Nickel-based alloys for manufacturing pipeline tubing

Abstract

The present invention has the following composition by mass: 16.5%≦Cr≦25.0%; 11.0%≦Mo≦18.0%; 2.0%≦W≦7.0%; Fe≦1.0%; Mo+W≦-0.5×(Cr+Fe)+30%; Mo+W≧-0.5×(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≦0.0 1%; 0.001%≦C≦0.05%; 0.001%≦N≦0.05%; S≦0.003%; P≦0.005%; optionally 0.0010%≦Rare Earths≦0.015%, wherein the silicon content is less than or equal to 0.25% in the presence of rare earths in amounts between 0.0010% and 0.015%, the remainder being nickel and unavoidable impurities resulting from processing, and the nickel content is greater than or equal to 54%.

Description

[Technical Field]

[0001] The present invention relates to nickel alloys intended to be used in particular in the petrochemical and petroleum product extraction fields, more particularly as part of the manufacture of pipeline tubing for transporting gas or oil. [Background technology]

[0002] Gas and oil development requires the construction of offshore pipelines. For productivity and economic profitability purposes, it is desirable to lay pipelines at a laying rate of approximately 2 km / day. Currently, there are three technologies that meet such productivity requirements: S-lay technique: Pipe sections, typically 9 or 12 m long, are manufactured onshore in units called spool bases, then transported at sea by ship and butt-welded horizontally on a barge. The laying is called S-lay, recalling the shape the tube takes before contacting the seabed. S-lay technique is suitable for seabeds less than 2,000 m deep. J-lay technology: The J-lay technology is more recent and is adapted to deep waters (2,000m to 4,000m). The pipe sections are welded together (at a slight angle) on a vertical barge at sea, forming a J-shape before contacting the seabed. R-lay technology: The most recent R-lay technology is dedicated to small diameter tubing and non-deepwater areas. The tubing lines are welded together on land, then wound around a wheel for transport at sea, and then unwound from the wheel using a special barge. R-lay technology is the most efficient.

[0003] Such installation techniques subject the tubes, and in particular the orbital welds between the tube sections, to mechanical stresses, particularly under the influence of bending of the tube during installation and under the influence of the weight of the tube before contacting the seabed, and therefore the tubes, and in particular the welds, must be designed to withstand such stresses in order to avoid deformation of the tube during the installation phase.

[0004] In addition to the requirements regarding laying speed, there is also a need to increase the laying depth in order to keep the buried material usable. The laying depth can reach depths of about 2,500 to 3,000 m. Such an increase in laying depth increases the mechanical stress on the tubes and therefore requires the use of carbon steels with increasingly higher mechanical properties.

[0005] The tube sections used are typically manufactured in factories by rolling steel plate and then welding the edges longitudinally with a steel filler wire using a MIG / MAG process, the composition of which is selected according to the grade of steel. The tube section wall thickness is typically around 25 mm, and its diameter ranges from 25 cm to 130 cm.

[0006] Alternatively, and depending on the application, the tube sections are manufactured by billet extrusion, as well as the tube obtained by orbital welding of the tube sections, in such cases without any longitudinal welds (seamless tube).

[0007] The mechanical strength of pipe sections specified according to the steel grade is reproduced below according to API Specification 5L for steel grades X56, X60, X65, X70, or X80 that can be used to manufacture the pipe sections. The steel grade corresponds to the yield strength of the steel plate in ksi.

[0008] [Table 1]

[0009] Steel grades X56, X60, X65, X70, or X80 are defined in the American Petroleum Institute's "API Specification 5L" document, 45th Edition, December 2012.

[0010] If the tube section contains longitudinal welds, it is desired during the manufacture of the tube section to obtain welds with mechanical properties equal to or greater than those of the base plate steel (overmatch) so that the pipe section can be designed without taking the welds into account, depending on the laying conditions (S, J, R) and only on the type of operation of the line, for example to determine the thickness of the pipe section and the grade of steel used.

[0011] If tube sections are produced without longitudinal welds ("seamless" technology), for example by billet extrusion, it is possible to omit the specifications required for longitudinal welds ("overmatch").

[0012] After the tube sections are manufactured, the inner surface of the tube section, including any longitudinal welds, is coated with a coating layer by welding with a filler wire. The purpose of this coating operation is to ensure corrosion resistance of the tube during the transportation of more or less corrosive petroleum products. The internal coating is typically made of Inconel® 625 alloy, which has the following composition by mass: Cr: 20.0~23.0% Fe≦5.0% Mo: 8.0~10.0% Nb+Ta: 3.15~4.15% C≦0.10% Mn≦0.50% Si≦0.50% P≦0.002% S≦0.015% Al≦0.40% Ti≦0.40% Other elements ≤ 0.5% The remainder is nickel and unavoidable impurities arising from production, with Ni≧58%.

[0013] Inconel® 625 alloy is defined in Table 1 of specification 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-3 (number UNS N06625).

[0014] Once the tube sections are manufactured, they are transported on barges and butt-welded by orbital welding as the tubes are laid using one of the techniques previously mentioned.

[0015] Whatever the laying technique used, the butt welds (orbital) made between the tube sections should withstand the bending stresses of the line during laying and the line's own weight before contacting the seabed. The mechanical strength of the orbital weld is therefore very important to prevent weld distortion during the laying stage.

[0016] Generally, the following properties are required for orbital welds between pipe sections: - Overmatch: seeks to obtain an orbital weld with a mechanical strength greater than or equal to that of the base metal, i.e. the steel of the pipe section. As mentioned above for longitudinal welds of pipe sections, overmatch is used to design pipes according to the laying conditions (S, J, R) and according to the type of operation of the line without taking the weld into account, and in particular to determine the thickness of the pipe and the grade of steel used. - A localized corrosion resistance on the inside that is greater than or equal to the corrosion resistance of the coating of the pipe section, in order to be able to design the pipe to the requirements regarding localized corrosion resistance without taking into account the presence of orbital welds.

[0017] Throughout the description, localized corrosion refers to corrosion that is likely to result in a pitting corrosion mechanism.

[0018] To meet all of the above requirements, the inventors propose using an Inconel® 625 alloy filler wire to create an orbital weld, where the root pass is made in the coating, and using a steel of a grade equivalent to the base metal to finish the weld with the filler pass. Such a welding technique ensures a certain continuity of the materials used, thus providing good mechanical properties. On the other hand, such welding entails significant problems of hot cracking, and therefore weldability, related to the dilution of the Inconel® 625 alloy. Therefore, such a solution is not entirely satisfactory. In particular, cracks that appear during welding must be repaired, resulting in significant additional costs. Furthermore, if the cracks are not repaired, they risk causing the tube to break during operation.

[0019] The inventors have also proposed to perform a full weld using a single wire made of Inconel® 625 alloy. Such a welding solution is indeed economical. Furthermore, the weld does not cause any problems with hot cracking and provides resistance to corrosion comparable to that of coatings. Furthermore, the weld is widely used to weld tubes up to grade X56 or even X60. However, it is no longer suitable for higher steel grades (X65, X70, and X80). However, the aforementioned requirements, more particularly with regard to the speed and depth of laying, increasingly necessitate the use of steels of grades higher than X60, in particular grade X65 or even grade X70. [Prior art documents] [Non-patent literature]

[0020] [Non-Patent Document 1] The American Petroleum Institute, "API Specification 5L" document, 45th edition, December 2012 [Non-patent document 2] 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-3 (number UNS N06625) [Non-patent document 3] Standard NF EN ISO 148-1 (January 2011) [Non-patent document 4] European Standard FD CEN ISO / TR 17641-3 (November 2005) [Non-Patent Document 5] American Petroleum Institute, API Specification 5L Document, 45th Edition, December 2012 [Non-patent document 6] 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-4 (number UNS N10276) [Non-Patent Document 7] 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) [Non-patent document 8] 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-10 (number UNS N06022) [Non-Patent Document 9] ASTM B214-07 standard [Non-Patent Document 10] Standard NF EN ISO 6892-1 (December 2019) Summary of the Invention [Problem to be solved by the invention]

[0021] It is therefore an object of the present invention to overcome the above-mentioned drawbacks and to provide an alloy that can be used as a filler material for manufacturing pipeline tubes intended to transport oil or gas and suitable for laying in deep waters, offshore, in particular below a depth of about 3,000 m, at high production rates, in particular of the order of 2 km / day.

[0022] The laying of tubes at depths below about 3,000 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, a minimum of: a yield strength Rp greater than or equal to 500 MPa 0.2 and 100J / cm 2 and advantageously a yield strength RP greater than or equal to 550 MPa. 0.2 and / or 120 J / cm 2 It is desired to obtain a KCV elasticity greater than or equal to

[0023] Furthermore, the use of the tubing as a pipeline for the transportation of oil or gas requires good corrosion resistance of the filler material as well as good weldability. More specifically, localized corrosion resistance and weldability are required to be greater than or equal to that of Inconel® 625 alloy. [Means for solving the problem]

[0024] To this end, the present invention provides a composition comprising the following by weight: 16.5%≦Cr≦25.0% 11.0%≦Mo≦18.0% 2.0%≦W≦7.0% Fe≦1.0% Mo+W≦-0.5×(Cr+Fe)+30% Mo+W≧-0.5×(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% If necessary, 0.0010%≦Rare Earth≦0.015% wherein the silicon content is less than or equal to 0.25% in the presence of rare earths with a content comprised between 0.0010% and 0.015%; It relates to alloys having a nickel content greater than or equal to 54%, the remainder being nickel and unavoidable impurities resulting from production.

[0025] The alloy according to the invention may comprise one or more of the following characteristics, taken individually or according to any technically possible combination: - iron content less than or equal to 0.5%; the rare earths are selected from yttrium, cerium, and lanthanum, and mixtures thereof; and the rare earth is selected from yttrium or a mixture of cerium and lanthanum;

[0026] The invention further relates to a coated part comprising a substrate made of a base material and a coating made of an alloy according to any of claims 1 to 4, wherein the base material is a metallic material, preferably a carbon steel, for example X56, X60, X65 or X70 steel.

[0027] According to a particular embodiment, the coated part is a tube section.

[0028] The present invention further relates to a filler wire made from the above alloy.

[0029] The present invention provides a method for manufacturing the filler wire described above, comprising the following steps: - providing a semi-finished product made from the alloy; - high temperature converting the semi-finished product to form an intermediate wire; - a process including a drawing step to convert the intermediate wire into a filler wire having a smaller diameter than the intermediate wire; The present invention relates to a method, including:

[0030] The present invention further provides a welded assembly comprising at least two parts of a component, each of which is made of a base material, the parts of which are welded together using a weld obtained from the filler wire described above. Bead and the base material is selected from iron-nickel alloys such as Fe-9Ni, nickel alloys such as C-276, C-4 or 22, and carbon steel, for example X56, X60, X65 or X70 steel.

[0031] The welded assembly according to the invention may further comprise one or more of the following characteristics, taken individually or according to any technically possible combination: - A welded assembly forms a tube section that includes sheet metal bent into the shape of a tube, the longitudinal edges of which are welded Bead forming part of the parts joined together by the tube section is provided with a coating made of the above-mentioned alloy on at least a portion, preferably all, of its internal surface; and - a welded assembly forms a tube comprising at least two tube sections, the tube sections forming part of a part, and the welded Bead extends around the circumference of the tube, the tube section being preferably a tube section as described above.

[0032] The invention further relates to a method for producing a welded assembly, which method comprises the step of welding together, in particular by arc welding, two parts of a component using the filler wire described above.

[0033] The manufacturing method by assembly may further comprise one or more of the following characteristics, taken individually or according to any technically conceivable combination: - the welding step is a step of welding the longitudinal edges of the sheet metal together, the welding being preferably a longitudinal butt weld; and - the method comprising, before the welding step, the following successive steps: - providing a first tube section and a second tube section, each extending along a longitudinal axis and made of a base material; - positioning the first and second tube sections such that a longitudinal end of the first tube section faces a longitudinal end of the second tube section along a longitudinal axis of the first and second tube sections; Including, The welding step is welding the two longitudinal facing ends of the first and second tube sections together, preferably by orbital butt welding.

[0034] The present invention further relates to a component or portion of a component made from the alloy described above, wherein the component or portion of a component has been produced by additive manufacturing.

[0035] The additive manufacturing process more particularly uses, as filler material, a filler wire made of the above-mentioned alloy and / or a powder made of the above-mentioned alloy.

[0036] Additive manufacturing processes are additive manufacturing processes that use, for example, an electric arc, a laser beam, and / or an electron beam as an energy source to melt a filler material.

[0037] For example, the additive manufacturing process may be 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.

[0038] The present invention further relates to a method for manufacturing a component or portion of a component, comprising manufacturing said component or said portion of a component by a metal additive manufacturing process using, as filler material, a filler wire made of the above-mentioned alloy and / or a powder made of the above-mentioned alloy.

[0039] Additive manufacturing processes are additive manufacturing processes that use, for example, an electric arc, a laser beam, and / or an electron beam as an energy source to melt a filler material.

[0040] For example, the additive manufacturing process is a wire-arc, wire-laser, electron beam-wire process, or a hybrid additive manufacturing process that combines wire-arc and laser-powder or wire-arc and wire-laser technologies.

[0041] The present invention further provides the use of the filler wire described above, as a welding filler wire for welding together two parts of a part made of a base material, which is an iron-nickel alloy such as Fe-9Ni, a nickel alloy such as C-276, C-4 or 22, or a carbon steel, in particular X56, X60, X65 or X70 steel; and / or as hardfacing wires for producing coatings on components or parts of components, made of a metal-based material, preferably carbon steel, for example X56, X60, X65 or X70 steel; and / or - As a filler wire in metal additive manufacturing processes, Regarding use.

[0042] The present invention further relates to metal powders made of the above alloys.

[0043] The present invention further relates to a method for producing metal powders made of the above-mentioned alloys.

[0044] The invention will be better understood on reading the following description, given purely by way of example, and by referring to the enclosed drawings, in which: [Brief explanation of the drawings]

[0045] [Figure 1] 1 is a schematic cross-sectional view of a welded assembly according to the present invention; [Figure 2] 1 is a schematic perspective view of a tube section according to the present invention; [Figure 3] 1 is a schematic top view of a sheet metal used in carrying out a process for manufacturing a tube section. FIG. [Figure 4] 1 is a schematic perspective view of a tube according to the present invention; [Figure 5] 1 is a schematic perspective view of a part coated according to the present invention; [Figure 6] FIG. 1 is a schematic perspective view of a part produced by additive manufacturing according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0046] In the following description, all contents are expressed as percentages by weight.

[0047] The alloy according to the invention has the following composition by mass: 16.5%≦Cr≦25.0% 11.0%≦Mo≦18.0% 2.0%≦W≦7.0% Fe≦1.0% Mo+W≦-0.5×(Cr+Fe)+30% Mo+W≧-0.5×(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% 0.0010%≦Rare earth≦0.015% as needed wherein the silicon content is less than or equal to 0.25% in the presence of rare earths in a content comprised between 0.0010% and 0.015%; The remainder is nickel or unavoidable impurities resulting from production, the nickel content of which is greater than or equal to 54%.

[0048] Unavoidable impurities resulting from manufacturing refer to elements present in the raw materials used to make the alloy or coming from the equipment used to make the alloy, e.g., furnace refractories. Such residual elements have no metallurgical effect on the alloy.

[0049] A nickel content of greater than or equal to 54% by weight in the alloy provides good ductility of the base metal and good resistance to stress corrosion.

[0050] At contents comprised between 16.5% and 25.0%, by weight, chromium provides good resistance to generalized corrosion and improves the mechanical properties of the alloy. More particularly, the inventors have found that when the chromium content is less than 16.5%, by weight, the resistance to generalized corrosion is insufficient. Furthermore, chromium contents higher than 25.0%, by weight, result in the precipitation of σ-phase, which is associated with a loss of ductility and an increased susceptibility to hot cracking, and therefore, deteriorates the mechanical properties of the alloy.

[0051] Preferably, the chromium content is greater than or equal to 17.0% and less than or equal to 23.0%.

[0052] When present in a content comprised between 11.0% and 18.0% by weight, molybdenum improves the resistance to localized corrosion.

[0053] Furthermore, molybdenum significantly improves the mechanical properties: the inventors have found that for molybdenum contents of less than 11.0% by weight, localized corrosion resistance and mechanical properties are insufficient, whereas molybdenum contents higher than 18% result in the precipitation of undesirable phases, resulting in a loss of ductility and an increased susceptibility to hot cracking.

[0054] Preferably, the molybdenum content is greater than or equal to 11.5% and less than or equal to 16.5%.

[0055] The tungsten content is between 2.0% and 7.0% by mass. When present at such a content, tungsten also improves resistance to localized corrosion. Furthermore, tungsten improves mechanical properties. The inventors have found that a tungsten content of less than 2.0% results in insufficient resistance to localized corrosion. Furthermore, a tungsten content greater than 7.0% results in the precipitation of undesirable phases, resulting in loss of ductility and increased susceptibility to hot cracking.

[0056] The iron content is less than or equal to 1.0% by weight. The addition of iron degrades resistance to generalized corrosion. An iron content of less than or equal to 1.0% by weight allows the alloy to be produced from scrap material containing residual iron, thereby reducing production costs. At contents higher than 1.0% by weight, iron also enhances the precipitation of undesirable phases, resulting in a loss of ductility and an increased susceptibility to hot cracking.

[0057] Preferably, the iron content is less than or equal to 0.5% by weight.

[0058] The total titanium and tantalum content is less than or equal to 0.80% by weight. While titanium and tantalum present at the claimed levels significantly improve mechanical properties, their low solubility in Ni-Cr alloys causes precipitation of undesirable phases. Therefore, the contents of these elements must be limited to low levels. However, these elements contribute to deoxidation of the alloy during manufacturing. The inventors have found that when Ti + Ta is greater than 0.80% by weight, precipitation of undesirable phases is observed, resulting in loss of ductility and increased susceptibility to hot cracking.

[0059] According to the present invention, Mo+W≦−0.5×(Cr+Fe)+30 mass %. The inventors have found that by satisfying the above relationship, the fracture energy KCV≧100 J / cm 2 It has been observed that this leads to obtaining satisfactory ductility, as represented by a total crack length of less than or equal to 20 mm, and good weldability, as represented by a total crack length of less than or equal to 20 mm.

[0060] Fracture energy KCV is J / cm 2 The fracture energy KCV reflects the elasticity of the part and is determined, for example, by elasticity tests carried out at room temperature according to standard NF EN ISO 148-1 (January 2011).

[0061] The crack length is determined in particular by the Varestraint test according to European Standard FD CEN ISO / TR 17641-3 (November 2005) under a plastic deformation of 3.2%.

[0062] Furthermore, Mo+W≧−0.5×(Cr+Fe)+25% by mass. The inventors have found that satisfying the above relationship provides a satisfactory mechanical strength, in particular a yield strength Rp greater than or equal to 500 MPa. 0.2 We found that this leads to obtaining the following.

[0063] At the aforementioned levels, silicon and aluminum enhance deoxidation and manganese enhances desulfurization during alloy production.

[0064] The calcium and magnesium contents in the alloy are limited to 0.005% by weight each so as not to degrade weldability, more particularly so as not to degrade weld seam quality, particularly the formation of slag at the surface which can lead to instabilities in the arc and in the liquid bath.

[0065] 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 deteriorate the resistance to hot cracking. In particular, niobium segregates strongly within the interdendritic spaces, enhancing the precipitation of undesirable phases.

[0066] The alloy further contains carbon and nitrogen in a content comprised between 0.001 and 0.05% by weight. Carbon is controlled to facilitate deoxidation during alloy production. Carbon and nitrogen also ensure microstructural refinement by precipitation of Ti-(C,N) carbonitrides in conjunction with the addition of titanium.

[0067] To improve the resistance to hot cracking, the S and P contents are limited as much as possible, said contents being less than or equal to 0.003% and 0.005% by weight, respectively, in the above alloy.

[0068] Optionally, the alloy contains rare earths in a content comprised between 0.0010 and 0.015% by weight. Rare earths scavenge sulfur and residual oxygen. Rare earths improve resistance to hot cracking when welding base metals containing higher residual S+O contents than the filler wire. However, at contents greater than 0.015%, precipitation of eutectic phases at low melting points is enhanced, especially in the presence of silicon, resulting in loss of ductility and increased susceptibility to hot cracking.

[0069] The rare earths are preferably selected from yttrium, cerium and lanthanum, or from mixtures of said elements.

[0070] According to one embodiment, the rare earth comprises yttrium, in such case the alloy comprises between 0.0010 and 0.015% by weight of yttrium.

[0071] According to one variant, the rare earth consists of a mixture of cerium and lanthanum, in such a case the content of Ce+La in the alloy is comprised between 0.0010 and 0.015% by weight.

[0072] In the presence of rare earths in a content comprised between 0.0010 and 0.015% by weight, the silicon content is limited to 0.25% by weight, preferably 0.20% by weight. In such cases, the silicon content is therefore comprised between 0.01 and 0.25% by weight, preferably between 0.01 and 0.20% by weight. In fact, silicon enhances the formation of phases containing rare earths, thereby reducing the possibility that the rare earths will capture residual sulfur and oxygen.

[0073] The alloy according to the invention has a yield strength Rp comprised between 500 MPa and 600 MPa. 0.2 and 100 J / cm 2 It can be used to obtain malleable, ductile welds that have a KCV modulus greater than or equal to 1000 kJ / cm2 and exhibit an overmatch of mechanical properties compared to base materials made from X56, X60, X65, or X70 steel.

[0074] As mentioned above, steel grades X56, X60, X65, X70, and X80 are defined in the American Petroleum Institute's API Specification 5L document, 45th Edition, December 2012.

[0075] Furthermore, the alloy according to the present invention - good resistance to corrosion, in particular to localized corrosion, greater than or equal to the resistance of the comparative Inconel® 625 alloy; - Weldability greater than or equal to the weldability of the comparative Inconel® 625 alloy It has.

[0076] Thereby, longitudinal and / or orbital welds are characterized by a yield strength Rp greater than or equal to 500 MPa. 0.2 and 100 J / cm 2 It can be neglected for the design of welded joints designed to have a KCV modulus greater than or equal to 100 kJ / s, and especially those including X56, X60, X65, and X70 steels as base materials.

[0077] Taking into account its properties, the alloy according to the invention is therefore particularly suitable for use as a filler material for manufacturing pipeline tubes intended for the transportation of oil or gas and suitable for laying in deep waters on the high seas, in particular at depths below about 3,000 m, at high production rates, in particular of the order of 2 km / day.

[0078] Such alloys can therefore be advantageously used as filler metal for longitudinal and / or orbital welding of pipeline tubes made of X56, X60, X65, or X70 steel and intended to be laid at considerable depths, e.g., less than 3,000 m, and at high laying speeds.

[0079] Due to the good properties of resistance to corrosion obtained, the alloy can also be used to produce an internal coating intended to improve the resistance to corrosion of such tubes.

[0080] The alloy according to the invention can be obtained by any suitable method known to those skilled in the art.

[0081] For example, in the first step, the starting material is fed into an electric arc furnace. The starting material is selected to obtain an alloy containing less than 1.0% by weight of iron. This is particularly a new material. The starting material is then melted in the electric arc furnace and then subjected to vacuum oxygen decarburization (VOD) in the usual way. - decarburization by oxygen injection and vacuum pumping (at a few mbar), - Deoxidation and desulfurization under lime slag, and - Adjustment of reducing elements such as Ti and Al This is carried out to obtain the following.

[0082] The present invention further relates to a filler wire made of an alloy having the above-mentioned composition.

[0083] Such a filler wire is particularly suitable for use in a filler wire TIG or plasma welding process or a MIG / MAG welding process.

[0084] For example, filler wire is - a welding filler wire for welding together two parts of a component, made of a base material, the base material being in particular an iron-nickel alloy such as Fe-9Ni, i.e. containing nickel in a content constituting between 5% and 10% by weight, or a nickel alloy such as C-276, C-4 or 22, or a carbon steel, in particular X56, X60, X65 or X70 steel; and / or - as a hardfacing wire made of a base material, in particular for producing a coating on a component or part of a component, the base material being carbon steel, in particular X56, X60, X65 or X70 steel It is intended to be used.

[0085] Alloy C-276 is specified 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 AWS classification reference ERNiCrMo-4 (number UNS N10276).

[0086] Alloy C-4 is specified 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).

[0087] Alloy 22 is specified 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 AWS classification reference ERNiCrMo-10 (number UNS N06022).

[0088] The components or parts of components are in particular tube sections, tubes and / or metal sheets or parts of metal sheets made of the base material.

[0089] For example, the filler wire is also intended to be used as a filler wire in a metal additive manufacturing process.

[0090] Additive manufacturing processes are those that use, for example, an electric arc, a laser beam, and / or an electron beam as an energy source to melt the filler wire.

[0091] The additive manufacturing process is in particular a directed energy deposition additive manufacturing process, during which a filler material is deposited, in particular through a nozzle, and is instantly melted by focused thermal energy, in particular by a laser beam, an electron beam, and / or an electric arc.

[0092] By way of example, the additive manufacturing process is a wire-arc (WAAM or "wire-arc additive manufacturing"), wire-laser, electron beam-wire ("electron beam freeform fabrication" or "electron beam additive manufacturing") process, or a hybrid additive manufacturing process combining wire-arc and laser-powder techniques or wire-arc and wire-laser techniques.

[0093] In the case of hybrid wire-arc and laser-powder processes, the powder used has the same composition as the wire.

[0094] Powders whose particle size distribution after screening is between 20 μm and 150 μm are obtained, for example, from filler wire according to the invention using plasma spraying techniques. Preferably, the filler wire used to produce the powder has a diameter of about 3 mm.

[0095] The particle size distribution of the powder is determined, inter alia, by the following measurement method: The powder batch is separated into multiple powder size distributions using an ultrasonically vibrated stainless steel screen. The analysis of the size distribution of the powders obtained from the screening is carried out according to the ASTM B214-07 standard. The screening is used to obtain five size classes: <20 μm - 20 μm to 45 μm - 45 μm to 75 μm - 75 μm to 105 μm - >105 μm.

[0096] The plasma spraying technique for producing powder from wires is known per se and therefore will not be described in more detail.

[0097] The components or parts of components are particularly intended for the aeronautical, transport or energy markets. The components or parts of components form, for example, a case, a frame, a tube with a complex shape, a valve, a mounting lug or a part of a component having a specific function. By way of example, a part of such a component forms a heat exchange element comprising channels for the circulation of a fluid, formed, for example, by additive manufacturing on a support part, which support part is, for example, made of a material different from that of the heat exchange element.

[0098] The present invention further relates to a method for producing a filler wire made of the above-mentioned alloy.

[0099] The method comprises, in a first step, the provision of a semi-finished product made of said alloy. For this purpose, the alloy is cast in ingots or directly into billets, in particular by means of continuous casting, in particular rotary casting. The semi-finished product obtained at the end of such a step is therefore advantageously an ingot or a billet, having a diameter, for example comprised between 130 and 230 mm, more particularly equal to about 150 mm.

[0100] The semi-finished product is then converted by high temperature conversion to form an intermediate wire.

[0101] In particular, during the high-temperature conversion process, the semi-finished product, ie in particular an ingot or a billet, is heated to a temperature comprised between 1180° C. and 1220° C., in particular in a gas furnace.

[0102] They are then subjected to high-temperature roughening to reduce the cross section of the semi-finished product, for example by giving it a square cross section with sides of about 100 to 200 mm. A semi-finished product with reduced cross section is thereby obtained. The length of the semi-finished product with reduced cross section is in particular comprised between 10 and 20 meters.

[0103] The semi-finished product with reduced cross section is then again subjected to high-temperature transformation at a temperature comprised between 1050 and 1150°C to obtain intermediate wire. The intermediate wire is in particular machine wire. The wire has a substantially equal diameter, for example comprised between 5 mm and 21 mm, in particular 5.5 mm. Advantageously, during such a process, the intermediate wire is produced by hot rolling in a wire mill train.

[0104] If necessary, the intermediate wire is then subjected to a hyperquenching treatment in a pool, after a heat treatment in a gas furnace at a temperature comprised between 1150°C and 1220°C for a period comprised between 60 and 120 minutes.

[0105] The intermediate wire is then washed with acid and then wound into a coil.

[0106] If necessary, the intermediate wire thus obtained is drawn using a wire drawing installation of known type to obtain a filler wire, which has a diameter smaller than that of the starting wire, in particular between 0.5 mm and 3.5 mm, and advantageously between 0.8 mm and 2.4 mm.

[0107] The wire drawing process comprises one or more wire drawing passes, depending on the final diameter to be reached, with an annealing preferably being carried out between two successive wire drawing passes, for example during a pass under a reducing atmosphere at a temperature of around 1150°C.

[0108] The wire drawing step is preferably followed by cleaning the surface of the drawn wire and then winding the wire.

[0109] The wire drawing pass is a cold pass.

[0110] Any other method of producing alloys according to the present invention and of producing finished articles made from alloys known to those skilled in the art can be used for this purpose.

[0111] The present invention further provides a welding process obtained from the above filler wire. Bead It concerns a welded assembly 1 comprising at least two parts 3 made of base metal joined together by 5. The above mentioned welded assembly is shown diagrammatically in FIG.

[0112] The dilution of the wire during welding is for example comprised between 1% and 10%, in particular approximately equal to 5%.

[0113] Throughout the text, "parts of a part" welded together refers both to the case where the parts welded together belong to two originally separate parts, and to the case where the parts are two parts of the same part folded onto themselves, for example, two longitudinal edges of a piece of sheet metal welded to form a tube.

[0114] 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, i.e. with a nickel content constituting between 5 and 10% by weight, or a nickel alloy such as C-276, C-4 or 22.

[0115] The invention further relates to a welding method for welding together at least two parts of a component 3 made of the base metal defined above, so as to produce a welded assembly 5 as illustrated in FIG.

[0116] In a first step, the filler wire described above is provided, as are the portions of the component 12 made of base metal that will be welded together by the welding process.

[0117] The portions of the component 12 are then welded together using filler wire as the welding filler. During such a process, a butt weld is preferably performed.

[0118] A welding process can include one or more welding passes. Conventionally, a welding process includes a first welding pass, called a root pass, followed by one or more additional welding passes, called filler passes. All welding passes are performed using the filler wire according to the present invention described above. Therefore, dilution of the filler wire is limited to dilution with the molten base metal obtained from the weld.

[0119] The dilution of the wire during welding is for example comprised between 1% and 10%, in particular approximately equal to 5%.

[0120] The welding is carried out, for example, by arc welding, by plasma welding, for example with a filler wire, by MIG (metal inert gas) welding or by MIG / MAG (metal active gas) welding.

[0121] According to one embodiment, as shown in FIG. 2, the welded assembly 1 is a tube section 7 comprising a sheet metal 9 folded into the shape of a tube, the longitudinal edges 12 of which are welded together from the filler wire defined above. Bead 15. In such a case, the part 3 includes the longitudinal edges 12 of the sheet metal 9.

[0122] The wall of the tube section 5 has a thickness comprised between 3 mm and 60 mm, for example.

[0123] The tube section 5 is intended in particular to transport corrosive products, more particularly gas or oil, and more particularly to form part of a pipeline, in particular to be laid on the seabed, more particularly at depths up to a depth of the order of 3,000 m.

[0124] A further subject of the invention is a manufacturing method for such a tube section 5.

[0125] The method comprises the step of providing a metal sheet 9 made of a base metal. Such a metal sheet 9 is shown in Figure 3. The metal sheet 9 extends along a longitudinal direction L and has longitudinal edges 12 substantially parallel to the longitudinal direction L. For example, the metal sheet has a thickness comprised between 3 mm and 60 mm.

[0126] The method further comprises the step of folding the metal sheet 9 so that the two longitudinal edges 12 face each other, and thereafter welding the two longitudinal edges 12 facing each other using the welding method defined above. In such a case, the portion of the component 3 described in the context of the welding process comprises the longitudinal edges 12 of the metal sheet 9.

[0127] The welds produced during such processes are longitudinal welds. Preferably the welds are butt welds.

[0128] At the end of such a process, a tube section 7 is obtained as shown in Figure 2. The sheet metal 9 is folded into the shape of a tube, and the longitudinal edges 12 of the sheet metal 9 are welded together with the filler wire defined above. Bead Joined together by 15.

[0129] According to another embodiment, as shown in FIG. 4, the welded assembly is a tube 20, the part 3 being welded from the filler wire defined above. Bead 22. In such an embodiment, the tube sections 7 are connected together by welds 22. Bead 22 extends around the circumference of the tube 20 to connect the tube sections 7 together.

[0130] The weld is in particular a butt weld, and preferably an orbital weld, which refers to a weld produced by rotating a welding tool, more particularly a welding torch, relative to the tube section 7 to be welded.

[0131] The wall 20 has a thickness comprised between 3 mm and 60 mm, for example.

[0132] According to one embodiment, the tube section 7 is a tube section as described above.

[0133] According to a variant, the part of component 3 is a tube section that does not include any longitudinal welds and is obtained, for example, by billet extrusion.

[0134] The tube 20 is intended in particular to transport corrosive products, more particularly gas or oil, and more particularly to form parts of pipelines, in particular to be laid on the seabed, more particularly at depths of up to about 3,000 m.

[0135] A further subject of the present invention is thereby a manufacturing method for the tube 20 defined above.

[0136] During such a process, at least two tube sections 7 are provided. Each tube section 5 is substantially cylindrical and has an axis M and two longitudinal ends 24 spaced apart along the direction of the axis M.

[0137] The two tube sections 7 are then positioned in such a way that their longitudinal ends 24 face each other along the direction of the tube section axis M, and the facing longitudinal ends 24 of the two tube sections 7 are then welded together using the welding method defined above. In such a case, the part of the component 3 defined in the context of the welding process includes the longitudinal ends 24 of the tube sections 7.

[0138] Advantageously, during such a process, a butt weld is produced between the longitudinal ends 24 facing the tube sections 7. The weld is preferably an orbital weld.

[0139] Preferably, the welding process includes machining a chamfer into the ends 24 of the tube sections 7 that will be welded together before joining the tube sections 7 together.

[0140] The welding process is performed a number of times equal to the number of tube sections 7 to be welded to form the tube 20 minus one.

[0141] In one embodiment, the tube section 7 is the tube section 7 described above.

[0142] In a variant, the method can be carried out on any type of tube section the longitudinal ends of which are made of base metal, whatever the method by which the tube section is obtained: more particularly, the method is carried out on tube sections which do not include longitudinal welds and which are more particularly obtained by billet extrusion.

[0143] The method is more particularly carried out, for example, on a barge located at the location where the tube 20 is to be installed.

[0144] At the end of the welding process, a tube 20 is obtained, which is made of a welded material produced from the filler wire defined above. Bead The tube assembly includes at least two consecutive tube sections 7 assembled together by a connecting member 22.

[0145] The present invention further relates to a coated component 26 shown in Figure 5, which includes a substrate 28 made of a base material coated with a coating 30 made of the alloy described above. The base material is a metallic material.

[0146] The base material is in particular carbon steel, preferably X56, X60, or X65, or X70 steel.

[0147] Coating 30 is applied to substrate 28 by a process of hard surfacing, more particularly by welding with a filler wire having the composition described above.

[0148] The coating 30 has more particularly a thickness comprised between 2 mm and 20 mm.

[0149] Such a coating 30 improves the coated component's resistance to corrosion, particularly in the presence of corrosive products such as petroleum products.

[0150] The coated part 26 is in particular a coated tube section 7, with a coating 30 formed on the inner wall of the tube section 7, in particular by welding, if present. Bead 12. The inner wall of the tube section 7 is covered over its entire surface, including the inner wall 12.

[0151] The present invention further relates to a method for producing the coated component 26 described above, comprising providing a substrate 28 made of a base material, and then applying a coating 30 to a surface of the substrate by a weld hard surfacing process using a filler wire having the composition described above.

[0152] When the coated component 26 is a section of coated tube 7, the manufacturing method more particularly includes the steps of manufacturing the tube section 7 by implementing the method described above, and then applying the coating 30 to the inner surface of the tube section 7 by a process of hard surfacing by welding using a filler wire having the composition described above.

[0153] Coating 30 improves the resistance of tube section 7 to corrosion, for example during the transport of volatile and corrosive petroleum products.

[0154] According to a particular embodiment, the tube 20 described above is welded. Bead It comprises two tube sections 7 joined together by 22 and coated with the coating 30 described above.

[0155] The present invention further provides a method for manufacturing a component 40, shown schematically in FIG. 6, made from the alloy described above, comprising: - providing a filler wire made of the alloy; - manufacturing the component 40 by a metal additive manufacturing process using, as filler material, a filler wire made of the above-mentioned alloy and / or a powder made of the above-mentioned alloy; The present invention relates to a method, including:

[0156] Additive manufacturing processes are, for example, additive manufacturing processes that use an electric arc, a laser beam, and / or an electron beam as an energy source to melt a filler material.

[0157] The additive manufacturing process is in particular a directed energy deposition additive manufacturing process, during which a filler material is deposited, in particular through a nozzle, and is instantly melted by focused thermal energy, in particular by a laser beam, an electron beam, and / or an electric arc.

[0158] By way of example, the additive manufacturing process is a wire-arc, wire-laser, electron beam-wire ("electron beam freeform fabrication") process, or a hybrid additive manufacturing process combining wire-arc and laser-powder techniques or wire-arc and wire-laser.

[0159] When a hybrid additive manufacturing process combining wire-arc and laser-powder or wire-arc and wire-laser techniques is used, the powder and filler wire are made from the alloys mentioned above.

[0160] The additive manufacturing processes mentioned above are known per se and therefore will not be described in detail.

[0161] When the filler material comprises a powder, particularly in the context of a hybrid wire-arc and laser-powder process, the process further comprises the step of providing a powder made of the above-mentioned alloy before the manufacture of the component 40. The powder, whose particle size distribution after screening is between 20 μm and 150 μm, is produced, for example, by plasma spraying from a wire made of the above-mentioned alloy, more particularly a wire having a diameter of about 3 mm.

[0162] The plasma spraying process is known per se and will therefore not be described in detail.

[0163] The present invention also relates to a component 40 or portion of a component made from the alloy described above, produced by metal additive manufacturing.

[0164] Metal additive manufacturing processes more particularly use, as filler materials, filler wire made of the above-mentioned alloys and / or powder made of the above-mentioned alloys.

[0165] Additive manufacturing processes are additive manufacturing processes that use, for example, an electric arc, a laser beam, and / or an electron beam as an energy source to melt a filler material.

[0166] The additive manufacturing process is in particular a directed energy deposition additive manufacturing process, during which a filler material is deposited, in particular through a nozzle, and is instantly melted by focused thermal energy, in particular by a laser beam, an electron beam, and / or an electric arc.

[0167] By way of example, the additive manufacturing process is a wire-arc, wire-laser, electron beam-wire ("electron beam freeform fabrication") process, or a hybrid additive manufacturing process combining wire-arc and laser-powder techniques or wire-arc and wire-laser.

[0168] When a hybrid additive manufacturing process combining wire-arc and laser-powder or wire-arc and wire-laser techniques is used, the powder and filler wire are made from the alloys mentioned above.

[0169] A part or part portion obtained by a metal additive manufacturing process, such as part 40, remains solidified and therefore has a solidification microstructure typical of the nickel alloy considered, which typically includes columnar dendrites that grow epitaxially on top of each other, and whose orientation is proportional to the width of the resulting metal wall. and heightFurthermore, a part obtained by an additive manufacturing process has a series of solidified layers superimposed by the additive manufacturing process. Each layer, obtained by solidification of deposited droplets of molten metal, melts the skin of the previous layer and subsequently heats the remainder of the layer below in order to generate metallurgical continuity. The reheating temperatures are all lower since the layer in question is far from the zone undergoing melting and solidification. Such specific microstructures can be observed by metallographic observation of metallographic sections of the part.

[0170] Thus, a part 40 or part portion produced by a metal additive manufacturing process can be distinguished from parts produced by other methods, and in particular from parts produced by conventional metallurgy, which produces a recrystallized structure with homogeneous grains.

[0171] The component 40 or part of a component is particularly intended for the aeronautical, transport or energy markets. The component or part of a component may, for example, form a case, a frame, a tube with a complex shape, a valve, a mounting lug or a part of a component having a specific function. By way of example, a part of such a component may form a heat exchange element including channels for the circulation of a fluid, formed, for example, by additive manufacturing on a support component, which support component may, for example, be made of a material different from that of the heat exchange element.

[0172] test In a first series of tests, the inventors carried out laboratory castings to produce ingots of alloys having the compositions defined above, as well as comparative alloys having compositions different from those described above.

[0173] The alloy was produced under vacuum and the ingots so produced were converted by hot rolling to obtain sheet bars with dimensions of 10 x 50 x 300 mm.

[0174] The alloy compositions of each of the tested sheet rods are shown in Table 1 below.

[0175] The inventors then performed the following tests on the sheet bars so produced.

[0176] In some of the sheet bars, the inventors created joint fusion lines before and after with a TIG torch to generate solidified structures at the thickness of the sheet bar equivalent to those created by TIG or MIG welding under undiluted conditions, and sampled tensile and elasticity specimens from the fusion zone.

[0177] We then performed the following: - Elongation Rp of 0.2% at 20°C for the above-mentioned tensile test specimens according to standard NF EN ISO 6892-1 (December 2019) 0.2 Mechanical flat tensile test at room temperature (20°C) to measure the yield strength at Rp. The test results are reported in Table 2 below. 0.2 " column. - Elasticity tests at room temperature (20°C) on the elastic test specimens mentioned above, with the measurement of the impact fracture energy (denoted KCV) according to standard NF EN ISO 148-1 (January 2011). The fracture energy is expressed in J / cm 2 The fracture energy is expressed in units of kJ. The fracture energy reflects the elasticity of the part. The test results are summarized in the "KCV" column of Table 2 below.

[0178] We also measure the surface fraction of the phases precipitated during the solidification of the molten metal under the passage of the TIG torch in the melting zone of the sheet rod. The surface fraction of the precipitated phases is determined by image analysis of images of the sheet rod obtained with a scanning electron microscope (SEM). In fact, the precipitated phases correspond to the white areas of the image and are detected by image processing software, which uses grayscale analysis to detect the white areas and then determines the surface fraction occupied by the white areas. The results of the measurements are summarized in the "FS" column of Table 2 below.

[0179] The inventors also carried out Varestraint tests according to the European Standard FD CEN ISO / TR 17641-3 (November 2005) under a plastic deformation of 3.2% on sheet bars that had not been subjected to a joint fusion line in order to evaluate their resistance to hot cracking, together with measuring the total length of the crack that occurred during the test. The results of the tests are shown in Table 2 below under "L 合計 These are summarized as "cracks."

[0180] Finally, we carried out potentiometric titration tests to test the resistance of the alloy to localized corrosion. For this, we used 11.9 mol.l of HCl at pH 5.4 and 30°C. -1 The pitting potential V in LiCl medium at 200°C was measured and calculated as the pitting potential V of Inconel® 625 (V Inconel 625 / SCE <120 mV), where SCE is the reference potential relative to a saturated calomel electrode.

[0181] In Tables 1 and 2 below, tests not according to the present invention are underlined.

[0182] [Table 2A]

[0183] [Table 2B]

[0184] In the alloys of Table 1, the Al content is between 0.01 and 0.35%, the N content is comprised 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%. Furthermore, the alloys do not contain niobium.

[0185] For the alloys in Table 1, the remainder is nickel and impurities resulting from manufacturing.

[0186] Additionally, all compositions are given as mass percentages.

[0187] [Table 3A]

[0188] [Table 3B]

[0189] Furthermore, during potentiometric titration tests, alloys A1 to A28 in Table 1 developed pitting potentials V, relative to a reference potential versus a saturated calomel electrode, greater than or equal to 150 mV. Thus, the alloys have better resistance to localized corrosion than Inconel® 625 alloy.

[0190] As mentioned above, preferably the following properties: - yield strength Rp greater than or equal to 500 MPa 0.2 , - 100J / cm 2 KCV elasticity greater than or equal to - total length of crack less than or equal to 20 mm, - a surface proportion of precipitated phase FS of less than or equal to 1.5%; - Resistance to localized corrosion greater than or equal to that of Inconel® 625 alloy are calculated in combination.

[0191] Among the above parameters, the total crack length represents the weldability of the alloy. Since the total crack length for Inconel® 625 alloy is equal to 20 mm, a total crack length less than or equal to 20 mm corresponds to a weldability greater than or equal to the weldability of Inconel® 625 alloy and is therefore satisfactory for the considered application.

[0192] Such 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 with the compositions described above.

[0193] On the other hand, the yield strength Rp 0.2 is less than or equal to 500 MPa for Comparative Examples A1, A7, A18, A24, but the KCV elasticity is insufficient and / or the crack length is too long for Comparative Examples A5, A6, A12, A13, A17, A22, A23, A27, A28. In the context of the counterexamples, it should be noted that the relationship -0.5 x (Cr + Fe) + 25% < Mo + W < -0.5 x (Cr + Fe) + 30% is not satisfied.

[0194] Furthermore, as illustrated by Comparative Examples A6, A13, A17, A23, and A28, alloys containing iron at levels greater than 1.0% exhibit deteriorated ductility and increased susceptibility to hot cracking.

[0195] In general, we believe that a surface fraction of precipitated phase FS greater than 1.5% is less than 100 J / cm 2 It was found that this resulted in a KCV modulus of less than 1000 kJ and / or a crack length greater than 20 mm.

[0196] The inventors also conducted a second series of tests under the same conditions as those described for the first series of tests, but with the sheet bars made from alloys having the compositions summarized in Table 3. Furthermore, the results of the tests conducted on the sheet bars are shown in Table 4.

[0197] [Table 4]

[0198] In the alloys of Table 3, the Al content is between 0.01 and 0.35%, the N content is comprised 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%. Furthermore, the alloys do not contain niobium.

[0199] For all alloys in Table 3, the remainder is nickel and impurities resulting from manufacturing.

[0200] Additionally, all compositions are given as mass percentages.

[0201] [Table 5A]

[0202] [Table 5B]

[0203] Furthermore, during potentiometric titration tests, alloys B1 to B28 in Table 3 developed pitting potentials V, relative to a reference potential versus a saturated calomel electrode, greater than or equal to 150 mV. Thus, the alloys have better resistance to localized corrosion than Inconel® 625 alloy.

[0204] It has thus been found that the desired properties in terms of yield strength, elasticity, weldability, surface proportion of precipitated phases and resistance to localized corrosion are obtained in the case of Examples B2 to B4, B8 to B11, B14 to B16, B19 to B21, B25 and B26, which correspond to alloys having the compositions described above.

[0205] Other results confirm the conclusions drawn from Table 2.

[0206] In detail, the yield strength Rp 0.2is less than or equal to 500 MPa for Comparative Examples B1, B7, B18, B24, while the KCV elasticity is insufficient for Comparative Examples B5, B6, B12, B13, B17, B22, B23, B27, B28. Note that in the context of the counterexample, the relationship -0.5 x (Cr + Fe) + 25% < Mo + W < -0.5 x (Cr + Fe) + 30% is not satisfied.

[0207] Furthermore, weldability and elasticity are degraded when the alloy contains iron in an amount greater than 1.0%.

[0208] Thus, further comparison of the results in Tables 2 and 4 shows that the addition of rare earths improves the alloy's resistance to hot cracking.

[0209] 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 deoxidizing and / or desulfurizing the molten pool during the welding operation, thus contributing to improved resistance to hot cracking.

[0210] The alloy according to the invention has a yield strength Rp greater than or equal to 500 MPa. 0.2 and 100J / cm 2 These alloys have a KCV modulus greater than or equal to a yield strength Rp of less than 500 MPa, such as alloys X56, X60, X65, and X70. 0.2 It can be used to obtain an overmatch of mechanical properties to base metals having a high weld strength, so that the characteristics of the weld can be ignored for the design of welded assemblies made from alloys such as the base material.

[0211] Additionally, the alloy exhibits: a resistance to corrosion greater than or equal to that of the comparative Inconel® 625 alloy; - Weldability greater than or equal to that of the comparative Inconel® 625 alloy.

[0212] Taking into account its properties, the alloy according to the invention is therefore particularly suitable for use as a filler material for manufacturing pipeline tubes intended for the transportation of oil or gas and suitable for laying in deep offshore waters, in particular at depths of up to about 3,000 m, at high production rates, in particular of the order of 2 km / day.

[0213] Given its good properties, the alloy according to the invention can also be used advantageously in the context of components such as those mentioned above. [Explanation of symbols]

[0214] 1 Welded Assembly 3 parts 5. Welding Bead 7 Tube Section 9. Sheet Metal 12 Vertical Edge 15 Welding Bead 20 tubes 22 Welding Bead 24 Vertical edge 26 Coated parts 28 Base material 30 Coating 40 parts

Claims

1. Composition by mass of: 16.5%≦Cr≦25.0% 11.0%≦Mo≦18.0% 2.0%≦W≦7.0% Fe≦1.0% Mo + W ≦ −0.5 × (Cr + Fe) + 30%, where Mo is the molybdenum content of the alloy in wt. %, W is the tungsten content of the alloy in wt. %, Cr is the chromium content of the alloy in wt. %, and Fe is the iron content of the alloy in wt. Mo+W≧−0.5×(Cr+Fe)+25%, where Mo is the molybdenum content of the alloy in wt.%, W is the tungsten content of the alloy in wt.%, Cr is the chromium content of the alloy in wt.%, and Fe is the iron content of the alloy in wt.%. Ti + Ta ≦ 0.80%, where Ti is the titanium content of the alloy in wt. % and Ta is the tantalum content of the alloy in wt. % 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%, 0.0010%≦Rare earth≦0.015% as needed and a silicon content of less than or equal to 0.25% in the presence of rare earths with a content comprised between 0.0010% and 0.015%; An alloy having a nickel content greater than or equal to 54%, the remainder being nickel and unavoidable impurities resulting from manufacturing.

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

3. 3. The alloy of claim 1 or 2, wherein the rare earth is selected from yttrium, cerium, and lanthanum, and mixtures thereof.

4. 4. The alloy of claim 3, wherein the rare earth is selected from yttrium or a mixture of cerium and lanthanum.

5. 10. A coated component (26) comprising a substrate (28) made of a base material and a coating (30) made of the alloy of any one of claims 1 to 4, wherein the base material is a metallic material.

6. 6. The coated part of claim 5, wherein the coated part (26) is a tube section (7).

7. A filler wire made of an alloy having a composition according to any one of claims 1 to 4.

8. 10. A welded assembly (1; 7; 20) comprising at least two parts (3; 12; 7) of components, each of said two parts consisting of a base material, the parts (3; 12; 7) of the components being joined together by a weld bead (5; 15; 22) obtained from a filler wire according to claim 7, the base material being selected from iron-nickel alloys, nickel alloys, and carbon steel.

9. 9. A welded assembly according to claim 8, wherein the welded assembly forms a tube section (7) comprising sheet metal bent into the shape of a tube, the longitudinal edges (12) of which form the portions (3) of the parts joined together by weld beads (15).

10. 10. A welded assembly according to claim 9, wherein the tube section (7) is provided on at least a portion of its inner surface with a coating (30) consisting of an alloy according to any one of claims 1 to 4.

11. 9. The welded assembly of claim 8, wherein the welded assembly forms a tube (20) including at least two tube sections (7), the tube sections (7) forming portions (3) of the component, and the weld bead (22) extending around the circumference of the tube (20).

12. 12. A method for producing a welded assembly (1; 7; 20) according to any one of claims 8 to 11, comprising the step of welding together two parts (3; 12.7) of a component using a filler wire according to claim 7.

13. A method for producing a welded assembly (7) according to claim 9 or 10, wherein the welding step is a step of welding together the longitudinal edges (12) of the metal sheets (9).

14. 12. A method of producing a welded assembly (20) according to claim 11, comprising, prior to the welding step, the following sequential steps: - providing a first tube section (7) and a second tube section (7), each extending along a longitudinal axis (M) and made of a base material; - positioning the first and second tube sections (7) such that the longitudinal end (24) of the first tube section (7) faces the longitudinal end (24) of the second tube section (7) along the longitudinal axis (M) of the first and second tube sections (7); Including, the welding step is a step of welding together two longitudinal ends (24) facing the first and second tube sections (7); method.

15. 5. A component or part of a component made from an alloy according to any one of claims 1 to 4.

16. 16. The part or part of a part of claim 15, wherein the part or part of a part comprises a series of overlapping solidified layers.

17. 10. A method of manufacturing a component or portion of a component, the method comprising manufacturing the component or portion of a component by a metal additive manufacturing process using, as filler material, a filler wire comprising the alloy of any one of claims 1 to 4, and / or a powder comprising the alloy of any one of claims 1 to 4.

18. Use of the filler wire according to claim 7, as a welding filler wire for welding together two parts of a component, the base material of which is an iron-nickel alloy, a nickel alloy, or carbon steel; and / or as a hardfacing wire for producing a coating on a component or part of a component, consisting of a base material that is a metallic material; and / or - as filler wire in metal additive manufacturing processes, use.

19. A metal powder consisting of an alloy according to any one of claims 1 to 4.

20. 20. A method of producing the metal powder of claim 19, comprising the steps of providing a filler wire of claim 7 and plasma spraying the filler wire to obtain the metal powder.

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