EP4237188A1

EP4237188A1 - Nickel-based alloy for manufacturing pipeline tubes

Info

Publication number: EP4237188A1
Application number: EP20803941.2A
Authority: EP
Inventors: Pierre-Louis Reydet; Fanny JOUVENCEAU
Original assignee: Aperam SA
Current assignee: Aperam SA
Priority date: 2020-10-30
Filing date: 2020-10-30
Publication date: 2023-09-06
Also published as: JP2023553255A; CA3196465A1; MX2023005043A; CN116615293A; WO2022090781A1; KR20230098270A

Abstract

The 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 ≤ - 0.5 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%; optionally 0.0010% ≤ rare earths ≤ 0.015%, the silicon content being less than or equal to 0.25% in the presence of rare earths in an amount between 0.0010% and 0.015%, the balance being nickel and inevitable impurities resulting from the processing, the nickel content being greater than or equal to 54%.

Description

NICKEL-BASED ALLOY FOR MAKING PIPELINE TUBES

The present invention relates to a nickel-based alloy intended for use in particular in the field of petrochemistry and the extraction of petroleum products, and more particularly in the context of the manufacture of pipeline tubes for the transport of gas or oil.

The exploitation of gas and oil requires the laying of pipelines at sea. For reasons of productivity and economic profitability, it is desired to lay these pipelines at a laying speed of approximately 2 km/day. There are currently three technologies available to meet these productivity constraints:

• S-Lay technology: the sections of tube, typically 9 m or 12 m long, are manufactured on land in units called "spoolbase", then transported to sea on ships to be butt-welded. end horizontally on a barge. The pose is called 'S' to recall the shape taken by the tube before touching the seabed. This technology is suitable for depths of less than 2000 m.

• J-Lay technology: This technology is more recent and adapted to deep waters (2000 m to 4000 m). The pipe sections are welded together at sea on a vertical barge (at a slight angle) and form a ‘J’ shape before touching the seabed.

• R-Lay technology: The most recent, it is dedicated to small diameter tubes and shallow waters. The line of tubes is entirely welded on land, then rolled up on a wheel to be transported to sea before being unrolled there by means of specific barges. This technology is the most efficient.

These laying techniques impose mechanical stresses on the pipes, and in particular on the orbital welds between pipe sections, in particular under the effect of the bending of the pipe during laying and under the effect of its own weight before touching the seabed. The tubes, and in particular the welds, must therefore be designed in such a way as to resist these stresses in order to avoid deformation of the tubes during the laying phases.

In addition to the constraints in terms of laying speed, there is also a necessary increase in laying depths in order to seek the deposits still available, these laying depths being able to go up to approximately 2500 m to 3000 m deep. This increase in the laying depth increases the mechanical stresses exerted on the tubes, and therefore requires the use of carbon steels with increasingly high mechanical properties.

The pipe sections used are typically manufactured in the workshop by rolling steel sheets and then longitudinally welding the edges of these sheets using the process MIG/MAG with a steel filler wire, the composition of which is chosen according to the grade of the sheets. The wall thickness of these tube sections is typically around 25 mm and their diameter is between 25 cm and 130 cm.

Alternatively, and depending on the application, the tube sections are manufactured by billet extrusion. The tube sections, as well as the tubes obtained by orbital welding of these tube sections, in this case have no longitudinal weld (“seamless tube”).

The mechanical resistance of the tube sections specified according to the grade of steel is recalled below, according to API Specification 5L, for steel grades X56, X60, X65, X70 or X80 likely to be used for the manufacture of these pipe sections. The steel grade corresponds to the elastic limit of the sheets, in ksi units.

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

In the case where the tube sections include a longitudinal weld, it is sought, during the manufacture of the tube sections, to obtain welds whose mechanical properties are greater than or equal to those of the steel of the base sheet (" overmatching") so as to be able to size the sections of tube, and for example define the thickness of the sections of tube and the grade of steel used, according to the laying conditions (S, J, R) and the type of operation of the line only without being forced to take welds into account.

In the case where the pipe sections are manufactured without longitudinal welding, for example by extrusion of billets (“seamless” technology), it is possible to dispense with the specifications required for longitudinal welds (“overmatching”).

After manufacture of the tube sections, the inner surface of the tube sections, including any longitudinal welds, is coated with a coating layer by resurfacing by welding by means of a filler wire. This operation of The purpose of the coating is to ensure the corrosion resistance of the tube during the transport of more or less corrosive petroleum products. The interior coating is typically made of Inconel ® 625 alloy. Inconel ® 625 alloy has the following composition, by weight:

Cr: 20.0-23.0%

Fe < 5.0%

MB: 8.0-10.0%

Nb+Ta: 3.15-4.15%

C S 0.10%

Min S 0.50%

If S 0.50%

PS 0.002%

S S 0.015%

Al S 0.40%

Ti S 0.40%

Other elements S 0.5%, the rest being nickel and unavoidable impurities resulting from the elaboration, with Ni > 58%.

The Inconel ® 625 alloy is defined in Table 1 of the AWS A5.14/A5.14M: 2018 standard (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 (UNS number N06625).

Once manufactured, the pipe sections are transported on a barge and butt-welded by orbital welding as they are laid by one of the techniques mentioned above.

Whatever the laying technique used, the butt welds (orbital) made between the pipe sections must withstand the bending stresses of the line during laying and its own weight before touching the seabed. The mechanical strength of the orbital welds is therefore of primary importance in order to avoid the deformation of the welds during the installation phases.

In general, the following properties are sought for orbital welds between pipe sections:

- Overmatching: the aim is to obtain orbital welds with a mechanical strength greater than or equal to that of the base metal, that is to say the steel of the tube section. As mentioned above with respect to the longitudinal welds of the tube sections, this overmatching makes it possible to size the tubes, and in particular to define the thickness of the tube and the grade of steel used, depending on the laying conditions (S, J, R) and the type of operation of the line without being forced to take welds into account.

- Resistance to localized corrosion greater than or equal to that of the coating of the tube section, on the inside, in order to be able to size the tubes in relation to the constraints in terms of resistance to localized corrosion without taking into account the existence of orbital welds .

Throughout the description, localized corrosion means corrosion likely to develop pitting mechanisms.

In order to meet all the constraints mentioned above, it has been proposed to produce orbital welds in which the root pass, at the level of the coating, is carried out by means of an Inconel alloy filler wire. ® 625, and to finish the weld with steel filler passes of a grade equivalent to the base metal. This welding technique guarantees good mechanical properties because it ensures a certain continuity of the materials used. On the other hand, it poses significant problems of hot cracking, and therefore of weldability, linked to the dilution of the Inconel ® 625 alloy. Such a solution is therefore not entirely satisfactory. In particular, the cracks appearing during welding must be repaired, which generates a significant additional cost. In addition, if they are not repaired, these cracks risk causing the tubes to break in operation.

It has also been proposed to carry out the entire weld using a single Inconel ® 625 alloy wire. This welding solution is therefore economical. In addition, it generates no hot cracking problem, and leads to corrosion resistance comparable to that of the coating. Also, it is widely used to weld tubes up to grade X56 or even X60. However, this is no longer suitable for higher grades of steel (X65, X70 and X80). However, the constraints mentioned above, in particular in terms of speed and depth of laying, increasingly require the use of steels of grades higher than grade X60, and in particular steel of grade X65, or even X70 .

An object of the invention is therefore to overcome the above drawbacks and to provide an alloy capable of being used as a filler material for the manufacture of pipeline tubes intended for the transport of oil or gas and suitable for laying in the open sea at great depths, and in particular up to a depth of about 3000 m, at high rates, in particular of the order of 2 km/day.

The laying of the tubes at depths that can go up to about 3000 m deep, as well as the high laying rates, require the use of a steel with high mechanical properties. Preferably, with regard to the mechanical properties of the welded assemblies, the aim is to obtain, at a minimum: an elastic limit Rpo,2 greater than or equal to 500 MPa and a KCV resilience greater than or equal to 100 J/cm ² , and advantageously an elastic limit Rpo,2 greater than or equal to 550 MPa and/or a KCV resilience greater than or equal to 120 J/cm ² .

In addition, the use of tubes as pipelines for the transport of oil or gas requires good resistance to corrosion of the filler material, as well as good weldability. In particular, localized corrosion resistance and weldability greater than or equal to those of the Inconel ® 625 alloy are sought.

To this end, the subject of the invention is an alloy having the following composition, by weight:

16.5% Cr<S 25.0%

11.0% MB 18.0%

2.0% S W S 7.0%

FeS 1.0%

Mo+W S - 0.5x (Cr+Fe) + 30%

Mo+W > - 0.5x (Cr+Fe) + 25%

Ti+Ta 0.80%

0.01% < If < 0.75%

0.01% < Al < 0.35%

0.01% < Mn < 0.35%

Ca < 0.005%

Mg<0.005%

Count < 0.01%

0.001%<C<0.05%

0.001% < N < 0.05%

S<0.003%

P < 0.005% optionally, 0.0010% S rare earths S 0.015%, the silicon content being less than or equal to 0.25% in the presence of rare earths at a content of between 0.0010% and 0.015%, the remainder being nickel and unavoidable impurities resulting from the production, the nickel content being greater than or equal to 54%.

The alloy according to the invention may also comprise one or more of the following characteristics, taken individually or in any technically possible combination(s): - the iron content is less than or equal to 0.5%;

- the rare earths are chosen from yttrium, cerium and lanthanum and mixtures of these elements; and

- the rare earths are chosen from yttrium or a mixture of cerium and lanthanum.

The invention also relates to a coated part comprising a substrate made of a base material and a coating made of an alloy according to any one of claims 1 to 4, the base material being a metallic material, preferably a carbon steel. carbon, and for example a steel X56, X60, X65, X70.

According to a particular example, the coated part is a section of tube.

The invention also relates to a filler wire made of an alloy as described above.

The invention also relates to a process for manufacturing the filler wire described above, comprising the following steps:

- supply of a semi-finished product made from an alloy as described above;

- hot transformation of this semi-finished product to form an intermediate yarn; and

- transformation of the intermediate wire into filler wire, of smaller diameter than that of the intermediate wire, said transformation comprising a drawing step.

The invention also relates to a welded assembly comprising at least two parts of parts, each made of a base material, the parts of parts being linked together by a weld bead obtained from the filler wire as described below. above, the base material being chosen from an iron-nickel alloy of the Fe-9Ni type, a nickel-based alloy of the C-276, C-4 or 22 type and a carbon steel, for example an X56, X60 steel , X65 or X70.

The welded assembly according to the invention may also include one or more of the following characteristics, taken separately or in any technically possible combination(s):

- the welded assembly forms a section of tube comprising a sheet folded in the shape of a tube, the longitudinal edges of which constitute the parts of the part linked together by the weld bead;

- the tube section is provided with a coating made of the alloy as described above, on at least part, and preferably all, of its inner surface; and

- the welded assembly forms a tube comprising at least two tube sections, the tube sections constituting the part parts, and the weld bead extending along the circumference of the tube, the tube sections preferably being tube sections as described above.

The invention also relates to a method of manufacturing a welded assembly comprising the welding together of the two parts of the parts by means of the filler wire as described above, the welding being in particular arc welding.

The manufacturing process of the welded assembly may also include one or more of the following characteristics, taken individually or in any technically possible combination(s):

- the welding step is a step of welding together the longitudinal edges of the sheet, the weld preferably being a longitudinal butt weld; and

- the method further comprises, before the welding step, the following successive steps:

- supply of a first section of tube and a second section of tube each extending along a longitudinal axis, and made of the base material;

- Positioning of the first and second tube sections such that a longitudinal end of the first tube section is arranged opposite a longitudinal end of the second tube section along the longitudinal axis of the first and second tube sections; and the welding step being a step of welding together two longitudinal ends facing the first and second tube sections, the welding preferably being an orbital butt welding.

The invention also relates to a part or part of a part made of an alloy as described above, said part or part of a part being obtained by additive manufacturing.

This additive manufacturing process uses, in particular, as filler material, a filler wire made from the alloy as described above and/or a powder made from the alloy as described above. .

The additive manufacturing process is, for example, an additive manufacturing process using an electric arc, a laser beam and/or an electron beam as an energy source to achieve the melting of the filler material.

By way of example, the additive manufacturing process is an arc-wire, laser-wire, electron beam-wire process or a hybrid additive manufacturing process combining arc-wire and laser-powder or arc-wire and Laser-wire. The invention also relates to a process for manufacturing a part or part of a part comprising a step of manufacturing said part or part of a part by a metal additive manufacturing process using, as filler material, a wire of contribution made in the alloy as described above and/or a powder made in the alloy as described above.

By way of example, the additive manufacturing process is an arc-wire, laser-wire, electron beam-wire process or a hybrid additive manufacturing process combining arc-wire and laser-powder or arc-wire and Laser-wire.

The invention also relates to a use of the filler wire as described above:

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

- As a hardfacing wire for producing a coating on parts or parts of parts made of a metallic base material, the base material preferably being a carbon steel, and for example an X56, X60, X65 or X70 steel; and or

- as filler wire in a metal additive manufacturing process.

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

The invention also relates to a process for manufacturing the metal powder produced in an alloy as described above.

The invention will be better understood on reading the following description, given solely by way of example, and made with reference to the appended drawings, among which:

- Figure 1 is a schematic sectional view of a welded assembly according to the invention;

- Figure 2 is a schematic perspective view of a tube section according to the invention; - Figure 3 is a schematic top view of a sheet used during the implementation of the method of manufacturing a tube section;

- Figure 4 is a schematic perspective view of a tube according to the invention;

- Figure 5 is a schematic perspective view of a part coated according to the invention; and

- Figure 6 is a schematic perspective view of a part obtained by additive manufacturing according to the invention.

In the rest of the description, all the contents are expressed in percentage by weight.

The alloy according to the invention has the following composition, by weight:

16.5% Cr<S 25.0%

11.0% S Mo 18.0%

2.0% S W S 7.0%

FeS 1.0%

Mo+W S - 0.5x (Cr+Fe) + 30%

Mo+W - 0.5x (Cr+Fe) + 25%

Ti+Ta 0.80%

0.01% < If < 0.75%

0.01% < Al < 0.35%

0.01% < Mn < 0.35%

Ca < 0.005%

Mg<0.005%

Count < 0.01%

0.001%<C<0.05%

0.001% < N < 0.05%

S<0.003%

By unavoidable impurities resulting from the production, we mean elements which are present in the raw materials used to produce the alloy or which come from the apparatus used for its production, and for example from the refractories of the furnaces. These residual elements have no metallurgical effect on the alloy. In this alloy, the nickel content greater than or equal to 54% by weight ensures good ductility of the matrix and good resistance to corrosion under stress.

At a content of between 16.5% and 25.0% by weight, chromium provides good resistance to generalized corrosion and improves the mechanical properties of the alloy. In particular, the inventors have observed that the resistance to generalized corrosion is insufficient when the chromium content is less than 16.5% by weight. On the other hand, a chromium content higher than 25.0% by weight results in a precipitation of the a-phase, associated with a loss of ductility and an increased sensitivity to hot cracking, and thus results in degraded mechanical properties of the chromium. 'alloy.

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

Present at contents of between 11.0% and 18.0% by weight, molybdenum improves resistance to localized corrosion.

Furthermore, molybdenum considerably improves the mechanical properties. The inventors have found that, for molybdenum contents of less than 11.0% by weight, the resistance to localized corrosion and the mechanical properties are insufficient, while a molybdenum content greater than 18% results in a precipitation of the phases resulting in loss of ductility and increased susceptibility to hot cracking.

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

The tungsten content is between 2.0% and 7.0% by weight. Present at these levels, tungsten also improves resistance to localized corrosion. In addition, it improves the mechanical properties. The inventors have observed that, for tungsten contents of less than 2.0%, the resistance to localized corrosion is insufficient. On the other hand, a tungsten content greater than 7.0% results in precipitation of undesirable phases, resulting in loss of ductility and increased susceptibility to hot cracking.

The iron content is less than or equal to 1.0% by weight. The addition of iron deteriorates resistance to generalized corrosion. An iron content less than or equal to 1.0% by weight allows the production of the alloy by means of scrap materials containing a residual iron content, which makes it possible to reduce the production cost. At a content greater than 1.0% by weight, it also promotes the precipitation of undesirable phases, resulting in a loss of ductility and an increased sensitivity to hot cracking.

Preferably, the iron content in the alloy is less than or equal to 0.5% by weight. The sum of the titanium and tantalum contents is less than or equal to 0.80% by weight. Present at the claimed contents, titanium and tantalum considerably improve the mechanical properties, but their low solubility in Ni-Cr alloys generates precipitations of undesirable phases. Also, their contents must be limited to low concentrations. However, they contribute to the deoxidation of the alloy during production. The inventors have observed that, when Ti + Ta greater than 0.80% by weight, the precipitation of undesirable phases is observed, resulting in a loss of ductility and an increased sensitivity to hot cracking.

According to the invention, Mo + W - 0.5 x (Cr+Fe) + 30% by weight. The inventors have found that compliance with this relationship makes it possible to obtain satisfactory ductility, resulting in particular in a fracture energy KCV S 100J/cm ² , as well as good weldability, resulting in a total length of cracks less or equal to 20 mm.

The fracture energy KCV is expressed in J/cm ² . It reflects the resilience of the piece. It is for example determined by resilience tests carried out in accordance with standard NF EN ISO 148-1 (January 2011) at ambient temperature.

The length of the cracks is in particular determined by Varestraint tests according to the European standard FD CEN ISO/TR 17641-3 (November 2005) under 3.2% plastic deformation.

Further, Mo + W > - 0.5 x (Cr+Fe) + 25 wt%. The inventors have observed that compliance with this relationship makes it possible to obtain satisfactory mechanical strength, and in particular an elastic limit Rpo, 2 greater than or equal to 500 MPa.

At the contents mentioned above, silicon and aluminum favor deoxidation and manganese favor desulphurization during the elaboration of the alloy.

The calcium and magnesium contents in the alloy are each limited to 0.005% by weight so as not to degrade the weldability. In particular, the calcium and magnesium contents are limited so as not to degrade the quality of the weld beads and in particular the formation of surface slags producing arc and liquid bath instabilities.

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 degrade the resistance to hot cracking. In particular, niobium segregates strongly in the interdendritic spaces and promotes the precipitation of undesirable phases.

The alloy also contains carbon and nitrogen in contents of between 0.001 and 0.05% by weight. The carbon is controlled in order to facilitate deoxidation during the elaboration of the alloy. In addition carbon and nitrogen also provide refinement microstructures by the precipitation of carbonitrides of the Ti-(C, N) type if they are associated with the addition of titanium.

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

Optionally, the alloy comprises rare earths at a content of between 0.0010 and 0.015% by weight. Rare earths trap sulfur and residual oxygen. They improve resistance to hot cracking when welding a base metal containing residual S+O contents higher than those of the welding wire. However, at a content higher than 0.015%, they favor the precipitation of low melting point eutectic phases, in particular in the presence of silicon, which results in a loss of ductility and an increased sensitivity to hot cracking.

The rare earths are preferably chosen from yttrium, cerium and lanthanum, or from mixtures of these elements.

According to one example, the rare earths consist of yttrium. In this case, the alloy comprises between 0.0010 and 0.015% by weight of yttrium.

According to a 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.

In the presence of rare earths at a content of between 0.0010 and 0.015% by weight, the silicon content is limited to 0.25% by weight, and preferably to 0.20% by weight. In this case, the silicon content is therefore between 0.01 and 0.25% by weight, and preferably between 0.01 and 0.20% by weight. Indeed, silicon promotes the formation of phases containing rare earths, which reduces the availability of rare earths to trap residual sulfur and oxygen.

The alloy according to the invention has a yield strength Rpo,2 of between 500 MPa and 600 MPa and a KCV resilience greater than or equal to 100 J/cm ² , which makes it possible to obtain ductile welds having an overmatching of the mechanical properties compared to a base material made of X56, X60, X65 or X70 steel.

As specified above, steel grades X56, X60, X65, X70 or X80 are defined in the document "API Specification 5L" of the American Petroleum Institute, ^45th edition of December 2012.

Furthermore, the alloy according to the invention has:

- good resistance to corrosion, and in particular resistance to localized corrosion greater than or equal to that of the comparative Inconel ® 625 alloy;

- a weldability greater than or equal to that of the comparative Inconel ® 625 alloy. Thus, the characteristics of longitudinal and/or orbital welds can be ignored for the design of welded assemblies intended to present an Rpo,2 yield strength greater than or equal to 500 MPa and a KCV resilience greater than or equal to 100 J/cm ² , and comprising in particular steels X56, X60, X65 and X70 as base materials.

Given its properties, the alloy according to the invention is therefore particularly suitable for use as a filler material for the manufacture of pipeline tubes intended for the transport of oil or gas and suitable for laying on the high seas. at great depths, and in particular down to a depth of around 3000 m, at high rates, in particular of the order of 2 km/day.

This alloy can therefore be used advantageously as a filler material for carrying out the longitudinal and/or orbital welds of pipeline tubes made of X56, X60, X65 or X70 steel, and intended to be laid at significant depths, going for example up to 3000 m deep and for high laying rates.

Given its good corrosion resistance properties, it can also be used to produce the internal coating intended to improve the corrosion resistance of such tubes.

The alloy according to the invention can be produced by any suitable method known to those skilled in the art.

For example, in a first step, starting materials are placed in an electric arc furnace. These starting materials are chosen so as to obtain an alloy containing less than 1.0% by weight of iron. These are in particular new materials. Then, these starting materials are subjected to melting in the electric arc furnace, then ladle refining (VOD) is carried out by usual methods, in order to obtain:

- decarburization by oxygen blowing and vacuum pumping (of the order of a few mbar);

- deoxidation and desulfurization under lime-based slag; and

- adjustment of reducing elements such as Ti and Al.

The invention also relates to a filler wire made from an alloy having a composition as described above. Such a filler wire is in particular suitable for use in the context of TIG or plasma welding processes with filler wire or the MIG/MAG welding process.

It is for example intended to be used:

- as a welding filler wire for welding together two parts of parts made of a base material, the base material being in particular an iron-nickel alloy of the Fe-9Ni type, that is to say containing nickel with a content of between 5% and 10% by weight, or a nickel-based alloy of the C-276, C-4 or 22 type, or a carbon steel, and in particular an X56, X60, X65 or X70; and or

- as a hardfacing wire, to produce a coating, in particular on parts or parts of parts made of a base material, the base material being a carbon steel, and in particular an X56, X60, X65 or X70 steel.

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), titled “Chemical composition requirements for Nickel and Nickel-Alloy Electrodes and Rods” under the AWS classification reference ERNiCrMo-4 (UNS number N10276).

Alloy C-4 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-7 (UNS number N06455).

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 (UNS number N06022).

The parts or parts of parts are in particular tube sections, tubes and/or sheets or parts of sheets made from the base material.

The filler wire is for example also intended to be used as a filler wire in the context of a metal additive manufacturing process.

The additive manufacturing process is, for example, an additive manufacturing process using an electric arc, a laser beam and/or an electron beam as an energy source to achieve fusion of the filler wire.

The additive manufacturing process is in particular a Directed Energy Deposition additive manufacturing process. During this process, the filler material is deposited, in particular by a nozzle, and immediately fused by concentrated thermal energy, in particular a laser beam, an electron beam and/or an electric arc. By way of example, the additive manufacturing process is an arc-wire process (“WAAM” or “Wire arc additive manufacturing”), Laser-wire, electron beam-wire (“Electron Beam Free Form Fabrication”) or “Electron beam additive manufacturing” in English) or a hybrid additive manufacturing process combining arc-wire and Laser-powder or arc-wire and Laser-wire technologies

In the case of a hybrid arc-wire and Laser-powder process, the powder used has the same composition as the wire.

Such a powder, whose particle size after sieving is between 20 μm and 150 μm, is for example obtained from the filler wire according to the invention, by means of plasma atomization technology. Preferably, the filler wire used to manufacture the powder has a diameter of approximately 3 mm.

The particle size of the powders is determined in particular by the following measurement method. Powder batches are separated into multiple powder size distributions by means of ultrasonically vibrating stainless steel sieves. The analysis of the distribution of the sizes of the powders resulting from the sievings is carried out according to the standard ASTM B214-07. Sieving makes it possible to obtain 5 size classes: < 20pm - 20pm to 45pm - 45pm to 75pm - 75pm to 105pm - >105pm.

Plasma atomization technology for making a powder from a wire is known per se, and therefore is not described in more detail.

The parts or parts of parts are intended in particular for the aeronautics, transport or energy market. They constitute, for example, casings, frames, tubes with complex shapes, valves, fixing lugs, or parts of parts having particular functions. By way of example, such a part of the part constitutes a heat exchanger element comprising, for example, channels for the circulation of a fluid formed by additive manufacturing on a support part, the support part being for example made of a different material that of the heat exchanger element.

The invention also relates to a method of manufacturing a filler wire made of the alloy as described above.

This method comprises, in a first step, the supply of a semi-finished product produced in this alloy. For this purpose, the alloy is either cast in ingots, or cast directly in the form of billets, in particular by means of continuous casting, in particular rotary casting. The semi-finished products obtained at the end of this step are therefore advantageously ingots or billets, and have for example a diameter of between 130 and 230 mm, and more particularly equal to approximately 150 mm. Then, the semi-finished products are transformed by hot transformation to form an intermediate yarn.

In particular, during this hot transformation step, the semi-finished products, that is to say in particular the ingots or billets, are heated, in particular in a gas oven, to a temperature of between 1180° C and 1220°C.

They are then subjected to hot roughing so as to reduce their section, giving them, for example, a square section, of approximately 100 mm to 200 mm on each side. A semi-finished product of reduced section is thus obtained. The length of this semi-finished product of reduced section is in particular between 10 meters and 20 meters.

The reduced-section semi-finished products are then further hot-processed, at a temperature of between 1050 and 1150°C, to obtain the intermediate wire. The intermediate wire may in particular be a machine wire. It has for example a diameter of between 5 mm and 21 mm, and in particular approximately equal to 5.5 mm. Advantageously, during this step, the intermediate wire is produced by hot rolling on a wire mill.

Optionally, the intermediate wire is then subjected to annealing in a pool, after heat treatment in a gas oven, at a temperature of between 1150° C. and 1220° C. for a period of between 60 minutes and 120 minutes.

The intermediate wire is then pickled, then wound in the form of a coil.

Optionally, the intermediate wire thus obtained is drawn by means of a drawing installation of known type to obtain the filler wire. This filler wire has a smaller diameter than the starting wire. Its diameter is in particular between 0.5 mm and 3.5 mm. It is advantageously between 0.8 mm and 2.4 mm.

The drawing step comprises, depending on the final diameter to be reached, one or more drawing passes, with, preferably, annealing between two successive drawing passes. This annealing is for example carried out by scrolling under a reducing atmosphere at a temperature of the order of 1150°C.

The drawing step is preferably followed by cleaning the surface of the drawn wire, then by winding the wire.

The drawing passes are carried out cold.

All other methods for producing the alloy according to the invention and for manufacturing finished products made of this alloy known to those skilled in the art can be used for this purpose.

The invention also relates to a welded assembly 1 comprising at least two part parts 3, made of a base metal, linked together by a cord solder 5 obtained from the filler wire as described above. Such a welded assembly is represented schematically in FIG.

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

It should be understood that throughout the text by "parts of parts" welded together, we understand both the case where these parts welded together belong to two initially separate parts and the case where these parts are two parts of the same part folded back on itself, for example the two longitudinal edges of a sheet which are welded to form a tube.

The base metal is in particular a carbon steel, such as an X56, X60, X65 or X70 steel or an iron-nickel alloy of the Fe-9%Ni type, that is to say comprising a nickel content of between 5 and 10% by weight, or a nickel-based alloy of type C-276, C-4 or 22.

The invention also relates to a welding process for welding together at least two parts of parts 3 made of the base metal defined above so as to produce a welded assembly 5 as illustrated in FIG.

First, a filler wire is provided as previously described. Parts of parts 12 made of the base metal which it is desired to weld together by means of the welding process are also provided.

The parts of parts 12 are then welded together using the filler wire as welding filler wire. During this step, a butt weld is preferably made.

The welding step can include one or more welding passes. Conventionally, it includes a first welding pass called root pass, followed by one or more additional welding passes, called filling passes. All the welding passes are carried out using as filler wire the filler wire according to the invention, as described above. This limits the dilution of this filler wire to the dilution by the molten base metal resulting from the welding.

The welding is for example carried out by arc welding, for example by plasma welding with filler wire, by MIG ("Metal Inert Gas" in English) welding or by MIG/MAG ("Metal active gas" in English) welding. ).

According to one embodiment, shown in Figure 2, the welded assembly 1 is a section of tube 7 comprising a sheet metal 9 folded into the shape of a tube, the longitudinal edges 12 of which are linked together by a weld bead 15 obtained at from the wire contribution as defined above. In this case, the part parts 3 include the longitudinal edges 12 of the sheet 9.

The wall of the tube section 5 has for example a thickness of between 3 mm and 60 mm.

The tube section 5 is intended in particular for the transport of corrosive products, in particular gas or oil. It is in particular intended to form part of a pipeline, in particular installed on the seabed, and in particular at a depth of up to 3000 m.

The invention also relates to a method of manufacturing such a section of tube 5.

The method includes supplying a sheet 9 made from the base metal. Such a sheet 9 is shown in Figure 3. It extends in a longitudinal direction L and has longitudinal edges 12 substantially parallel to the longitudinal direction L. It has for example a thickness of between 3 mm and 60 mm.

The method further comprises a step consisting in folding this sheet 9 so as to bring the two longitudinal edges 12 facing each other, followed by a step consisting in welding together the two longitudinal edges 12 facing each other using the welding process defined previously. . In this case, the part parts 3 described within the framework of the welding process comprise the longitudinal edges 12 of the sheet 9.

The weld made during this step is a longitudinal weld. Preferably, it is a butt weld.

At the end of this process, a section of tube 7 is obtained, as illustrated in FIG. 2, in which the sheet 9 is folded into the shape of a tube, and the longitudinal edges 12 of the sheet 9 are bonded together. by a weld bead 15 obtained from the filler wire as defined above.

According to another embodiment, represented in FIG. 4, the welded assembly is a tube 20 and the part parts 3 are sections of tube 7 linked together by a weld bead 22 obtained from the filler wire as defined previously. In this embodiment, the weld bead 22 extends along the circumference of the tube 20 so as to connect the tube sections 7 together.

The weld is in particular a butt weld, preferably an orbital weld. By orbital weld, we mean a weld made by rotating the welding tool welding, namely in particular the welding torches, with respect to the tube sections 7 to be welded.

The wall of the tube 20 has for example a thickness of between 3 mm and 60 mm.

According to one embodiment, the tube sections 7 are tube sections as described previously.

According to a variant, the parts of parts 3 are sections of tube not comprising any longitudinal weld, and obtained for example by extrusion of billets.

The tube 20 is in particular intended for the transport of corrosive products, in particular gas or oil. It is in particular intended to form part of a pipeline, in particular installed on the seabed, and in particular at a depth of up to 3000 m.

Thus, the invention also relates to a method of manufacturing a tube 20 as described above.

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

The two sections of tube 7 are then positioned so that their longitudinal ends 24 are arranged facing each other in the direction of the axis M of these sections of tube, then the longitudinal ends 24 facing the two sections are welded together. tube 7 by means of the welding process as defined above. In this case, the part parts 3 defined within the framework of the welding process comprise the longitudinal ends 24 of the tube sections 7.

Advantageously, during this step, a butt weld is made between the longitudinal ends 24 facing the tube sections 7. The weld is preferably an orbital weld.

Preferably, the welding step comprises, prior to joining together the tube sections 7, a step of machining chamfers at the ends 24 of the tube sections 7 to be welded together.

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

According to one embodiment, the tube sections 7 are tube sections 7 as described previously.

As a variant, this method can be carried out with any type of section of tube whose longitudinal ends are made of the base metal, whatever the process for obtaining the tube section. In particular, this method is implemented on tube sections not comprising any longitudinal weld, and obtained in particular by extrusion of billets.

This method is in particular implemented on a barge, this barge being for example located at the place of installation of the tube 20.

At the end of this or these welding steps, the tube 20 is obtained. This tube 20 comprises at least two successive tube sections 7 assembled together by a weld bead 22 obtained from the filler wire such as previously defined.

The invention also relates to a coated part 26 as represented in FIG. 5 comprising a substrate 28 made of a base material coated with a coating 30 made of an alloy as described above. The base material is metallic material.

The base material is in particular a carbon steel. Preferably, the base material is an X56, X60 or X65 or X70 steel.

The coating 30 is in particular applied to the substrate 28 by a process of hardfacing by welding by means of a filler wire having the composition described above.

The coating 30 in particular has a thickness of between 2 mm and 20 mm.

Such a coating 30 improves the corrosion resistance of the coated part 26, in particular in the presence of corrosive products, such as petroleum products.

The coated part 26 is in particular a coated section of tube 7, the coating 30 being formed on the inside wall of this section of tube 7, and covering in particular the inside wall of the section of tube 7 over its entire surface, including the weld bead 12 when it exists.

The invention also relates to a method for manufacturing a coated part 26 as described above, comprising the supply of a substrate 28 made of the base material, followed by the application of a coating 30 on a surface of this substrate by a process of surfacing by welding by means of a filler wire having the composition described above.

In the case where the coated part 26 is a section of coated tube 7, the manufacturing method comprises in particular a step of manufacturing a section of tube 7 by implementing the method described above, followed by a step application of a coating 30 on an inner surface of this section of tube 7 by a process of hardfacing by welding by means of a filler wire having the composition described above.

The coating 30 improves the corrosion resistance of the tube section 7, for example during the transport of more or less corrosive petroleum products.

According to a particular embodiment, the tube 20 described above comprises two sections of tube 7 coated with a coating 30 as described above, linked together by a weld bead 22.

The invention also relates to a method of manufacturing a part 40 as shown schematically in Figure 6, made of an alloy as described above, comprising:

- the supply of a filler wire made from this alloy; and

- the manufacture of the part 40 by a metal additive manufacturing process using, as filler material, a filler wire made from the alloy as described above and/or a powder made from the alloy as described above.

The additive manufacturing process is for example an additive manufacturing process using an electric arc, a laser beam and/or an electron beam as an energy source to achieve the melting of the filler material.

The additive manufacturing process is in particular a Directed Energy Deposition additive manufacturing process. During this process, the filler material is deposited, in particular by a nozzle, and immediately fused by concentrated thermal energy, in particular a laser beam, an electron beam and/or an electric arc.

By way of example, the additive manufacturing process is an arc-wire, laser-wire, electron-beam-wire process (“Electron Beam Free Form Fabrication” or “Electron beam additive manufacturing”) or a hybrid additive manufacturing combining arc-wire and Laser-powder or arc-wire and Laser-wire technologies.

In the case where a hybrid additive manufacturing process combining arc-wire and Laser-powder or arc-wire and Laser-wire technologies is used, the powder and the filler wire are made in the alloy as described below. above.

The additive manufacturing processes mentioned above are known per se, and are therefore not described in detail.

In the case where the filler material comprises a powder, in particular within the framework of the hybrid arc-wire and laser-powder process, the process also comprises, prior to the manufacture of the part 40, a step of supplying a powder made from the alloy as described above. This powder, whose particle size after sieving is between 20 μm and 150 μm, is for example manufactured by atomization plasma from a wire made of an alloy as described above, the wire in particular having a diameter of approximately 3 mm.

The plasma atomization process is known per se, and is therefore not described in detail.

The invention also relates to a part 40 or part of a part made of an alloy as described above obtained by metal additive manufacturing.

This metal additive manufacturing process uses in particular, as filler material, a filler wire made from the alloy as described above and/or a powder made from the alloy as described above. .

A part or part of a part obtained by a metal additive manufacturing process, such as part 40, is raw from solidification. It therefore has a typical solidification microstructure of the nickel alloy considered, such a microstructure typically comprising columnar dendrites which grow by epitaxy on each other and whose orientation depends on the width and height of the metal wall fabricated . Furthermore, a part obtained by an additive manufacturing process has, due to its additive manufacturing process, a succession of superimposed solidification strata. Each stratum, obtained by solidification of deposited drops of molten metal, recasts the skin of the previous stratum in order to generate metallurgical continuity, and consequently heats the rest of the lower strata. The reheating temperature is lower the farther the stratum in question is from the zone undergoing melting and solidification. This particular microstructure is observable by metallographic observation on metallographic sections of the parts.

A part 40 or part of a part obtained by a metal additive manufacturing process can thus be distinguished from parts obtained by other processes, and in particular from a part obtained by conventional metallurgy which produces a recrystallized structure with homogeneous grains.

The parts 40 or parts of parts are intended in particular for the aeronautics, transport or energy market. They constitute, for example, casings, frames, tubes with complex shapes, valves, fixing lugs, or parts of parts having particular functions. By way of example, such a part of the part constitutes a heat exchanger element comprising, for example, channels for the circulation of a fluid formed by additive manufacturing on a support part, the support part being for example made of a different material that of the heat exchanger element.

Trials

In a first series of tests, the inventors carried out laboratory castings to obtain ingots of alloys having compositions as defined above, as well as comparative alloys, having compositions different from the composition described above. above.

These alloys were produced under vacuum, and the ingots thus obtained were hot transformed by rolling to obtain strips of dimensions 10x50x300 mm.

The alloy compositions of each of the bars tested are set out in Table 1 below.

The inventors then carried out the following tests on the bars thus obtained.

On some of these strips, they produced adjoining fusion lines, front and back, using a TIG torch in order to develop solidification structures in the thickness of the strip comparable to those obtained by TIG or MIG welding, in undiluted condition, and taken, from the molten zones, tensile and impact test specimens.

They then realized:

- mechanical tests by plane traction at ambient temperature (20°C) to measure the elastic limit at 0.2% elongation Rpo,2 at 20°C on the tensile specimens described above, in accordance with the NE standard EN ISO 6892-1 (December 2019). The results of these tests are summarized in the column entitled "Rpo,2" of Table 2 below.

- resilience tests at room temperature (20°C) on the resilience specimens described above with measurement of the impact fracture energy (denoted KCV), in accordance with standard NF EN ISO 148-1 (January 2011 ). The fracture energy is expressed in J/cm ² . It reflects the resilience of the piece. The results of these tests are summarized in the column entitled "KCV" of Table 2 below.

They also measured, in the molten zones of the bars, the surface fraction of phases precipitated during the solidification of the molten metal under the passage of the TIG torch. The surface fraction of precipitated phases is determined by image analysis on images of the largets obtained with a scanning electron microscope (SEM). Indeed, the precipitated phases correspond to the white areas on these images, and are detected by image processing software, which detects the white areas by means of a gray level analysis and then determines the surface fraction occupied by these white areas. The results of these measurements are summarized in the column entitled "Fs" of Table 2 below.

The inventors also carried out, on the strips not subjected to contiguous fusion lines, Varestraint tests according to the European standard FD CEN ISO/TR 17641 -3 (November 2005) under 3.2% plastic deformation in order to evaluate their resistance to hot cracking with measurement of the total length of cracks developed during the test. The results of these tests are summarized in the column headed "Lethal Cracks" in Table 2 below.

Finally, the inventors carried out potentiometric tests to test the resistance to localized corrosion of the alloys. To this end, they measured the pitting potential V in LiCI medium at 11.9 ^mol.l'1 at a pH of 5.4 and at a temperature of 30°C and compared this pitting potential with that of the Inconel ® 625 (Vi _ncO nei 625/SCE < 120 mV), where SCE is a reference potential with respect to the saturated calomel electrode.

In Tables 1 and 2 below, assays which are not according to the invention are underlined.

Table 1: Composition of the alloys of the first series of tests

In the alloys 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.

For all alloys in Table 1, the balance is nickel, plus impurities resulting from smelting.

Furthermore, all the compositions are indicated in percentage by weight.

Table 1

Furthermore, during potentiometric tests, alloys A1 to A28 in Table 1 developed a pitting potential V compared to the reference potential compared to the saturated calomel electrode greater than or equal to 150 mV. These alloys therefore have better resistance to localized corrosion than the Inconel ® 625 alloy.

As indicated above, the following properties are preferably sought, in combination: - an elastic limit Rpo,2 greater than or equal to 500 MPa;

- a KCV resilience greater than or equal to 100 J/cm ² ;

- a total length of cracks less than or equal to 20 mm;

- a surface fraction of precipitated phases Fs less than or equal to 1.5%;

- resistance to localized corrosion greater than or equal to that of the Inconel ® 625 alloy. Among these parameters, the total length of the cracks is representative of the weldability of the alloy. The total length of cracks for the Inconel ® 625 alloy being equal to 20 mm, a total length of cracks less than or equal to 20 mm corresponds to a weldability greater than or equal to the weldability of the Inconel ® 625 alloy, and is therefore satisfactory for the applications considered.

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 as described above.

On the contrary, the elastic limit Rpo,2 is less than or equal to 500 MPa in the case of the comparative examples A1, A7, A18, A24, 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. It is noted that, within the framework of these counter-examples, the relation - 0.5 x (Cr+Fe) + 25% S Mo+W S - 0.5 x (Cr+Fe) + 30% is not respected .

Moreover, as comparative examples A6, A13, A17, A23 and A28 show, the alloys comprising iron at a content greater than 1.0% exhibit degraded ductility, as well as increased sensitivity to hot cracking.

In general, the inventors have observed that a surface fraction of precipitated phases Fs greater than 1.5% results in a KCV resilience of less than 100 J/cm ² and/or a crack length greater than 20 mm.

The inventors also carried out a second series of tests, under the same conditions as mentioned with regard to the first series of tests, but with bars made from alloys having the compositions summarized in Table 3. Furthermore, the results tests carried out on these strips are shown in Table 4.

Table 3: Composition of the alloys of the second series of tests

In the alloys 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.

For all alloys in Table 3, the balance is nickel, plus impurities resulting from smelting.

Furthermore, all the compositions are indicated in percentage by weight.

Table 4: Results of the tests carried out on the bars made from the alloys of

Table 3

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

It can therefore be seen that the properties sought in terms of yield strength, resilience, weldability, surface fraction 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 composition as described above.

The other results confirm the conclusions drawn from Table 2.

In particular, the elastic limit Rpo,2 is less than or equal to 500 MPa in the case of comparative examples B1, B7, B18, B24, while the resilience KCV is insufficient in the case of comparative examples B5, B6, B12 , B13, B17, B22, B23, B27, B28. It is noted that, within the framework of these counter-examples, the relation - 0.5 x (Cr+Fe) + 25% S Mo+W < - 0.5 x (Cr+Fe) + 30% is not respected.

In addition, the weldability and the resilience are degraded in the case where the alloy contains iron at a content greater than 1.0%.

In addition, by comparing the results of Tables 2 and 4, it can be seen that the addition of rare earths therefore improves the hot cracking resistance of the alloy.

The addition of rare earths is particularly advantageous when the base metal to be welded has higher sulfur and/or oxygen contents than the filler wire. Indeed, the inventors have observed that the rare earths contribute to the deoxidation and/or to the desulfurization of the liquid bath during the welding operation, and thus to the improvement of the resistance to hot cracking.

The alloy according to the invention has a yield strength Rpo,2 greater than or equal to 500 MPa and a KCV resilience greater than or equal to 100 J/cm ² , which makes it possible to obtain an overmatching of the mechanical properties with respect to a base metal having a yield strength Rpo,2 of less than 500 MPa such as alloys X56, X 60, X65 and X70. Thus, the characteristics of the welds can be ignored for the dimensioning of the welded assemblies made in such alloys as base materials.

Furthermore, it presents:

- corrosion resistance greater than or equal to that of the comparative Inconel ® 625 alloy;

- a weldability greater than or equal to that of the comparative Inconel ® 625 alloy.

Given its good properties, the alloy according to the invention can also be used advantageously in the context of parts as described above.

Claims

CLAIMS 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% £ If £ 0.75%

0.01% £ Al £ 0.35%

0.01% £ Mn £ 0.35%

Ca£0.005%

Mg£0.005%

#£0.01%

0.001% C££0.05%

0.001% £N£0.05%

S£0.003%

P £ 0.005% optionally, 0.0010% £ rare earths £ 0.015%, the silicon content being less than or equal to 0.25% in the presence of rare earths at a content between 0.0010% and 0.015%, the remainder being nickel and unavoidable impurities resulting from the production, the nickel content being greater than or equal to 54%. Alloy according to Claim 1, in which the iron content is less than or equal to 0.5%. Alloy according to Claim 1 or 2, in which the rare earths are chosen from yttrium, cerium and lanthanum and mixtures of these elements. Alloy according to Claim 3, in which the rare earths are chosen from yttrium or a mixture of cerium and lanthanum. Coated part (26) comprising a substrate (28) made of a base material and a coating (30), made of an alloy according to any one of claims 1 to 4, the base material being a metallic material, preferably a carbon steel, and for example an X56, X60, X65, X70 steel. Coated part according to claim 5, the coated part (26) being a section of tube (7). Filler wire made from an alloy having a composition according to any one of Claims 1 to 4. Process for manufacturing a filler wire according to Claim 7, the process comprising the following steps:

- supply of a semi-finished product made of an alloy according to any one of claims 1 to 4;

- hot transformation of this semi-finished product to form an intermediate wire; and

- transformation of the intermediate wire into filler wire, of diameter smaller than that of the intermediate wire, said transformation comprising a drawing step. Welded assembly (1; 7; 20) comprising at least two part parts (3; 12; 7), each made of a basic material, the part parts (3; 12; 7) being linked together by a cord solder (5; 15; 22) obtained from the filler wire according to claim 7, the base material being chosen from an iron-nickel alloy of the Fe-9Ni type, a nickel-based alloy of the C- type 276, C-4 or 22 and a carbon steel, for example an X56, X60, X65 or X70 steel. Welded assembly according to claim 9, said welded assembly forming a section of tube (7) comprising a folded sheet in the form of a tube, the longitudinal edges (12) of which constitute the parts of parts (3) joined together by the weld bead (15). Welded assembly according to Claim 10, the tube section (7) being provided with a coating (30) made of the alloy according to any one of Claims 1 to 4, over at least one part, and preferably the entirety, of its inner surface. Welded assembly according to claim 9, said welded assembly forming a tube (20) comprising at least two tube sections (7), the tube sections (7) constituting the part parts (3), and the weld bead (22 ) extending along the circumference of the tube (20), the tube sections (7) preferably being tube sections (7) according to one of claims 10 or 11. Method of manufacturing a welded assembly (1; 7; 20) according to any one of Claims 9 to 12, comprising the welding together of the two parts of the parts (3; 12, 7) by means of the filler wire according to Claim 7, the welding being in particular arc welding. Method of manufacturing a welded assembly (7) according to claim 10 or 11, in which the welding step is a step of welding together the longitudinal edges (12) of the sheet (9), the welding preferably being a longitudinal butt weld. Method of manufacturing a welded assembly (20) according to claim 12, comprising, before the welding step, the following successive steps:

- supply of a first tube section (7) and a second tube section (7) each extending along a longitudinal axis (M), and made of the base material;

- positioning of the first and second tube sections (7) such that a longitudinal end (24) of the first tube section (7) is arranged opposite a longitudinal end (24) of the second tube section (7 ) along the longitudinal axis (M) of the first and second tube sections (7); and in which the step of welding is a step of welding together two longitudinal ends (24) facing the first and second pipe sections (7), the welding preferably being orbital butt welding.

16. Part or part of part made of an alloy according to any one of claims 1 to 4, said part or part of part being obtained by metal additive manufacturing.

17. A method of manufacturing a part or part of a part, comprising a step of manufacturing said part or part of a part by a metal additive manufacturing process using, as filler material, a wire of filler made from the alloy according to any one of claims 1 to 4 and/or a powder made from the alloy according to any one of claims 1 to 4.

18. Use of filler wire according to claim 7:

- as a welding filler wire for welding together two parts of parts made of a base material, the base material being an iron-nickel alloy of the Fe-9Ni type, a nickel-based alloy of the C-276 type , C-4 or 22, or a carbon steel, and for example an X56, X60, X65 or X70 steel; and or

- as a hardfacing wire for producing a coating on parts or parts of parts made of a base material, the base material being a metallic material, preferably a carbon steel, and for example an X56, X60, X65 or X70; and or

- as filler wire in a metal additive manufacturing process.

19. Metal powder made from an alloy according to any one of claims 1 to 4.

20. A method of manufacturing a metal powder according to claim 19, said method comprising a step of supplying a filler wire according to claim 7, as well as a step of plasma atomizing this filler wire to get the metal powder.