal welds of the pipe sections, overmatching is used in the design of pipelines, in particular for defining the thickness of the pipeline and the grade of steel used, which depends on the laying conditions (S, J, R) and the type of operation of the pipeline, without necessarily taking into account the weld.

[0034] The local corrosion resistance is greater than or equal to the corrosion resistance of the coating of the pipeline section on the inside, so that the pipeline can be designed according to the requirements in terms of local corrosion resistance without taking into account the presence of orbital welds.

[0035] Throughout this specification, localized corrosion refers to corrosion that may result from a pitting mechanism.

[0036] To meet all the above requirements, we propose to produce orbital welds where the root pass at the coating is made using 625 alloy filler wire and use the same grade of steel as the base metal to complete the weld with the filler pass. This welding technique provides good mechanical properties because it ensures a certain continuity of the materials used. On the other hand, this welding brings hot cracking, and therefore significant problems of weldability, with The problem is that the cracks are not completely satisfactory, and are related to the dilution of the 625 alloy. Such a solution is therefore not completely satisfactory. In particular, cracks that occur during welding must be repaired, which incurs considerable additional costs. Furthermore, if the cracks are not repaired, they carry the risk of causing a pipe rupture during operation.

[0037] We are also advised to use The entire weld is made with a single welding wire made of 625 alloy. This welding solution is in fact economical. In addition, the welding does not cause any hot cracking problems and leads to corrosion resistance comparable to the resistance of the coating. In addition, the welding is widely used for welding pipes up to X56 or even X60 grade. However, it is no longer suitable for higher grades of steel (X65, X70 and X80). However, the aforementioned requirements, more particularly in terms of laying speed and depth, increasingly require the use of steel grades higher than X60 grade, in particular X65 grade steel or even X70 grade steel. Summary of the invention

[0038] The object of the present invention is therefore to overcome the above-mentioned disadvantages and to provide an alloy which can be used as a filler material for the manufacture of pipeline pipes intended for the transportation of oil or gas at a high production rate, in particular of about 2 km / day, and which is suitable for laying in deep water, offshore, in particular down to a depth of about 3000 m.

[0039] Laying of pipelines at depths down to about 3000 m and at high laying rates requires the use of steels with very good mechanical properties. Preferably, with regard to the mechanical properties of the welded assembly, it is sought to obtain, at minimum: a yield strength Rp greater than or equal to 500 MPa 0.2 and greater than or equal to 100 J / cm 2 KCV rebound resilience, and advantageously, a yield strength Rp greater than or equal to 550 MPa 0.2 and / or greater than or equal to 120 J / cm 2 KCV rebound.

[0040] In addition, the use of pipes as pipelines for transporting oil or gas requires the filler material to have good corrosion resistance and good weldability. More specifically, it is sought that the local corrosion resistance and weldability are greater than or equal to Local corrosion resistance and weldability of 625 alloy.

[0041] To this end, the present invention relates to an alloy having the following weight composition:

[0042] 16.5%≤Cr≤25.0%

[0043] 11.0%≤Mo≤18.0%

[0044] 2.0% ≤ W ≤ 7.0%

[0045] Fe≤1.0%

[0046] Mo+W≤-0.5x(Cr+Fe)+30%

[0047] Mo+W≥-0.5x(Cr+Fe)+25%

[0048] Ti+Ta≤0.80%

[0049] 0.01%≤Si≤0.75%

[0050] 0.01%≤Al≤0.35%

[0051] 0.01%≤Mn≤0.35%

[0052] Ca≤0.005%

[0053] Mg≤0.005%

[0054] Nb≤0.01%

[0055] 0.001%≤C≤0.05%

[0056] 0.001%≤N≤0.05%

[0057] S≤0.003%

[0058] P≤0.005%

[0059] Optionally, 0.0010%≤rare earth≤0.015%, in the case where rare earth is present in an amount of 0.0010% to 0.015%, the silicon content is less than or equal to 0.25%,

[0060] The remainder is nickel and unavoidable impurities resulting from manufacturing, with the nickel content being greater than or equal to 54%.

[0061] The alloy according to the invention may comprise one or more of the following features, taken alone or in any technically possible combination:

[0062] Iron content less than or equal to 0.5%;

[0063] The rare earth is selected from yttrium, cerium and lanthanum and mixtures thereof; and

[0064] The rare earth is selected from yttrium, or a mixture of cerium and lanthanum.

[0065] The invention also relates to a coated component comprising a substrate made of a base material, which is a metallic material, preferably carbon steel, and for example X56, X60, X65 or X70 steel, and a coating made of the alloy described above.

[0066] According to a particular embodiment, the coated component is a pipe segment.

[0067] The present invention also relates to a filler wire made from the alloy described above.

[0068] The present invention relates to a method for manufacturing a filler wire as described above, comprising the following steps:

[0069] Supply of semi-finished products made of alloys as described above;

[0070] Thermal transformation of the semi-finished product to form an intermediate welding wire; and

[0071] The intermediate welding wire is transformed into a filler welding wire having a diameter smaller than a diameter of the intermediate welding wire, the transformation comprising a drawing step.

[0072] The invention also relates to a welded assembly comprising at least two parts of a component, each part being made of a base material, the parts of each component being joined together by a weld obtained with a filler wire as described above, the base material being selected from an iron-nickel alloy (e.g., Fe-9Ni), a nickel-based alloy (e.g., C-276, C-4 or 22) and a carbon steel (e.g., X56, X60, X65 or X70 steel).

[0073] The welded assembly according to the invention may also comprise one or more of the following features, taken alone or in any technically possible combination:

[0074] The welded assembly forms a pipe section comprising a metal sheet bent into a tubular shape, the longitudinal edges of the metal sheet forming respective portions of the respective components joined together by the weld;

[0075] The pipe section is provided with a coating made of an alloy as described above on at least a portion, preferably all, of its inner surface; and

[0076] The welded assembly forms a pipe comprising at least two pipe segments, the pipe segments forming part of a component, and the weld extends along the circumference of the pipe, the pipe segments preferably being pipe segments as described above.

[0077] The invention also relates to a method for producing a welded assembly, which method comprises welding together two parts of a component by means of a filler wire as described above, the welding being in particular arc welding.

[0078] The manufacturing method according to the above assembly may also have one or more of the following features, taken individually or in any technically conceivable combination:

[0079] The welding step is a step of welding the longitudinal edges of the metal sheets together, the welding is preferably a longitudinal butt welding; and

[0080] The method comprises the following consecutive steps prior to the welding step:

[0081] supplying a first pipe segment and a second pipe segment, each of the first pipe segment and the second pipe segment extending along a longitudinal axis and being made of the base material;

[0082] Positioning the first pipe segment and the second pipe segment such that a longitudinal end of the first pipe segment is arranged to face a longitudinal end of the second pipe segment along a longitudinal axis of the first pipe segment and the second pipe segment; and

[0083] The welding step is a step of welding together the two longitudinal ends facing the first pipe section and the second pipe section, and the welding is preferably an orbital butt welding.

[0084] The invention also relates to a component or a part of a component made of an alloy as described above, which component or part of a component is produced by additive manufacturing.

[0085] The additive manufacturing process more particularly uses a filler wire made of an alloy as described above and / or a powder made of an alloy as described above as filler material.

[0086] An additive manufacturing process is an additive manufacturing process which uses, for example, an electric arc, a laser beam and / or an electron beam as an energy source for melting the filler material.

[0087] For example, the additive manufacturing process is a wire-arc, wire-laser, electron beam-wire process or a hybrid additive manufacturing process combining wire-arc and laser-powder or wire-arc and wire-laser technologies.

[0088] The present invention also relates to a method for manufacturing a component or a part of a component, which comprises the step of manufacturing the component or the part of the component by a metal additive manufacturing process, wherein the metal additive manufacturing process uses a filler wire made of an alloy as described above and / or a powder made of an alloy as described above as filler material.

[0089] An additive manufacturing process is an additive manufacturing process which uses, for example, an electric arc, a laser beam and / or an electron beam as an energy source for melting the filler material.

[0090] For example, the additive manufacturing process is a wire-arc, wire-laser, electron beam-wire process or a hybrid additive manufacturing process combining wire-arc and laser-powder or wire-arc and wire-laser technologies.

[0091] The present invention also relates to the use of the filler wire as described above:

[0092] Used as a welding filler wire for welding two parts of a component together, the welding filler wire being made of a base material which is an iron-nickel alloy such as Fe-9Ni, a nickel-based alloy such as C-276, C-4 or 22, or carbon steel, and in particular X56, X60, X65 or X70 steel; and / or

[0093] Used as a hardfacing welding wire for producing a coating on a component or part of a component, which is made of a metallic base material, preferably a carbon steel, such as X56, X60, X65 or X70 steel; and / or

[0094] For use as filler wire in metal additive manufacturing processes.

[0095] The invention also relates to a metal powder made from an alloy as described above.

[0096] The invention also relates to a method for producing a metal powder made of an alloy as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0097] The invention will be better understood from a reading of the following description, given by way of example only, and with reference to the accompanying drawings, in which:

[0098] Figure 1 is a schematic cross-sectional view of a welded assembly according to the present invention;

[0099] Figure 2 is a schematic perspective view of a pipe section according to the present invention;

[0100] Figure 3 is a schematic top view of a metal sheet used in carrying out a process for manufacturing a pipe segment;

[0101] Figure 4 is a schematic perspective view of a pipeline according to the present invention;

[0102] Figure 5 is a schematic perspective view of a component coated according to the present invention; and

[0103] Figure 6 is a schematic perspective view of a component produced by additive manufacturing according to the invention. DETAILED DESCRIPTION

[0104] In the following description, all contents are expressed in weight percentage.

[0105] The alloy according to the invention has the following composition by weight:

[0106] 16.5%≤Cr≤25.0%

[0107] 11.0%≤Mo≤18.0%

[0108] 2.0% ≤ W ≤ 7.0%

[0109] Fe≤1.0%

[0110] Mo+W≤-0.5×(Cr+Fe)+30%

[0111] Mo+W≥-0.5×(Cr+Fe)+25%

[0112] Ti+Ta≤0.80%

[0113] 0.01%≤Si≤0.75%

[0114] 0.01%≤Al≤0.35%

[0115] 0.01%≤Mn≤0.35%

[0116] Ca≤0.005%

[0117] Mg≤0.005%

[0118] Nb≤0.01%

[0119] 0.001%≤C≤0.05%

[0120] 0.001%≤N≤0.05%

[0121] S≤0.003%

[0122] P≤0.005%

[0123] Optionally, 0.0010%≤rare earth≤0.015%, in the case where rare earth is present in an amount of 0.0010% to 0.015%, the silicon content is less than or equal to 0.25%,

[0124] The remainder is nickel and unavoidable impurities resulting from manufacturing, with the nickel content being greater than or equal to 54%.

[0125] Unavoidable impurities resulting from manufacturing refer to elements present in the raw materials used to make the alloy or from the equipment used to make the alloy (e.g. refractory materials from a furnace). Such residual elements have no metallurgical effect on the alloy.

[0126] In the alloy, a nickel content greater than or equal to 54 wt. % provides good ductility of the matrix and good stress corrosion resistance.

[0127] Chromium provides good generalized corrosion resistance and improves the mechanical properties of the alloy when the content is 16.5 wt. % to 25.0 wt. %. More specifically, the inventors have found that when the chromium content is less than 16.5 wt. %, the generalized corrosion resistance is insufficient. In addition, a chromium content greater than 25.0 wt. % leads to the precipitation of the sigma phase, which is associated with a loss of ductility and an increased sensitivity to hot cracking, and thus leads to a reduction in the mechanical properties of the alloy.

[0128] Preferably, the chromium content is greater than or equal to 17.0% and less than or equal to 23.0%.

[0129] Molybdenum present in an amount of 11.0 wt. % to 18.0 wt. % improves localized corrosion resistance.

[0130] Furthermore, molybdenum significantly improves the mechanical properties. The inventors have found that for molybdenum contents of less than 11.0 wt. %, localized corrosion resistance and mechanical properties are insufficient, while molybdenum contents exceeding 18% lead to undesired phase precipitation, resulting in loss of ductility and increased sensitivity to hot cracking.

[0131] Preferably, the molybdenum content is greater than or equal to 11.5% and less than or equal to 16.5%.

[0132] The tungsten content is between 2.0 wt. % and 7.0 wt. %. The presence of tungsten in such a content also improves local corrosion resistance. In addition, tungsten improves mechanical properties. The inventors have found that when the tungsten content is less than 2.0%, the local corrosion resistance is insufficient. Moreover, a tungsten content greater than 7.0% leads to the precipitation of undesirable phases, resulting in a loss of ductility and an increased sensitivity to hot cracking.

[0133] The iron content is less than or equal to 1.0 wt%. The addition of iron reduces the resistance to generalized corrosion. The iron content is less than or equal to 1.0 wt%, allowing the alloy to be produced from scrap containing residual iron content, which reduces manufacturing costs. When the iron content is greater than 1.0 wt%, iron also enhances the precipitation of undesirable phases, resulting in a loss of ductility and an increase in sensitivity to hot cracking.

[0134] Preferably, the iron content is less than or equal to 0.5% by weight.

[0135] The sum of the contents of titanium and tantalum is less than or equal to 0.80 wt. %. The presence of titanium and tantalum in the required contents greatly improves the mechanical properties, but their low solubility in Ni-Cr alloys produces precipitation of undesirable phases. Therefore, the content of these elements must be limited to low levels. However, they contribute to the deoxidation of the alloy during manufacturing. The inventors have found that when Ti+Ta is greater than 0.80 wt. %, precipitation of undesirable phases is observed, resulting in loss of ductility and increased sensitivity to hot cracking.

[0136] According to the invention, Mo+W≤-0.5×(Cr+Fe)+30 wt. %. The inventors have observed that satisfying the above relationship leads to satisfactory ductility (in particular, as indicated by the fracture energy KCV≥100 J / cm 2 ) and good weldability (indicated by a total crack length less than or equal to 20 mm).

[0137] Fracture energy KCV in J / cm 2 The fracture energy KCV reflects the resilience of the component. It is determined, for example, by a resilience test carried out at room temperature in accordance with standard NFEN ISO 148-1 (January 2011).

[0138] The crack length is determined in particular by a Varestraint test at 3.2% plastic deformation according to European Standard FD CEN ISO / TR 17641-3 (November 2005).

[0139] Furthermore, Mo+W≥-0.5×(Cr+Fe)+25 wt %. The present inventors have found that satisfying the above relationship leads to satisfactory mechanical strength, in particular a yield strength Rp greater than or equal to 500 MPa. 0.2 .

[0140] At the above levels, silicon and aluminum enhance deoxidation and manganese enhances desulfurization during alloy manufacture.

[0141] The content of calcium and magnesium in the alloy is limited to 0.005% by weight each so as not to reduce weldability. More particularly, the content of calcium and magnesium is limited so as not to reduce the quality of the weld, in particular by forming slag on the surface, which can cause instabilities in the arc and the bath.

[0142] The niobium content is less than or equal to 0.01% by weight. The niobium content in the alloy is limited so as not to reduce the hot cracking resistance. In particular, niobium segregates strongly in the interdendritic spaces and enhances the precipitation of undesirable phases.

[0143] The alloy also contains 0.001-0.05 wt% carbon and nitrogen. Carbon is controlled in order to facilitate deoxidation during alloy manufacturing. In addition, carbon and nitrogen also ensure the refinement of the microstructure through the precipitation of Ti-(C,N) carbonitrides (if they are associated with the addition of titanium).

[0144] In order to improve the hot cracking resistance, the contents of S and P are limited as much as possible. In the above alloy, the contents are less than or equal to 0.003 wt. % and 0.005 wt. %, respectively.

[0145] Optionally, the alloy contains rare earths in an amount of 0.0010 to 0.015 wt. %. Rare earths trap sulfur and residual oxygen, and when welding a base metal containing a higher residual S+O content than the welding wire, rare earths improve hot cracking resistance. However, in amounts greater than 0.015%, they enhance the precipitation of eutectic phases with a low melting point, especially in the presence of silicon, which leads to a loss of ductility and an increased sensitivity to hot cracking.

[0146] The rare earth is preferably selected from yttrium, cerium and lanthanum, or from mixtures of said elements.

[0147] According to one example, the rare earth consists of yttrium, in which case the alloy contains 0.0010 wt. % to 0.015 wt. % yttrium.

[0148] According to one variant, the rare earths consist of a mixture of cerium and lanthanum. In this case, the content of Ce+La in the alloy is between 0.0010% and 0.015% by weight.

[0149] In the case of a rare earth content of 0.0010% to 0.015% by weight, the silicon content is limited to 0.25% by weight, preferably to 0.20% by weight. In this case, the silicon content is therefore 0.01% to 0.25% by weight, preferably 0.01 to 0.20% by weight. In fact, silicon enhances the formation of rare earth-containing phases, which reduces the availability of rare earth for capturing residual sulfur and oxygen.

[0150] The alloy according to the invention has a yield strength Rp of 500 MPa to 600 MPa. 0.2 and greater than or equal to 100 J / cm 2 The KCV resilience can be used to obtain ductile welds that exhibit overmatched mechanical properties compared to the base material made of X56, X60, X65 or X70 steel.

[0151] As mentioned above, steel grades X56, X60, X65, X70 or X80 are defined in the American Petroleum Institute API Specification 5L document, 45th edition, December 2012.

[0152] Furthermore, the alloy according to the invention has:

[0153] Good corrosion resistance, especially greater than or equal to the contrast Localized corrosion resistance of 625 alloy;

[0154] Solderability greater than or equal to comparison Weldability of 625 alloy.

[0155] Therefore, for a design having a yield strength Rp greater than or equal to 500 MPa 0.2 and greater than or equal to 100 J / cm 2 The KCV resilience and, in particular, the design of welded joints containing X56, X60, X65 and X70 steels as base material, the properties of longitudinal and / or orbital welds can be ignored.

[0156] Considering its properties, the alloy according to the invention is therefore particularly suitable for use as a filling material for producing pipeline pipes intended to transport oil or gas and suitable for laying in the deep sea, in particular in international waters down to a depth of about 3000 m, at a high production rate, in particular of about 2 km / day.

[0157] Therefore, this alloy can be advantageously used as filler material for longitudinal and / or orbital welds of pipeline pipes made of X56, X60, X65 or X70 steels and intended to be laid at considerable depths, for example down to depths of 3000 m and for high laying rates.

[0158] Given its good corrosion resistance, the alloy can also be used to produce internal coatings designed to improve the corrosion resistance of such pipes.

[0159] The alloy according to the invention can be obtained by any suitable method known to a person skilled in the art.

[0160] For example, in a first step, the starting materials are fed into an electric arc furnace. The starting materials are selected to obtain an alloy containing less than 1.0% by weight of iron. The above are especially new materials. The starting materials are then melted in the electric arc furnace and then subjected to vacuum oxygen decarburization (VOD) by conventional methods to obtain:

[0161] Decarburization is carried out by blowing oxygen and applying a vacuum (about a few mbar);

[0162] Deoxygenation and desulfurization under lime slag; and

[0163] Adjustment of reducing elements such as Ti and Al.

[0164] The present invention also relates to a filler wire made of an alloy having a composition as described above.

[0165] This filler wire is particularly suitable for TIG or plasma welding processes using filler wire, or MIG / MAG welding processes.

[0166] For example, filler wires are intended for use as:

[0167] A welding filler wire for welding two parts of a component together, the welding filler wire being made of a base material, in particular an iron-nickel alloy, such as Fe-9Ni, i.e. containing a nickel content of 5 to 10% by weight, or a nickel-based alloy, such as C-276, C-4 or 22, or a carbon steel, in particular X56, X60, X65 or X70 steel; and / or

[0168] Surface hardening welding wire for producing coatings, in particular on components or parts of components made of a base material, which is carbon steel, and in particular X56, X60, X65 or X70 steel.

[0169] Alloy C-276 is defined in Table 1 of AWS A5.14 / A5.14M:2018 (Specification for Nickel and Nickel-Alloy bare Welding Electrodes and Rods), entitled “Chemical composition requirements for Nickel and Nickel-Alloy Electrodes and Rods,” under the AWS classification reference ERNiCrMo-4 (number UNS N10276).

[0170] Alloy C-4 is defined in Table 1 of standard AWS A5.14 / A5.14M:2018 (Specification for Nickel and Nickel-Alloy bare Welding Electrodes and Rods), entitled “Chemical composition requirements for Nickel and Nickel-Alloy Electrodes and Rods,” under AWS classification reference ERNiCrMo-7 (number UNS N06455).

[0171] Alloy 22 is defined in Table 1 of AWS A5.14 / A5.14M:2018 (Specification for Nickel and Nickel-Alloy bare Welding Electrodes and Rods), entitled “Chemical composition requirements for Nickel and Nickel-Alloy Electrodes and Rods,” under the AWS classification reference ERNiCrMo-10 (number UNS N06022).

[0172] The component or the part of the component is in particular a pipe section, a tube and / or a metal sheet or a part of a metal sheet made of a base material.

[0173] For example, the filler wire is also intended for use as a filler wire in a metal additive manufacturing process.

[0174] An additive manufacturing process is, for example, an additive manufacturing process that uses an electric arc, a laser beam and / or an electron beam as an energy source for melting the filler wire.

[0175] The additive manufacturing process is in particular a directed energy deposition additive manufacturing process. During this process, a filler material is deposited, in particular via a nozzle, and immediately melted by concentrated thermal energy, in particular a laser beam, an electron beam and / or an electric arc.

[0176] As an example, the additive manufacturing process is a wire-arc (WAAM or "wire arc additive manufacturing"), a wire-laser, an electron beam-wire ("electron beam freeform manufacturing" or "electron beam additive manufacturing") process, or a hybrid additive manufacturing process combining wire-arc and laser powder technology or wire-arc and wire-laser technology.

[0177] In the case of a hybrid wire-arc and laser-powder process, the powder used has the same composition as the welding wire.

[0178] Such a powder, whose particle size distribution after sieving is between 20 μm and 150 μm, is obtained, for example, from a filler wire according to the invention by means of a plasma atomization technique. Preferably, the filler wire used for making the powder has a diameter of about 3 mm.

[0179] The particle size distribution of the powder is determined in particular by the following measuring method. The powder batch is divided into a plurality of powder particle size distributions by means of an ultrasonically vibrating stainless steel sieve. The analysis of the particle size distribution of the sieved powder is carried out according to the ASTM B 214-07 standard. Sieving is used to obtain 5 particle size classes: <20 μm, 20 μm-45 μm, 45 μm-75 μm, 75 μm-105 μm, >105 μm.

[0180] The plasma atomization technique for producing powder from welding wire is known per se and will therefore not be described in detail.

[0181] The component or part of the component is used in particular for the aviation, transport or energy markets. The component or part of the component forms, for example, a housing, a frame, a pipe with a complex shape, a valve, an attachment lug or a part of a component with a specific function. As an example, such a part of the component forms a heat exchanger element containing, for example, a channel for the circulation of a fluid, which channel is formed by additive manufacturing on a supporting part, which is, for example, made of a material different from the material of the heat exchanger element.

[0182] The invention also relates to a method for producing a filler wire made of an alloy as described above.

[0183] The method comprises, in a first step, supplying a semi-finished product made of said alloy. For this purpose, the alloy is cast into ingots or directly into billets, in particular by continuous casting, in particular spin casting. The semi-finished product obtained at the end of this step is thus advantageously an ingot or billet and has, for example, a diameter comprised between 130 and 230 mm, and more particularly equal to about 150 mm.

[0184] The semi-finished product is then transformed by thermal transformation to form an intermediate welding wire.

[0185] In particular, during the thermal transformation step, the semi-finished product, ie in particular an ingot or a billet, is heated to a temperature of 1180° C. to 1220° C., in particular in a gas-fired furnace.

[0186] They are then subjected to hot roughing to reduce their cross section, for example by giving the semi-finished product a square cross section with a side length of about 100 to 200 mm. A semi-finished product with reduced cross section is thus obtained. The length of the semi-finished product with reduced cross section is in particular between 10 and 20 meters.

[0187] The semi-finished product with reduced cross section is then again subjected to hot deformation at a temperature between 1050° C. and 1150° C. in order to obtain an intermediate welding wire. The intermediate welding wire may in particular be a mechanical wire. The wire has, for example, a diameter comprised between 5 mm and 21 mm, and in particular approximately equal to 5.5 mm. Advantageously, during this step, the intermediate welding wire is produced by hot rolling on a wire rolling train.

[0188] Optionally, after the heat treatment in the gas furnace, the intermediate wire is then subjected to superquenching in a bath at a temperature of 1150° C. to 1220° C. for a period of time of 60 minutes to 120 minutes.

[0189] The intermediate wire is then pickled and then wound into a coil.

[0190] Optionally, in order to obtain a filler wire, the intermediate wire thus obtained is drawn by a wire drawing device of known type. The diameter of the filler wire is smaller than the diameter of the starting wire. Its diameter is in particular comprised between 0.5 mm and 3.5 mm. Its diameter is advantageously comprised between 0.8 mm and 2.4 mm.

[0191] Depending on the final diameter to be achieved, the wire drawing step comprises one or more wire drawing passes, preferably with annealing between two consecutive wire drawing passes. Annealing is carried out, for example, at a temperature of about 1150° C. in a reducing atmosphere during the pass.

[0192] After the wire drawing step, the surface of the drawn wire is preferably cleaned and then the drawn wire is wound.

[0193] The wire drawing pass is a cold pass.

[0194] Any other method known to the person skilled in the art for producing the alloy according to the invention and for producing finished products made of the alloy can be used for this purpose.

[0195] The invention also relates to a welded assembly 1 comprising at least two parts of a component 3 made of a base metal joined together by a weld 5 obtained with a filler wire as described above. Figure 1 It is schematically shown in FIG.

[0196] The degree of dilution of the welding wire during welding is, for example, comprised between 1% and 10%, and is in particular approximately equal to 5%.

[0197] Throughout the text, "parts of components" that are welded together refer to the case where the parts welded together belong to two initially separate components, as well as the case where the components are two parts of the same component folded on themselves, such as two longitudinal edges of a metal sheet that are welded to form a tube.

[0198] The base metal is in particular a carbon steel, such as X56, X60, X65 or X70 steel, or an iron-nickel alloy, such as Fe-9%Ni, ie a nickel content of 5 to 10% by weight, or a nickel-based alloy, such as C-276, C-4 or 22.

[0199] The invention also relates to a welding method for welding together at least two parts of a component 3 made of a base metal as defined above, in order to produce a Figure 1 The welded assembly 5 is shown.

[0200] In a first step, a filler wire as described above is provided. Portions of a component 12 made of a base metal to be welded together by a welding process are also provided.

[0201] The parts of the component 12 are then welded together using the filler wire as a welding filler wire. In this step, butt welding is preferably performed.

[0202] The welding step may comprise one or more welding passes. Typically, the welding step comprises a first welding pass, referred to as the root pass, followed by one or more additional welding passes, referred to as filler passes. All welding passes are performed by using a filler wire according to the invention as filler wire, as described above. The dilution of the filler wire is therefore limited to the dilution of the molten base metal produced by the welding.

[0203] The degree of dilution of the welding wire during welding is, for example, comprised between 1% and 10%, and is in particular approximately equal to 5%.

[0204] The welding is performed, for example, by arc welding, for example by plasma welding with a filler wire, by MIG (metal inert gas) welding or by MIG / MAG (metal active gas) welding.

[0205] According to one embodiment, Figure 2 As shown, the welded assembly 1 is a tube section 7 comprising a metal sheet 9 folded into a tube, the longitudinal edges 12 of which are connected together by a weld 15 obtained by a filler wire as described above. In this case, the portion of the component 3 comprises the longitudinal edges 12 of the metal sheet 9.

[0206] The wall of the tube section 5 has, for example, a thickness comprised between 3 mm and 60 mm.

[0207] The pipe section 5 is particularly used for conveying corrosive products, more particularly gas or oil. More particularly, it is used to form a part of a pipeline, particularly laid on the seabed, more particularly at a depth of up to 3000m.

[0208] A further subject matter of the invention is a method for producing such a pipe section 5 .

[0209] The method comprises providing a metal plate 9 made of a base metal. Figure 3 The metal plate 9 extends along a longitudinal direction L and has longitudinal edges 12 substantially parallel to the longitudinal direction L. For example, the metal plate has a thickness comprised between 3 mm and 60 mm.

[0210] The method also comprises a step of folding the metal sheet 9 so that the two longitudinal edges 12 face each other, followed by a step of welding the two longitudinal edges 12 facing each other using the welding method defined above. In this case, the part of the component 3 described in the context of the welding process comprises the longitudinal edges 12 of the metal sheet 9.

[0211] The weld produced in this step is a longitudinal weld. Preferably, the weld is a butt weld.

[0212] At the end of this process, a pipe section 7 is obtained, such as Figure 2 In which a metal sheet 9 is folded into the shape of a pipe and the longitudinal edges 12 of the metal sheet 9 are joined together by a weld 15 obtained by a filler wire as defined above.

[0213] According to another embodiment, Figure 4 As shown, the welded assembly is a pipe 20, and the portions of the component 3 are pipe segments 7 connected together by welds 22 obtained by the above-mentioned filler wire. In this embodiment, the weld 22 extends along the circumference of the pipe 20 so as to connect the pipe segments 7 together.

[0214] The welding is in particular a butt welding, preferably an orbital welding.Orbital welding refers to welding produced by rotating a welding tool, more particularly a welding torch, relative to the pipe section 7 to be welded.

[0215] The wall 20 has a thickness, for example, comprised between 3 and 60 mm.

[0216] According to one embodiment, the pipe section 7 is a pipe section as described above.

[0217] According to a variant, the portion of component 3 is a tube section not comprising any longitudinal weld and obtained, for example, by extrusion of a billet.

[0218] The pipeline 20 is particularly used for conveying corrosive products, more particularly gas or oil. More particularly, it is used to form a part of a pipeline, particularly laid on the seabed, more particularly at a depth of up to 3000m.

[0219] Another subject of the invention is therefore a method for manufacturing a pipe 20 as defined above.

[0220] During this process, at least two tube sections 7 are provided. Each tube section 5 is substantially cylindrical, having an axis M and two longitudinal ends 24 spaced apart in the direction of the axis M.

[0221] The two pipe segments 7 are then positioned so that their longitudinal ends 24 are arranged facing each other in the direction of the axis M of the pipe segments, and then the longitudinal ends 24 facing the two pipe segments 7 are welded together by the welding method as described above. In this case, the part of the component 3 defined in the context of the welding process includes the longitudinal ends 24 of the pipe segments 7.

[0222] Advantageously, during this step, a butt weld is formed between the longitudinal ends 24 facing the pipe sections 7. This weld is preferably an orbital weld.

[0223] Preferably, before joining the pipe sections 7 together, the welding step comprises a step of machining chamfers at the ends 24 of the pipe sections 7 to be welded together.

[0224] The welding step is performed a number of times equal to the number of pipe sections 7 to be welded to form the pipeline 20 minus one.

[0225] According to one embodiment, the pipe section 7 is a pipe section 7 as described above.

[0226] In a variant, the method can be carried out with any type of pipe section whose longitudinal ends are made of a base metal, whatever the method of obtaining the pipe section. More particularly, the method is carried out on a pipe section that does not contain a longitudinal weld and that is more particularly obtained by billet extrusion.

[0227] The method is more particularly carried out on a barge, which is located, for example, at the location where the pipeline 20 is installed.

[0228] At the end of the welding step, a pipe 20 is obtained. The pipe 20 comprises at least two consecutive pipe sections 7 assembled together by a weld 22 made with the above-mentioned filler wire.

[0229] The present invention also relates to Figure 5 The coated component 26 shown comprises a substrate 28 made of a base material coated with a coating 30 made of the above alloy. The base material is a metallic material.

[0230] The base material is in particular carbon steel. Preferably, the base material is X56, X60 or X65 or X70 steel.

[0231] The coating 30 is more particularly applied to the substrate 28 by a process of hard surface treatment by welding with the aid of a filler wire having the composition described above.

[0232] Coating 30 more particularly has a thickness comprised between 2 mm and 20 mm.

[0233] Such a coating 30 improves the corrosion resistance of the coated part 26 , more particularly in the presence of corrosive products such as petroleum products.

[0234] The coated portion 26 is in particular a coated pipe section 7 , the coating 30 being formed on the inner wall of the pipe section 7 and in particular covering the inner wall of the pipe section 7 over the entire surface thereof, including the weld seam 12 if any.

[0235] The present invention also relates to a method for producing the coated component 26 as described above, comprising providing a substrate 28 made of a base material and then applying a coating 30 on the surface of the substrate by a weld surface hardening process using a filler wire having the above composition.

[0236] In the case where the coated portion 26 is a section of a coated pipe 7, the manufacturing method more particularly comprises a step of manufacturing the pipe section 7 by implementing the method described above, followed by a step of applying the coating 30 to the inner surface of the pipe section 7 by a process of surface hardening by welding using a filler wire having the composition described above.

[0237] The coating 30 improves the corrosion resistance of the pipe section 7, for example during the transportation of variably corrosive petroleum products.

[0238] According to a particular embodiment, the pipeline 20 described above comprises two pipe sections 7 coated with a coating 30 as described above, the two pipe sections being joined together by a weld 22 .

[0239] The present invention also relates to a method for manufacturing Figure 6 A method for manufacturing a component 40 from an alloy as described above, schematically shown in FIG. 1 , the method comprising:

[0240] supplying a filler wire made of the alloy; and

[0241] The component 40 is manufactured by a metal additive manufacturing process using a filler wire made of an alloy as described above and / or a powder made of an alloy as described above as a filler material.

[0242] An additive manufacturing process is, for example, an additive manufacturing process which uses an electric arc, a laser beam and / or an electron beam as energy source for melting the filler material.

[0243] The additive manufacturing process is in particular a directed energy deposition additive manufacturing process. During this process, a filler material is deposited, in particular via a nozzle, and is immediately melted by concentrated thermal energy, in particular a laser beam, an electron beam and / or an electric arc.

[0244] As an example, the additive manufacturing process is a wire-arc, wire-laser, electron beam-wire (“electron beam freeform manufacturing”) process or a hybrid additive manufacturing process combining wire-arc and laser powder technology or wire-arc and wire-laser.

[0245] In the case of a hybrid additive manufacturing process using a combined wire-arc and laser powder technology or wire-arc and wire-laser technology, the powder and filler wire are made of an alloy as described above.

[0246] The above-mentioned additive manufacturing process is known per se and will not be described in detail.

[0247] In the case where the filler material comprises a powder, in particular in the context of a hybrid wire-arc and laser-powder process, the process also comprises a step of supplying a powder made of an alloy as described above, before manufacturing the component 40. The powder, whose particle size distribution after sieving is between 20 μm and 150 μm, is produced, for example, by plasma atomization of a welding wire made of an alloy as described above, more particularly having a diameter of about 3 mm.

[0248] The plasma atomization process is known per se and will therefore not be described in detail.

[0249] The invention also relates to a component 40 or a portion of a component produced by metal additive manufacturing and made of an alloy as described above.

[0250] The metal additive manufacturing process more particularly uses a filler wire made of an alloy as described above and / or a powder made of an alloy as described above as filler material.

[0251] An additive manufacturing process is, for example, an additive manufacturing process which uses an electric arc, a laser beam and / or an electron beam as energy source for melting the filler material.

[0252] The additive manufacturing process is in particular a directed energy deposition additive manufacturing process. During this process, a filler material is deposited, in particular via a nozzle, and is immediately melted by concentrated thermal energy, in particular a laser beam, an electron beam and / or an electric arc.

[0253] As an example, the additive manufacturing process is a wire-arc, wire-laser, electron beam-wire (“electron beam freeform manufacturing”) process or a hybrid additive manufacturing process combining wire-arc and laser powder technology or wire-arc and wire-laser.

[0254] In the case of a hybrid additive manufacturing process using a combined wire-arc and laser powder technology or wire-arc and wire-laser technology, the powder and filler wire are made of an alloy as described above.

[0255] The component or part of a component (for example, part 40) obtained by a metal additive manufacturing process is so solidified. Therefore, the component or part of a component has a typical solidified microstructure of the nickel alloy under consideration, which generally contains columnar dendrites that grow epitaxially on top of each other and whose orientation depends on the width and thickness of the metal wall produced. In addition, the component obtained by the additive manufacturing process has a series of superimposed solidified layers due to its additive manufacturing process. Each solidified layer, obtained by solidification of deposited droplets of molten metal, melts the surface layer of the previous layer to create metallurgical continuity and thus heats the rest of the next layer. Since the layer in question is far away from the zone undergoing melting and solidification, the reheating temperatures are all lower. This specific microstructure can be observed by metallographic observations on metallographic sections of these components.

[0256] Thus, a component 40 or portion of a component produced by a metal additive manufacturing process may be distinguished from components produced by other methods, particularly from components produced by conventional metallurgy that produces a recrystallized structure having a uniform grain size.

[0257] The component 40 or the part of the component is used in particular for the aviation, transport or energy markets. The component or the part of the component forms, for example, a housing, a frame, a pipe with a complex shape, a valve, an attachment lug or a part of a component with a specific function. As an example, such a part of the component forms a heat exchanger element containing, for example, channels for the circulation of a fluid, which are formed by additive manufacturing on a supporting part, which is, for example, made of a material different from the material of the heat exchanger element.

[0258] test

[0259] In a first series of tests, the inventors carried out laboratory castings to produce ingots of the alloy having the composition as defined above and of a comparative alloy having a composition different from that described above.

[0260] The alloy was produced under vacuum, and the ingot thus produced was transformed by hot rolling to obtain strips having dimensions of 10×50×300 mm.

[0261] The alloy composition of each of the strips tested is shown in Table 1 below.

[0262] The present inventors then carried out the following tests on the thus produced planks.

[0263] On some strips, the inventors produced front and rear joining fusion lines by means of a TIG welding torch so as to form a solidified structure in the thickness of the strip comparable to that produced by TIG or MIG welding under non-dilution conditions, and sampled, tensilely and elastically tested specimens from the molten area.

[0264] Then, the inventors performed the following operations:

[0265] According to standard NF EN ISO 6892-1 (December 2019), a mechanical flat tensile test is carried out at room temperature (20°C) to measure the yield strength Rp of the above tensile specimen at 0.2% elongation at 20°C 0.2 The test results are summarized in the following Table 2, “Rp 0.2 " column.

[0266] The resilience test was carried out on the above-mentioned resilience test specimens at room temperature (20°C) according to standard NF EN ISO 148-1 (January 2011), and the impact fracture energy (expressed as KCV) was measured. The fracture energy is expressed in J / cm 2 The fracture energy reflects the resilience of the component. The test results are summarized in the "KCV" column in Table 2 below.

[0267] The inventors also measured the surface fraction of the phase precipitated in the molten zone of the strip during the solidification of the molten metal under the TIG torch. The surface fraction of the precipitated phase was determined by image analysis of the images of the strip obtained with a scanning electron microscope (SEM). In fact, the precipitated phase corresponds to the white area on the image and is detected by image processing software, which detects the white area by grayscale analysis and then determines the surface fraction occupied by the white area. The measurement results are summarized in the "FS" column of Table 2 below.

[0268] The inventors also conducted Varestraint tests on the strips without a weld line at 3.2% plastic deformation to evaluate their resistance to thermal cracking according to European Standard FD CEN ISO / TR 17641-3 (November 2005), and measured the total length of cracks generated during the test. The test results are summarized in the "L 总 Cracks".

[0269] Finally, the inventors conducted potentiometric tests to test the alloy's resistance to localized corrosion. To this end, the inventors measured the potential of the alloy at 11.9 mol.l at a pH of 5.4 and a temperature of 30°C. -1 The pitting potential V in the LiCl medium is calculated and the pitting potential is compared with The pitting potential of Inconel 625 (VInconel 625 / SCE < 120 mV) was compared, where SCE is the reference potential relative to a saturated calomel electrode.

[0270] In the following Tables 1 and 2, tests not according to the invention are underlined.

[0271]

[0272]

[0273] Table 1: Composition of the alloys tested in the first series

[0274] In the alloy of Table 1, the Al content is between 0.01% and 0.35%, the N content is between 0.001% and 0.05%, the Mg and Ca contents are less than or equal to 0.005%, and the P content is less than or equal to 0.005%. In addition, the alloy does not contain niobium.

[0275] For all alloys in Table 1, the remainder is nickel, plus impurities resulting from manufacturing.

[0276] In addition, all compositions are expressed in weight percent.

[0277]

[0278]

[0279] Table 2: Results of tests carried out on strips produced from the alloys of Table 1

[0280] Furthermore, during the potentiometric test, alloys A1 to A28 of Table 1 produced a pitting potential V greater than or equal to 150 mV relative to the reference potential of a saturated calomel electrode. Alloy 625 has better resistance to localized corrosion.

[0281] As mentioned above, preferably a combination of the following properties is sought:

[0282] Yield strength Rp greater than or equal to 500MPa 0.2 ;

[0283] Greater than or equal to 100J / cm 2 KCV rebound;

[0284] The total length of the crack is less than or equal to 20 mm;

[0285] The surface fraction FS of the precipitated phase is less than or equal to 1.5%;

[0286] Greater than or equal to Localized corrosion resistance of 625 alloy.

[0287] Among the above parameters, the total crack length represents the weldability of the alloy. The total crack length of 625 alloy is equal to 20mm, so the total crack length less than or equal to 20mm corresponds to a total crack length greater than or equal to The weldability of 625 alloy is satisfactory and therefore sufficient for the application under consideration.

[0288] These properties are obtained in the case of Examples A2 to A4, A8 to A11, A14 to A16, A19 to A21, A25 and A26, which correspond to alloys having the composition described above.

[0289] On the other hand, in the case of Comparative Examples A1, A7, A18, and A24, the yield strength Rp 0.2 Less than or equal to 500 MPa, while the KCV resilience is insufficient and / or the crack length is too high in the case of Comparative Examples A5, A6, A12, A13, A17, A22, A23, A27, A28. Note that in the case of the counterexample, the relationship -0.5x(Cr+Fe)+25%≤Mo+W≤-0.5x(Cr+Fe)+30% is not satisfied.

[0290] Furthermore, as shown in Comparative Examples A6, A13, A17, A23 and A28, alloys having an iron content greater than 1.0% exhibit reduced ductility and increased hot cracking sensitivity.

[0291] In general, the inventors have found that a surface fraction FS of the precipitated phase greater than 1.5% results in a flow rate of less than 100 J / cm 2 KCV resilience and / or crack length greater than 20 mm.

[0292] The inventors also conducted a second series of tests under the same conditions as described for the first series of tests, but using strips made of alloys having the compositions summarized in Table 3. In addition, the results of the tests conducted on the strips are shown in Table 4.

[0293]

[0294]

[0295] Table 3: Composition of alloys tested in the second series

[0296] In the alloy of Table 3, the Al content is between 0.01% and 0.35%, the N content is between 0.001% and 0.05%, the Mg and Ca contents are less than or equal to 0.005%, and the P content is less than or equal to 0.005%. In addition, the alloy does not contain niobium.

[0297] For all alloys in Table 3, the remainder is nickel, plus impurities resulting from manufacturing.

[0298] In addition, all compositions are expressed in weight percent.

[0299]

[0300]

[0301] Table 4: Results of tests carried out on strips produced from the alloys of Table 3

[0302] Furthermore, during the potentiometric testing, alloys B1-B28 of Table 3 produced pitting potentials V greater than or equal to 150 mV relative to the reference potential of a saturated calomel electrode. Alloy 625 has better resistance to localized corrosion.

[0303] It was thus found that in the cases of Examples B2 to B4, B8 to B11, B14 to B16, B19 to B21, B25 and B26 corresponding to alloys having the compositions described above, desired properties in terms of yield strength, resilience, weldability, surface fraction of precipitated phases and localized corrosion resistance were obtained.

[0304] Other results confirm the conclusions drawn from Table 2.

[0305] In particular, in the case of Comparative Examples B1, B7, B18, and B24, the yield strength Rp 0.2 Less than or equal to 500 MPa, while in the case of comparative examples B5, B6, B12, B13, B17, B22, B23, B27, and B28, the KCV rebound resilience is insufficient. Note that in the case of the counterexample, the relationship -0.5x(Cr+Fe)+25%≤Mo+W≤-0.5x(Cr+Fe)+30% is not satisfied.

[0306] Furthermore, if the alloy contains iron in an amount greater than 1.0%, weldability and elasticity may be reduced.

[0307] Furthermore, by comparing the results of Table 2 and Table 4, it can be seen that the addition of rare earth thus improves the hot cracking resistance of the alloy.

[0308] The addition of rare earths is particularly advantageous when the base metal to be welded has a higher sulfur and / or oxygen content than the filler wire. In fact, the inventors have found that rare earths contribute to deoxidation and / or desulfurization of the weld pool during the welding operation and thus contribute to improving hot cracking resistance.

[0309] The alloy according to the invention has a yield strength Rp greater than or equal to 500 MPa. 0.2 and greater than or equal to 100 J / cm 2 The KCV rebound resilience can be used to obtain the relative yield strength Rp 0.2 Below 500 MPa, the mechanical properties of the base metals (such as alloys X56, X60, X65 and X70) are overmatched. Therefore, for the design of welded assemblies made of such alloys as base material, the properties of the weld can be neglected.

[0310] In addition, the alloy exhibits:

[0311] Greater than or equal to comparison Corrosion resistance of 625 alloy;

[0312] Solderability greater than or equal to comparison Weldability of 625 alloy.

[0313] Considering its properties, the alloy according to the invention is therefore particularly suitable for use as a filling material for manufacturing pipeline pipes intended to transport oil or gas and suitable for laying in deep sea waters, in particular down to a depth of about 3,000 m, at high production rates (in particular about 2 km / day).

[0314] In view of its good properties, the alloy according to the invention can also be advantageously used in the context of components such as those described above.

Claims

1. An alloy having the following composition by weight: 16.5% ≤ Cr ≤ 25.0% 11.0% ≤ Mo ≤ 18.0% 2.0% ≤ W ≤ 7.0% Fe ≤ 1.0% Mo+W ≤ - 0.5 x (Cr+Fe) + 30% Mo+W ≥ - 0.5 x (Cr+Fe) + 25% Ti+Ta ≤ 0.80% 0.01% ≤ Si ≤ 0.75% 0.01% ≤ Al ≤ 0.35% 0.01% ≤ Mn ≤ 0.35% Ca ≤ 0.005% Mg ≤ 0.005% Nb ≤ 0.01% 0.001% ≤ C ≤ 0.05% 0.001% ≤ N ≤ 0.05% S ≤ 0.003% P ≤ 0.005% The remainder is nickel and unavoidable impurities resulting from manufacturing, with a nickel content greater than or equal to 54%.

2. The alloy according to claim 1, wherein The iron content is less than or equal to 0.5%.

3. The alloy according to claim 1 or 2, wherein The alloy further has rare earth, wherein 0.0010%≤rare earth≤0.015%, and silicon content is less than or equal to 0.25%.

4. The alloy according to claim 3, wherein The rare earth is selected from yttrium, cerium, lanthanum or a mixture thereof.

5. The alloy according to claim 4, wherein The rare earth is selected from yttrium, or a mixture of cerium and lanthanum.

6. A coated component (26) comprising a substrate (28) made of a base material which is a metallic material and a coating (30) made of the alloy according to claim 1 or claim 2.

7. The coated component according to claim 6, wherein: The coating component (26) is a pipe section (7).

8. A filler welding wire made of an alloy having the composition of claim 1 or claim 2.

9. A method for manufacturing the filler wire of claim 8, the method comprising the following steps: Providing a semi-finished product made of the alloy according to claim 1 or claim 2; Thermal transformation of the semi-finished product to form an intermediate welding wire; and The intermediate welding wire is transformed into a filler welding wire having a diameter smaller than a diameter of the intermediate welding wire, the transformation comprising a drawing step.

10. A welded assembly (1; 7; 20), comprising at least two parts of a component (3; 12; 7), each part being made of a base material, the parts of the component (3; 12; 7) being joined together by a weld (5; 15; 22), the weld being obtained by a filler wire according to claim 8, wherein the base material is selected from the group consisting of an iron-nickel alloy, a nickel-based alloy and a carbon steel.

11. The welding assembly according to claim 10, wherein: The nickel-based alloy is selected from C-276, C-4 or C-22.

12. Welded assembly according to claim 10, forming a pipe section (7), comprising a metal sheet bent into a pipe shape, the longitudinal edges (12) of the metal sheet forming part of components (3) connected to each other by weld seams (15).

13. The welding assembly according to claim 12, wherein: The pipe section (7) is provided with a coating (30) made of the alloy according to claim 1 or claim 2 on at least a portion thereof.

14. A welded assembly according to claim 10, forming a pipe (20) comprising at least two pipe segments (7), the pipe segments (7) forming part of a component (3), and the weld seam (22) extending along the circumference of the pipe (20).

15. A method for producing a welded assembly (1; 7; 20) as claimed in claim 10, comprising welding together the two parts of the component (3; 12; 7) by means of a filler wire as claimed in claim 8.

16. A method for manufacturing a welded assembly (7) as claimed in claim 12, wherein: The welding step is a step of welding the longitudinal edges (12) of the metal plates (9) together.

17. A method for producing a welded assembly (20) as claimed in claim 14, comprising the following consecutive steps before the welding step: supplying a first pipe section (7) and a second pipe section (7), wherein the first pipe section (7) and the second pipe section (7) each extend along a longitudinal axis (M) and are made of the base material; Positioning the first pipe segment and the second pipe segment (7) such that the longitudinal end (24) of the first pipe segment (7) is arranged to face the longitudinal end (24) of the second pipe segment (7) along the longitudinal axis (M) of the first pipe segment and the second pipe segment (7); and in, The welding step is a step of welding together the two longitudinal ends (24) facing the first pipe section and the second pipe section (7).

18. A component or part of a component made from the alloy of claim 1 or claim 2, the component or part of a component being obtained by metal additive manufacturing.

19. A method for manufacturing a component or a part of a component, comprising the step of manufacturing the component or the part of the component by a metal additive manufacturing process, wherein the metal additive manufacturing process uses a filler wire made of the alloy according to claim 1 or claim 2 and / or a powder made of the alloy according to claim 1 or claim 2 as a filler material.

20. Use of a filler welding wire, wherein the filler welding wire is the filler welding wire according to claim 8: Used as a welding filler wire for welding together two parts of a component made of a base material, the base material being an iron-nickel alloy, a nickel-based alloy or carbon steel; and / or Used as a hardfacing welding wire for producing a coating on a component or part of a component made of a base material, the base material being a metallic material; and / or For use as filler wire in metal additive manufacturing processes.

21. The use of a filler wire according to claim 20, wherein: The nickel-based alloy is selected from C-276, C-4 or C-22.

22. A metal powder made from the alloy according to claim 1 or claim 2.

23. A method of manufacturing the metal powder of claim 22, the method comprising the steps of providing the filler wire of claim 8, and plasma atomizing the filler wire to obtain the metal powder.

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