PIPE SECTION, PIPE ARRANGEMENT, MANUFACTURING METHOD FOR PIPE SECTION AND PIPE ARRANGEMENT AND USE OF A PIPE ARRANGEMENT

Description

[0001] The invention relates to a pipe section, a pipe arrangement, a manufacturing method for a pipe section and a pipe arrangement and a use of a pipe arrangement, see claims 1, 10, 11, 14 and 15.

[0002] Corrosion-resistant and / or abrasive wear-resistant media-carrying pipes are known in various embodiments in the prior art and are used in particular as water, gas or oil pipeline pipes and / or in the chemical industry.

[0003] Particularly in the oil and gas production industry, the demand for corrosion-resistant pipes is growing, as it is expected that the fluids to be extracted will have higher water content and higher concentrations of hydrogen sulfide (H2S) and carbon dioxide (CO2) in the future.

[0004] Furthermore, the trend is emerging that the fluids to be conveyed increasingly contain hard solids, which also means that special protection of the pipelines against abrasive wear is increasingly in the interest of pipeline operators.

[0005] Suitable pipes for such media are steel pipes with a suitable inner coating, an inner lining or an inner plating, or a separate inner pipe, which offer cost advantages over pipes made of high-alloy steels.

[0006] Steel pipes are known to have a plastic wear-resistant coating on their inner surface, which carries the medium, to protect against corrosion and / or abrasive wear. This is also referred to as organic corrosion protection, and liquid epoxy coatings or multi-layered plastic wear-resistant coatings are common. In the latter case, epoxy resin mixtures in powder form are usually applied to the inner surface of a heated pipe. While such organic coatings are relatively corrosion-resistant, their service life is limited when used with media containing hard solid particles, as the plastic wear-resistant coating is worn away relatively quickly by abrasive wear.

[0007] Furthermore, clad steel tubes are known which are provided with an internal cladding made of a corrosion-resistant and / or abrasion-resistant metallic material.

[0008] Internally clad steel tubes can be differentiated according to their different manufacturing methods into metallurgically clad steel tubes and hydromechanically clad steel tubes.

[0009] Metallurgically clad pipe sections are typically formed from a roll-clad or explosively clad pre-material and welded together to form a pipe section. The two metal layers are metallurgically bonded together by a diffusion bridge, hence the term metallurgically clad pipe sections. When selecting materials for metallurgically clad pipe sections, it is essential to ensure that the different materials are sufficiently metallurgically compatible to form a sufficiently strong diffusion bridge.

[0010] Hydromechanically clad pipe sections represent a well-known alternative to metallurgically clad pipe sections. These are manufactured using a hydraulic expansion process of an inner tube within a seamless or welded outer tube. This process is also known as hydroforming. The inner tube is inserted into a suitable outer tube and initially deformed elastically, then plastically, until it abuts the inner wall of the outer tube. This is followed by a further expansion of the inner and outer tubes by approximately 0.5% to 1%, with the outer tube held in place by an external die. In this way, the inner tube is subjected to compressive residual stress due to the typically greater elastic springback rate of the outer tube, causing the inner tube to be compressed into the outer tube. The material thicknesses can be tailored to meet the requirements for strength and corrosion protection.Regarding the material combination, it is important to note that the inner and outer pipes must be welded together at their ends before expansion to prevent moisture from penetrating the space between the pipes during the expansion process. After expansion, the ends of the inner and outer pipes are chamfered and then re-welded or clad to prevent moisture from entering the finished pipe section. A final chamfer can then be applied to the hydromechanically clad pipe section, and the pipe ends can be calibrated using mechanical tools to ensure compliance with required tolerances.

[0011] According to a further development known in the prior art, hydromechanically clad pipe sections can be provided with an adhesive between the inner pipe and the outer pipe.

[0012] In addition to a plastic wear-resistant layer and the internally clad steel tubes, an inner coating of corrosion-resistant and / or abrasion-resistant weldable metals can be bonded to the outer tube by a weld overlay. This process is time-consuming, heat input into the outer tube is unavoidable, and the materials of the outer tube and the welding filler material mix. The inner coating is applied in several adjacent weld beads, resulting in a relatively rough and uneven surface structure. Machining can be performed to reduce flow resistance.

[0013] WO 2020 / 221819 A1 discloses the preamble of claims 1 and 11.

[0014] The invention is based on the objective of providing an improvement or an alternative to the prior art.

[0015] According to a first aspect of the invention, the problem is solved by a pipe section, in particular a pipe section for conveying oil and / or gas, according to claim 1, and comprising: a substrate layer consisting of a metallic base material, wherein the substrate layer has a length, an inner diameter, an inner surface, an outer surface, and at least two pipe section ends, each with an end region and an intermediate region; in each end region of the inner surface of the substrate layer, a first coating consisting of a first metallic coating material, wherein the first coating is welded to the substrate layer, and wherein the first coating has a first thickness, a penetration depth, and a longitudinal extent; and in the intermediate region of the inner surface of the substrate layer, a second coating consisting of a second metallic coating material, wherein the second coating is sprayed onto the substrate layer by a thermal spraying process; wherein the carrier layer has a roughness R on the inner surface a exhibiting a roughness R greater than or equal to 0.2 µm a of greater than or equal to 0.4 µm and particularly preferably a roughness R a of greater than or equal to 0.8 µm.

[0016] The following terminology should be explained in this regard: First, it should be expressly pointed out that, within the scope of the present patent application, indefinite articles and numerical indications such as "one", "two", etc. are generally to be understood as "at least" indications, i.e., as "at least one...", "at least two...", etc., unless it is expressly evident from the respective context or it is obvious or technically necessary for the person skilled in the art that only "exactly one...", "exactly two...", etc., can be meant.

[0017] In the context of the present patent application, the term "in particular" is always to be understood as introducing an optional, preferred feature. The term is not to be understood as "namely" or "specifically".

[0018] A "pipe section" is understood to be an elongated hollow body which is designed to transport a designated fluid.

[0019] A pipe section can be designed to transport a designated fluid under corrosion-chemical stress caused by the fluid and / or under abrasive wear caused by entrained granular solids.

[0020] In particular, a pipe section may be designed for the transport of oil and / or gas and / or a fluid containing a liquid fossil energy carrier and / or for use in chemical plant construction.

[0021] A "support layer" is understood to be a layer of the pipe section made of a base material, which is designed to absorb and transmit external and / or internal loads.

[0022] The carrier layer can be a hollow body with thicker walls compared to the first and / or second coating. The carrier layer can be adjacent to the first and / or second coating on the outside.

[0023] The carrier layer can have a weld seam or be manufactured seamlessly.

[0024] The support layer can have an inner diameter of 150 mm or greater, preferably 250 mm or greater, more preferably 450 mm or greater, and most preferably 650 mm or greater. Furthermore, the inner diameter of the support layer is preferably 850 mm or greater, more preferably 1050 mm or greater, and most preferably 1250 mm or greater.

[0025] The support layer can have a wall thickness of 6 mm or more, preferably 8 mm or more, more preferably 10 mm or more, and particularly preferably 12 mm or more. Furthermore, the support layer can have a wall thickness of 15 mm or more, preferably 20 mm or more, more preferably 25 mm or more, and particularly preferably 30 mm or more. More preferably, the support layer can have a wall thickness of 35 mm or more, more preferably 40 mm or more, more preferably 45 mm or more, and particularly preferably 50 mm or more.

[0026] The support layer can have a length greater than or equal to 4 m, preferably a length greater than or equal to 8 m, more preferably a length greater than or equal to 12 m and particularly preferably a length greater than or equal to 13 m.

[0027] The support layer can be essentially circular in shape, although it may exhibit an ovality.

[0028] A "base material" of the substrate layer is defined as a steel iron-carbon alloy with a carbon mass fraction of no more than 2.1%. Preferably, the base material contains, in addition to its main component iron, primarily carbon as a minor component. In other words, the proportion of any single alloying element or the proportion of the total alloying elements can be less than the carbon content of the base material.

[0029] The base material can have a carbon content of less than or equal to 0.3%, preferably a carbon content of less than or equal to 0.26%, and particularly preferably a carbon content of less than or equal to 0.22%, which can improve the weldability of the base material.

[0030] The base material may contain manganese, which can improve its forgeability, weldability, strength, and wear resistance. Preferably, the base material has a manganese content of greater than or equal to 0.8%, more preferably a manganese content of greater than or equal to 1.2%, more preferably a manganese content of greater than or equal to 1.4%, and most preferably a manganese content of greater than or equal to 1.6%.

[0031] A silicon content in the base material can increase the tensile strength and yield strength. The base material can have a silicon content of greater than or equal to 0.35%, preferably a silicon content of greater than or equal to 0.4%, and particularly preferably a silicon content of greater than or equal to 0.45%.

[0032] The yield strength of the base material can be greater than or equal to 280 N / mm², preferably greater than or equal to 350 N / mm², more preferably greater than or equal to 350 N / mm², and particularly preferably greater than or equal to 410 N / mm². Furthermore, the yield strength of the base material is preferably greater than or equal to 440 N / mm², more preferably greater than or equal to 480 N / mm², and particularly preferably greater than or equal to 550 N / mm².

[0033] The base material can be a material conforming to the API (American Petroleum Institute) standard, in particular an X42, an X52, an X60, an X65, an X70, an X80, or a base material with a higher proportion of alloying elements. Furthermore, the metallic base material can be an L 360QB, an L 415QB, an L 450QB, or an L 485QB according to DIN EN 10208-2.

[0034] A pipe section has a "pipe section end" at each end of the elongated hollow body, to which an "end region" is attached. The end regions arranged on both sides extend longitudinally to the "intermediate region" of the pipe section, which is located essentially in the middle or centrally.

[0035] The end regions are determined by the "first coatings" made of a "first coating material" arranged on the inner surface of the carrier layer in the end regions on both sides.

[0036] The intermediate area has a "second coating" made of a "second coating material".

[0037] It is expressly pointed out that the designation "second coating" does not necessarily require a first coating. Consider, for example, an embodiment of a pipe section which has a coating on the inner surface of the substrate layer consisting of a metallic coating material of a certain thickness, wherein the coating is sprayed onto the substrate layer using a thermal spraying process. In this particularly preferred embodiment, the term "second coating" used below can be equated with the term "coating" within the scope of this description, without specifying a number.Similarly, within the scope of this description, this applies to the term "second metallic coating material", which can be equated with the term metallic coating material without specifying a number, and to the term "second thickness", which can be equated with the term thickness without specifying a number.

[0038] The length of the intermediate layer is at least greater than or equal to the length of the carrier layer minus the respective longitudinal extents of the end layers, ensuring a continuous coating. For this purpose, the second and first coatings can be arranged overlapping, at least partially, in an overlapping area, with the second coating overlapping the first.

[0039] The first and second coating materials can be identical, so that the material properties of the coating in a pipe assembly consisting of several pipe sections can be largely homogeneous along the length of the pipe assembly, especially with respect to a designated fluid in the pipe assembly. However, the first and second coating materials can also differ from each other, so that, particularly in the area of ​​a metallurgical bond, a desired alloy forms which in turn exhibits the necessary corrosion resistance and / or abrasion resistance properties.

[0040] In particular, the first coating and / or the second coating exhibits sufficient corrosion resistance to H2S and / or CO2, which is currently not achieved by a plastic coating.

[0041] The first coating is "welded" to the substrate, which refers to a material-bonded connection between the substrate and the first coating created using a weld overlay process. This results in a "penetration depth," characterized by a mixing of the substrate material and the first coating material, and limited to the area that was occupied by the substrate material before welding.

[0042] The "first thickness" of the first coating refers to the thickness of the first coating layer extending radially to the longitudinal direction of the pipe section. The first thickness thus also includes the penetration depth of the first coating.

[0043] A "thermal spraying process" is a surface coating method in which a spray material is liquefied inside or outside a spray torch, accelerated in a gas stream in the form of spray particles, and propelled onto the surface of the component to be coated. Advantageously, the component surface is not melted and is subjected to only minimal thermal stress. Layer formation occurs because the spray particles flatten to a greater or lesser degree upon impact with the component surface, depending on the process and material. They adhere primarily through mechanical interlocking and build up the spray coating in layers. Quality characteristics of spray coatings include low porosity, good adhesion to the component, freedom from cracking, and a homogeneous microstructure. Thermal spraying processes can be distinguished based on the energy source used to liquefy the spray material.The different processes include arc spraying, plasma spraying, flame spraying, cold gas spraying and laser spraying.

[0044] By using a first coating bonded to the carrier layer with a material bond and a second coating bonded to the carrier layer with a form-fit, it can advantageously be achieved that the coating is robust against the heat input during the designated welding of several pipe sections to form a pipe assembly and against any mechanical loads occurring at the pipe section ends, while also being cost-effective.

[0045] Roughness refers to the unevenness of a surface's height. Various calculation methods exist for the quantitative characterization of roughness, each taking into account different surface characteristics. The "roughness Ra" or average roughness indicates the average distance of a measurement point on the surface from the center line.

[0046] It is understood that when specifying roughness, the roughness of the substrate layer is understood to be that after roughening the inner surface of the substrate layer. The substrate layer exhibits this roughness on its inner surface.

[0047] If an initial coating has already been applied to the end region of the substrate, the roughness of the substrate in this end region can no longer be specified. In this case, the roughness specification can refer to the intermediate region of the inner surface of the substrate.

[0048] The first coating and the second coating work together to protect against corrosion and / or abrasive wear of the substrate.

[0049] Internally clad steel tubes are known in the prior art. The carrier layer of these internally clad steel tubes consists of a rolled pre-material. During cladding, especially metallurgical cladding, the surfaces to be joined must be metallically clean.

[0050] In contrast, a pipe section is hereby proposed comprising a coating of a metallic coating material applied to the inside of the carrier layer by a thermal spraying process, in particular a first coating welded to the metallic carrier layer consisting of a first metallic coating material and a second coating of a second metallic coating material applied to the carrier layer by a thermal spraying process, wherein the carrier layer has a minimum roughness Ra on the inside, in particular a roughness Ra of greater than or equal to 0.2 µm, preferably a roughness Ra of greater than or equal to 0.4 µm and particularly preferably a roughness Ra of greater than or equal to 0.8 µm.

[0051] The carrier layer advantageously has a roughness Ra of greater than or equal to 1.6 µm on its inner surface, preferably a roughness Ra of greater than or equal to 3.2 µm, more preferably a roughness Ra of greater than or equal to 5.0 µm, and most preferably a roughness Ra of greater than or equal to 5.6 µm. Furthermore, the carrier layer can have a roughness Ra of greater than or equal to 6.3 µm on its inner surface, more preferably a roughness Ra of greater than or equal to 7.1 µm, more preferably a roughness Ra of greater than or equal to 8.0 µm, and most preferably a roughness Ra of greater than or equal to 10.0 µm.

[0052] The substrate and the coating, in particular the second coating, are bonded together by a form-fit connection through the use of a thermal spraying process for applying the coating, especially the second coating. It has been shown that the roughness values ​​required here result in particularly good adhesion of the second coating to the substrate, thereby improving the delamination resistance of the coating, especially the second coating.

[0053] The required minimum roughness values ​​can be achieved in particular by means of a surface preparation process, especially by a blasting process, particularly using corundum or steel grit as the blasting medium. Table 1: Roughness, resistance to abrasive wear and delamination resistance with a second coating thickness of 200 µm; for other second thickness values ​​between 100 µm and 500 µm, the influence of the second thickness on the properties is negligible to a first approximation (rating between 0 and 10, where 0 represents the smallest possible value and 10 the largest possible value of the respective property.) roughness Resistance to abrasive wear Delamination resistance 0,2 µm 0 0 0,4 µm 0 0 0,8 µm 2 2 1,6 µm 5 5 3,2 µm 8 8 5,0 µm 10 10 5,6 µm 10 10 6,3 µm 10 10 7,1 µm 10 10 8,0 µm 9 10 10 µm 8 10 12,5 µm 7 10 25 µm 6 10

[0054] Therefore, a roughness of the carrier layer on the inner surface is required which is comparatively high compared to a rolled surface with a characteristic roughness Ra of less than or equal to 0.1 µm, thereby achieving a better form fit and / or better adhesion of the coating, especially the second coating, to the carrier layer.

[0055] According to the invention, the carrier layer has a roughness Ra of less than or equal to 25.0 µm on the inner surface, preferably a roughness Ra of less than or equal to 12.5 µm and particularly preferably a roughness Ra of less than or equal to 10.0 µm.

[0056] The carrier layer advantageously has a roughness Ra of less than or equal to 8.0 µm on its inner surface, preferably a roughness Ra of less than or equal to 7.1 µm, and particularly preferably a roughness Ra of less than or equal to 6.3 µm. Furthermore, the carrier layer can have a roughness Ra of less than or equal to 5.6 µm on its inner surface, preferably a roughness Ra of less than or equal to 5.0 µm, and particularly preferably a roughness Ra of less than or equal to 3.2 µm.

[0057] It has been shown that with increasing values ​​of the roughness of the inner surface of the carrier layer, in some embodiments a greater thickness of the coating, in particular a greater thickness of the second coating, may become necessary in order to achieve homogeneous and sufficiently durable properties of the coating, in particular of the second coating.

[0058] The maximum roughness values ​​Ra required here for the inner surface of the substrate layer allow the thickness of the coating, especially the thickness of the second coating, to be brought into a good compromise between adhesion of the coating, especially the second coating, to the substrate layer and cost of the coating, especially the second coating, for some applications.

[0059] According to a preferred embodiment, the coating has a thickness, in particular the second coating a second thickness, of less than or equal to 2,500 µm, preferably a second thickness of less than or equal to 750 µm and particularly preferably a second thickness of less than or equal to 500 µm.

[0060] The following terminology should be explained: The "thickness" of the coating, in particular the "second thickness of the second coating," refers to the thickness of the second coating layer extending radially to the longitudinal direction of the pipe section. The second thickness is assessed based on the average roughness of the inner surface of the substrate layer.

[0061] The thickness of the second coating can be less than the thickness of the first coating.

[0062] The second coating can have a second thickness of less than or equal to 1,500 µm, preferably a second thickness of less than or equal to 1,000 µm, more preferably a second thickness of less than or equal to 600 µm, and particularly preferably a second thickness of less than or equal to 400 µm. Furthermore, the second coating can have a second thickness of less than or equal to 300 µm, preferably a second thickness of less than or equal to 200 µm, more preferably a second thickness of less than or equal to 150 µm, and particularly preferably a second thickness of less than or equal to 100 µm.

[0063] Surprisingly, and contrary to the previous assumption that greater thickness of the second coating leads to a lower tendency for delamination, it was found that the opposite is true with further increases in thickness. Due to the thermal spraying process used to apply it, the second coating exhibits slight porosity. It has been shown that, in conjunction with a corrosion process within these pores, a greater thickness of the second coating can lead to reduced delamination resistance. Table 2: Second thickness, material costs, resistance to abrasive wear and delamination resistance (each rated between 0 and 10, where 0 represents the lowest possible value and 10 the highest possible value of the respective property.) Second thickness Material costs Resistance to abrasive wear Delamination resistance 100 µm 0,4 0,2 7 150 µm 0,6 0,5 9 200 µm 0,8 0,8 10 300 µm 1,2 1,2 10 400 µm 1,6 1,6 10 500 µm 2 2 10 600 µm 2,4 2,4 9 750 µm 3 3 9 1.000 µm 4 4 8 1.500 µm 6 6 7 2.500 µm 8 8 4 3.000 µm 10 10 2

[0064] Therefore, a second thickness of the second coating with a specified maximum thickness is proposed here.

[0065] At the same time, the effort required for a long-lasting, durable, and corrosion-resistant coating of a pipe section is significantly reduced. This is because there is no need for complex plating of the entire pipe section, and no recoating of the weld seam area on the inner surface is required after the individual pipe sections have been welded together.

[0066] The pipe section proposed here is particularly robust against corrosion and / or abrasion due to its first and second coatings, especially compared to currently known plastic coatings.

[0067] The comparatively thin material of the second coating can advantageously lead to savings in costly alloying elements.

[0068] Compared to the outer pipe of a hydromechanically clad pipe section, the roughness on the inner surface of the carrier layer can be greater, resulting in a better material bond between the carrier layer and the coating.

[0069] In comparison to metallurgically clad pipe sections, the material combination of the base material of the carrier layer and the first and / or second coating material is not dependent on the diffusion bond to be achieved during metallurgical cladding.

[0070] In contrast to a hydromechanically clad pipe section, the second coating material can be selected independently of its weldability to the base material. With hydromechanical cladding, the requirement for a tight weld joint between the substrate and the coating means that the entire coating material must be weldable in combination with the base material.

[0071] The largely free choice of the second coating material allows for better resistance to abrasion and / or better corrosion resistance and / or higher ductility of the second coating.

[0072] In contrast to a hydromechanically clad pipe section, the application of the first and / or second coating does not cause plastic deformation of the carrier layer, which reduces or eliminates the need for calibration of the pipe section ends.

[0073] In particular, the use of a comparatively thin coating compared to the hydromechanically clad pipe section, whose inner pipe has a thickness of greater than or equal to 3 mm due to the process, leads to a lower need for particularly expensive alloying elements and thus to an economic superiority over a hydromechanically clad pipe section, which in turn already has this advantage over a metallurgically clad pipe section due to the pre-material used and the manufacturing process.

[0074] In summary, the pipe section proposed here can achieve optimization for the highest demands in terms of strength and / or corrosion resistance and / or resistance to abrasive wear and / or cost-effectiveness. The carrier layer, consisting of the base material, fulfills the static and / or dynamic mechanical requirements, while the first and second coatings counteract corrosion and / or abrasive wear.

[0075] According to a particularly preferred embodiment, the second coating has a second thickness of greater than or equal to 100 µm, preferably a second thickness of greater than or equal to 200 µm and particularly preferably a second thickness of greater than or equal to 400 µm.

[0076] The second coating can have a second thickness of greater than or equal to 150 µm, preferably a second thickness of greater than or equal to 300 µm, more preferably a second thickness of greater than or equal to 500 µm, and particularly preferably a second thickness of greater than or equal to 600 µm. Furthermore, the second coating can have a second thickness of greater than or equal to 750 µm, preferably a second thickness of greater than or equal to 1,000 µm, more preferably a second thickness of greater than or equal to 1,500 µm, and particularly preferably a second thickness of greater than or equal to 2,500 µm.

[0077] The minimum values ​​required here for the second thickness ensure sufficient resistance to corrosion and abrasive wear, as well as sufficient delamination resistance of the second coating.

[0078] According to another advantageous embodiment, the carrier layer has a step on an inner edge.

[0079] Preferably, the longitudinal extent of the step can correspond to the longitudinal extent of the first coating.

[0080] A step can ensure that the support layer in the area of ​​the step no longer exhibits ovality on the inner surface, thus facilitating the designated joining of several pipe sections into a pipe assembly.

[0081] In some embodiments, it has proven advantageous for the thickness of the first coating to be greater than that of the second coating. The proposed transition section allows for a largely straight profile of the inner surface of the pipe section in the transition area between the first and second coatings, despite the different coating thicknesses. This advantageously reduces the designated flow resistance of the pipe section.

[0082] Preferably, the carrier layer and / or the first coating has a chamfer on an inner edge and / or an outer edge.

[0083] This facilitates the welding of multiple pipe sections into a pipe assembly. In particular, homogeneous weld seam surfaces with reduced or no weld reinforcement can be achieved, especially for the first coating. In this way, the properties of the first coating can be retained even after welding into a pipe assembly, resulting in advantageously low flow resistance in the area of ​​the previous pipe section ends.

[0084] Preferably, the first coating is applied to the substrate layer using a cladding welding process, in particular a laser cladding welding process.

[0085] The following definition should be explained: "Layered welding" refers to welding in which the filler material alone creates a volume build-up, usually in the form of a coating layer. It is therefore classified as a coating process.

[0086] For the initial coating, a conventional welding process is one of the options, in particular a classic wire fusion welding process, which advantageously allows for high layer thicknesses.

[0087] In laser cladding, a high-power laser serves as the heat source. This allows for a shallow penetration depth compared to other cladding processes.

[0088] The first coating preferably has a penetration depth of less than or equal to 500 µm, preferably a penetration depth of less than or equal to 150 µm and particularly preferably a penetration depth of less than or equal to 75 µm.

[0089] Furthermore, the first coating can have a penetration depth of less than or equal to 250 µm, preferably a penetration depth of less than or equal to 100 µm, more preferably a penetration depth of less than or equal to 40 µm and particularly preferably a penetration depth of less than or equal to 25 µm.

[0090] While the material properties of the base material remain unchanged, these properties are altered in the heat-affected zone required by the weld overlay process. This alteration is due to grain growth, phase transformations, precipitation processes at the grain boundaries, and hardening. Similarly, changes occur in the weld metal through crystallization (formation of a cast microstructure), dissolution of accompanying elements, precipitation processes, segregation, shrinkage, and the resulting residual stresses. The shallower the penetration depth, the smaller the heat-affected zone and, consequently, the lower the energy input into the base material of the substrate layer.

[0091] The welding filler material applied for the first coating also undergoes a more homogeneous microstructure with a lower iron content due to the reduced dilution with iron at smaller penetration depths, and the properties of the welding filler material are largely retained even after the build-up welding.

[0092] Therefore, a minimal penetration depth is advantageous.

[0093] Advantageously, the first coating has a first thickness of less than or equal to 2,500 µm, preferably a first thickness of less than or equal to 1,000 µm and particularly preferably a first thickness of less than or equal to 600 µm.

[0094] Furthermore, the first coating can have a first thickness of less than or equal to 5,000 µm, preferably a first thickness of less than or equal to 1,500 µm, more preferably a first thickness of less than or equal to 750 µm and particularly preferably a first thickness of less than or equal to 550 µm.

[0095] The values ​​required here for the initial thickness of the first coating enable an advantageously thin first coating, thereby reducing material costs for the first coating material and costs for applying the first coating.

[0096] Optionally, the first coating has a first thickness of greater than or equal to 500 µm, preferably a first thickness of greater than or equal to 600 µm and particularly preferably a first thickness of greater than or equal to 700 µm.

[0097] Optionally, the first coating has a first thickness of greater than or equal to 400 µm, preferably a first thickness of greater than or equal to 550 µm and particularly preferably a first thickness of greater than or equal to 650 µm.

[0098] When using multiple pipe sections for a pipe assembly, it is advantageous to join these pipe sections by welding the corresponding pipe section ends together to create a material bond. The substrate and the first coating consist of different materials, which are mixed together at least in a transition layer due to the process. Particularly on the inner surface of the first coating, it is advantageous for its properties if the first coating consists only, or at least predominantly, of the first coating material. When welding multiple pipe sections to form a pipe assembly, further mixing of the substrate and the first coating material can occur, which can adversely affect the properties of the first coating.

[0099] The values ​​required here for the first thickness of the first coating can make it possible for the inner surface of the first coating of a pipe section or pipe arrangement to consist only or at least predominantly of the first coating material.

[0100] According to a preferred embodiment, the first coating has a longitudinal extent of greater than or equal to 30 mm, preferably a longitudinal extent of greater than or equal to 50 mm and particularly preferably a longitudinal extent of greater than or equal to 65 mm.

[0101] Advantageously, the first coating can have a longitudinal extent of 15 mm or greater, preferably 20 mm or greater, more preferably 40 mm or greater, and particularly preferably 60 mm or greater. Furthermore, the first coating can advantageously have a longitudinal extent of 70 mm or greater, preferably 80 mm or greater, more preferably 90 mm or greater, and particularly preferably 100 mm or greater.

[0102] When several pipe sections are joined to form a pipe assembly, heat is introduced at the respective pipe section ends and in the corresponding end regions. This can negatively affect the properties of the second coating. The required values ​​for the longitudinal extent of the first coating can reduce the heat input into the second coating from welding several pipe sections together to such an extent that the properties of the second coating are no longer affected, or at least no longer significantly affected.

[0103] According to a preferred embodiment, the first coating has a first thickness that varies with the circumferential angle of the pipe section.

[0104] The thickness of the first layer can vary, particularly with regard to the circumferential angle in the pipe section. This allows any ovality of the carrier layer to be reduced by varying the thickness of the first coating.

[0105] This can simplify the manufacture of a pipe arrangement according to the fourth aspect of the invention and / or reduce the flow resistance acting on a fluid flowing through the pipe arrangement.

[0106] The second coating is particularly preferred when sprayed onto the substrate using an arc spraying process.

[0107] The following terminology should be explained: "Arc spraying" refers to a wire spraying process in which electrically conductive materials are sprayed to create a coating. An electric arc is ignited between two wire-shaped spraying materials of the same or different types. The wire tips are melted at a temperature of up to approximately 4000 °C and blown onto the workpiece surface using an atomizing gas. Using nitrogen or argon instead of air as the atomizing gas can advantageously reduce material oxidation.

[0108] By using the arc spraying process, the deposition rate of the second coating can be advantageously increased. Furthermore, any electrically conductive wire alloy can be used to advantage as a coating material. A very thin second coating thickness of 50 µm or greater can be achieved with particular benefit. According to tests conducted, the second coating produced by arc spraying is especially robust and reliable.

[0109] By using the arc spraying process, a variable second coating thickness can be achieved, allowing for adaptation to local requirements. This can be particularly advantageous at the transition between the first and second coatings, ensuring a robust layer transition and / or minimal flow resistance, as the second coating applied by arc spraying at least partially overlaps the first. Furthermore, a variable coating thickness can contribute to reducing the internal ovality of the pipe section.

[0110] Advantageously, a metallic coating can be applied using the arc spraying process, which has advantageous hardness, abrasion resistance and cold impact resistance.

[0111] Preferably, the first coating and / or the second coating has a nickel content of greater than or equal to 38 wt.%, more preferably a nickel content of greater than or equal to 48 wt.% and particularly preferably a nickel content of greater than or equal to 58 wt.%, and / or a nickel content of less than or equal to 75 wt.%, more preferably a nickel content of less than or equal to 70 wt.% and particularly preferably a nickel content of less than or equal to 65 wt.%.

[0112] The nickel content makes it possible to achieve high corrosion resistance and / or high hardness and / or high toughness and / or high ductility in the first coating and / or the second coating.

[0113] A first coating material and / or second coating material may be, among others, Inconel Alloy 625 (also known as AISI Alloy 625, UNS N06625, NiCr22Mo9Nb and / or EN 2.4856), Inconel Alloy 825, Inconel Alloy 59, Inconel Alloy 926 and / or Inconel Alloy 367.

[0114] Inconel Alloy 625 is a nickel-based alloy characterized by high strength and resistance to high temperatures. It also exhibits remarkable protection against corrosion, even in strongly acidic environments, and oxidation. Furthermore, the alloy displays very good creep resistance and weldability.

[0115] Specifically, the substrate material can be a material conforming to the API (American Petroleum Institute) standard, in particular an X42, an X52, an X60, an X65, an X70, an X80, or a substrate material with a higher proportion of alloying elements. Furthermore, the metallic substrate material conforming to DIN EN 10208-2 can be an L 360QB, an L 415QB, an L 450QB, or an L 485QB, where this substrate material is coated with a first and / or a second coating of Alloy 625. In other words, consider a substrate made of an X42 or a substrate material from the above list with a higher yield strength than X42, coated with a first and / or a second coating of Alloy 625.

[0116] Preferably, the first coating and / or the second coating has a chromium content of greater than or equal to 12 wt.%, more preferably a chromium content of greater than or equal to 16 wt.% and particularly preferably a chromium content of greater than or equal to 20 wt.%, and / or a chromium content of less than or equal to 31 wt.%, more preferably a chromium content of less than or equal to 27 wt.% and particularly preferably a chromium content of less than or equal to 23 wt.%.

[0117] The chromium content allows the first coating and / or the second coating to exhibit particularly strong corrosion resistance and / or particularly good heat resistance.

[0118] Furthermore, the first coating and / or the second coating preferably has a molybdenum content of greater than or equal to 2 wt.%, preferably a molybdenum content of greater than or equal to 5 wt.% and particularly preferably a molybdenum content of greater than or equal to 8 wt.%, and / or a molybdenum content of less than or equal to 17 wt.%, preferably a molybdenum content of less than or equal to 13 wt.% and particularly preferably a molybdenum content of less than or equal to 10 wt.%.

[0119] The proposed molybdenum content improves the acid resistance and thus the corrosion resistance of the first and / or second coating. Furthermore, the proposed molybdenum content increases the hardness and strength of the first and / or second coating, thereby enhancing their resistance to abrasive wear. Additionally, the molybdenum content can prevent or reduce temper embrittlement of the first and / or second coating.

[0120] In other words, the molybdenum content can improve the strength, corrosion resistance and heat resistance of the first coating and / or the second coating.

[0121] Optionally, the first coating and / or the second coating has a proportion of niobium in combination with tantalum of greater than or equal to 2 wt.%, preferably a proportion of niobium in combination with tantalum of greater than or equal to 2.6 wt.% and particularly preferably a proportion of niobium in combination with tantalum of greater than or equal to 3.15 wt.%, and / or a proportion of niobium in combination with tantalum of less than or equal to 6 wt.%, preferably a proportion of niobium in combination with tantalum of less than or equal to 5 wt.% and particularly preferably a proportion of niobium in combination with tantalum of less than or equal to 4.15 wt.%.

[0122] The presence of niobium can advantageously improve the weldability of the first and / or second coating. Due to the similarity of niobium and tantalum, niobium ores predominantly also contain tantalum; therefore, it is advantageous not to separate the tantalum from the niobium and to add a combination of niobium and tantalum as alloying elements to the first and / or second coating.

[0123] Particularly preferably, the first coating and / or the second coating has a Vickers hardness, measured at 20°C, of ​​greater than or equal to 150 HV, more preferably a Vickers hardness of greater than or equal to 200 HV and more preferably a Vickers hardness of greater than or equal to 250 HV.

[0124] "Hardness" refers to the mechanical resistance that the first and / or second coating offers to the mechanical penetration of another body. Vickers hardness corresponds to the hardness test named after the Vickers company, which, due to the flat shape of the test specimen, is particularly suitable for thin-walled coatings.

[0125] By selecting a coating material with a hardness greater than or equal to the value required here, the resistance to abrasive wear can be increased in particular.

[0126] Furthermore, the first coating and / or the second coating preferably has an elongation at break A, measured at 20°C, of ​​greater than or equal to 25%, preferably an elongation at break A of greater than or equal to 30% and particularly preferably an elongation at break A of greater than or equal to 35%.

[0127] The following definition should be explained: The "elongation at break A" is a characteristic value in materials science that indicates the permanent elongation of the tensile specimen after fracture, relative to the initial gauge length, following uniaxial mechanical stress. The higher the elongation at break value of a material, the higher its ductility or deformability.

[0128] If the yield strength of a material is exceeded, irreversible changes occur in its crystal lattice. If the stress on the material is removed, the component returns to its original shape, leaving behind a degree of plastic deformation.

[0129] Ductile materials have the advantage that plastic strains, up to a certain limit, do not lead to brittle fracture of the workpiece made from the material. However, if plastic strains occur during the workpiece's life cycle, in this case, the pipe section, it should be ensured that the workpiece is not stretched so much that its function can no longer be guaranteed.

[0130] In some applications of the pipe sections proposed here, these are first joined together to form a pipe assembly, which is then coiled for transport and uncoiled again afterward. This coiling process requires that the materials used for the carrier layer, the first coating, and the second coating can be plastically deformed non-destructively with the carrier layer. In other words, the carrier layer, the first coating, and the second coating need sufficient ductility to prevent brittle fractures and / or to prevent or at least sufficiently reduce delamination of the coating at locally plastically deformed areas.

[0131] In particular, for the second coating material, it has been shown under application conditions that the required ductility can counteract any delamination of the second coating material, even if the pipe section as a whole is not plastically deformed.

[0132] According to a preferred embodiment, the first coating and / or the second coating has a yield strength R p0,2, measured at 20°C, of ​​greater than or equal to 280 N / mm 2<, preferably a yield strength R p0,2 of greater than or equal to 300 N / mm 2< and particularly preferably a yield strength R p0,2 of greater than or equal to 320 N / mm 2< .

[0133] The following definition applies: The "yield strength Rp0.2" is understood to be the uniaxial mechanical stress at which the residual plastic strain after unloading, relative to the initial length of the specimen, is 0.2%. The yield strength Rp0.2 is therefore a strength characteristic for a material, in particular the first coating and / or the second coating.

[0134] The required values ​​for the yield strength R p0.2 allow the first coating and / or the second coating to be particularly advantageously adapted to the material behavior of the substrate.

[0135] If the substrate undergoes elastic and / or plastic deformation, this deformation also affects the first and / or second coating. If the yield strength Rp0.2 of the substrate and the first and / or second coating differs too much, especially if the yield strength Rp0.2 is too low and the yield strength Rp0.2 is too high for the first and / or second coating material, this can lead to residual stresses in the substrate and / or the first and / or second coating, which can cause delamination of the second coating.

[0136] If the yield strength Rp0,2 for the first and / or second coating material is lower than the yield strength of the substrate, the substrate may deform in the purely elastic range, while the first and / or second coating already undergo plastic deformation. If the external load on the pipe section is removed, residual stresses may occur, particularly in the contact layer between the substrate and the first and / or second coating.

[0137] If the yield strength R p0,2 for the first and / or second coating material is higher than the yield strength of the substrate, it can happen that the substrate deforms plastically, while the first coating and / or the second coating undergo purely elastic deformation, which can also cause residual stresses in a contact layer of the substrate and the first coating and / or second coating.

[0138] The required values ​​for the yield strength R p0,2 can prevent or at least reduce the formation of residual stresses in a contact layer between the carrier layer and the first coating and / or second coating as a result of deformation of the pipe section.

[0139] Advantageously, the first coating and / or the second coating has a tensile strength Rm, measured at 20°C, of ​​greater than or equal to 650 N / mm², preferably a tensile strength Rm of greater than or equal to 685 N / mm² and particularly preferably a tensile strength Rm of greater than or equal to 720 N / mm².

[0140] The following definition should be explained: The term "tensile strength R m" refers to the maximum uniaxial mechanical stress that the material can withstand until failure.

[0141] The tensile strength values ​​R m of the first and / or second coating material required here can prevent or at least greatly reduce the formation of cracks in the first coating and / or second coating under normal operating conditions and / or during winding and / or unwinding of a pipe assembly.

[0142] According to a preferred embodiment, the first coating and / or the second coating has a sealant.

[0143] The following terminology should be explained in this context: Coatings, especially those produced using a thermal spraying process, can exhibit porosity. This means that a coating may have openings on its surface that communicate with capillary spaces within the coating. As a result, a designated fluid within the pipe section can penetrate these capillary spaces, potentially leading to corrosion and / or abrasive wear. "Sealing" refers to at least partially filling these openings in the surface of the first and / or second coatings, as well as the communicating capillary spaces.

[0144] The sealing method proposed here allows openings and the capillary spaces communicating with them in the surface of the first and / or second coating to be advantageously at least partially filled, so that after sealing, the penetration of a designated fluid into the capillary space in the pipe section can be prevented or at least reduced. In this way, the corrosion protection of the first and / or second coating can be improved.

[0145] The sealant can optionally be polymer-based.

[0146] A "polymer-based sealant" is understood to be a sealant made of a material consisting of macromolecules.

[0147] This allows for a seal with an advantageously low viscosity of the sealing material at the time of processing and with an advantageously high viscosity after processing, so that the sealing material can advantageously penetrate into small openings and capillary spaces on the one hand and can be cured into a particularly hard and robust structure after penetration on the other.

[0148] According to a second aspect of the invention, the problem is solved by a pipe arrangement consisting of at least two pipe sections according to the first aspect of the invention, wherein a first pipe section and a second pipe section are connected to each other in a materially bonded manner at two corresponding pipe section ends.

[0149] A common use of one or more pipe sections according to the first aspect of the invention is to use them as a pipe assembly for conveying oil and / or gas and / or a liquid fossil fuel. For this purpose, it is advantageous to connect a plurality of pipe sections to form a pipe assembly, in particular two pipe sections, three pipe sections, four pipe sections, five pipe sections or more than five pipe sections.

[0150] Regarding the connection of the pipe sections, it is particularly advantageous to join them together using a material-bonded connection, which results in an extremely robust connection, even against seismic events.

[0151] The material-bonded connection can be designed such that the pipe assembly has a continuous coating on the inside with corrosion-resistant and / or abrasive wear-protective properties, in particular through a continuous combination of alternating first and second coatings. Preferably, the first coatings of adjacent pipe sections are welded together in such a material-bonded manner that the weld area has no or only a slight material difference to the adjacent material of the first coatings.

[0152] It is understood that the advantages of a pipe section according to the first aspect of the invention, as described above, extend directly to a pipe arrangement comprising a first pipe section and at least a second pipe section, each according to the first aspect of the invention.

[0153] It should be expressly noted that the subject matter of the second aspect can be advantageously combined with the subject matter of the preceding aspect of the invention, either individually or cumulatively in any combination.

[0154] According to a third aspect of the invention, the problem is solved by a method for producing a pipe section according to the first aspect of the invention, according to claim 11, comprising the following steps: Providing a substrate layer consisting of a metallic base material, wherein the substrate layer has a length, an inner diameter, an inner surface, an outer surface, and at least two pipe section ends, each with an end region and an intermediate region; roughening the substrate layer on the inner surface; applying a first coating in each end region of the inner surface of the substrate layer, in particular using a laser cladding process; and applying a second coating in the intermediate region of the inner surface of the substrate layer, in particular using an arc spraying process.

[0155] The substrate layer is roughened beforehand, at least in the area of ​​the inner surface that will later be coated, particularly the second coating. An abrasive material with an average grain size and a predetermined blasting pressure (within certain limits) can be used for this purpose. The abrasive material can consist of grit and / or corundum and / or precious corundum and / or zirconia alumina and / or flint and / or quartz and / or garnet and / or diamond and / or silicon carbide and / or chromium oxide and / or boron nitride.

[0156] Roughening the inner surface can improve the adhesion between the substrate and the coating, especially the second coating.

[0157] Before applying the coating, especially the first coating, the substrate layer can be provided with a step, particularly in the area of ​​the inner surface where the coating, especially the first coating, is to be applied.

[0158] The coating, particularly the first coating, can be applied with a varying thickness, especially the initial thickness, particularly depending on the circumferential angle of the pipe section. This can advantageously reduce the ovality of the pipe section, thus preventing or reducing the effort required for calibration of the pipe section end.

[0159] The first coating can be reworked after it has been applied, in particular using a machining process and / or a smoothing process.

[0160] When applying the coating, especially the second coating, it can be applied not only in the intermediate area but also at least partially overlapping the first coating.

[0161] After the coating, especially the second coating, has been applied, the coating, especially the first coating and / or the second coating, can be sealed.

[0162] After the coating, particularly the first coating, has been applied, the pipe section ends can be reworked. Preferably, the pipe section ends can be reworked flat using a machining process, so that they have a completely flat surface. The pipe section can also be chamfered, in particular on the outer edge and / or the inner edge. Furthermore, or additionally, the pipe section ends can be finished using a smoothing process.

[0163] The pipe section can be calibrated after the application of the coating, especially the first coating, so that the ovality of a pipe section end is within required tolerances after calibration.

[0164] It is understood that the advantages of a pipe section according to the first aspect of the invention, as described above, extend directly to a method for producing a pipe section according to the first aspect of the invention.

[0165] Optionally, the carrier layer on the inner surface is preheated to a temperature greater than or equal to 20°C before the application of the first coating and / or the second coating, preferably to a temperature greater than or equal to 40°C and particularly preferably to a temperature greater than or equal to 70°C.

[0166] Optionally, the carrier layer on the inner surface is preheated to a temperature greater than or equal to 50°C before the application of the first coating and / or the second coating, preferably to a temperature greater than or equal to 60°C and particularly preferably to a temperature greater than or equal to 80°C.

[0167] Such preheating allows the substrate layer to outgas before the second coating is applied, thereby improving the adhesion of the second coating to the substrate layer and achieving a flawless surface for the second coating.

[0168] It should be expressly noted that the subject matter of the third aspect can be advantageously combined with the subject matter of the preceding aspects of the invention, either individually or cumulatively in any combination.

[0169] Particularly preferably, a coating thickness, in particular a second thickness of a second coating, is applied with varying degrees of circumferential angle of the pipe section and / or longitudinal extent of the pipe section, in particular with a variance of greater than or equal to 3% with respect to the maximum thickness, in particular the second thickness, preferably with a variance of greater than or equal to 5% with respect to the maximum thickness, in particular the second thickness, and particularly preferably with a variance of greater than or equal to 10% with respect to the maximum thickness, in particular the second thickness.

[0170] In other words, it is proposed here to vary the thickness of the coating, in particular the thickness of the second coating, in certain areas, especially depending on the circumferential angle and / or the longitudinal extent of the coating, in particular the second coating.

[0171] This allows the coating, especially the second coating, to be particularly advantageously adapted to the expected operating conditions of the pipe section. Thus, the thickness of the coating, especially the thickness of the second coating, can be adjusted to local corrosion and / or abrasion conditions.

[0172] This aspect can also extend analogously to the initial thickness of the first coating, which can be applied in varying degrees depending on the circumferential angle and / or the longitudinal extent of the first coating.

[0173] This allows a pipe section to be adapted to the expected operating conditions as required, thereby saving material and costs for the coating, especially the first coating and / or the second coating, particularly in comparison to metallurgically clad pipes or hydromechanically clad pipes.

[0174] According to another aspect of the invention, the problem is solved by producing a pipe section using a method according to the third aspect of the invention.

[0175] It is understood that the advantages of a method according to the third aspect of the invention, as described above, extend directly to a pipe section produced using a method according to the third aspect of the invention.

[0176] According to a fourth aspect of the invention, the problem is solved by a method for producing a pipe arrangement from at least two pipe sections according to the second aspect of the invention, wherein a first pipe section and a second pipe section are joined together by material bonding at two corresponding pipe section ends.

[0177] It is understood that the advantages of a pipe arrangement according to the second aspect of the invention, as described above, extend directly to a method for manufacturing a pipe arrangement according to the second aspect of the invention.

[0178] It should be expressly noted that the subject matter of the fourth aspect can be advantageously combined with the subject matter of the preceding aspects of the invention, either individually or cumulatively in any combination.

[0179] According to a fifth aspect of the invention, the problem (see claim 15) is solved by using a pipe arrangement according to the second aspect of the invention for conveying an oil-containing and / or gas-containing fluid and / or a fluid comprising a liquid fossil energy carrier.

[0180] It is understood that the advantages of a pipe arrangement according to the second aspect of the invention, as described above, extend directly to a use of a pipe arrangement according to the second aspect of the invention.

[0181] Further advantages and features of the invention will become apparent from the exemplary embodiments described below. These will show in detail: Figure 1: schematically a first embodiment of a pipe section, wherein the pipe section is shown in a half-section; and Figure 2: schematically a second embodiment of a pipe section, wherein the pipe section is shown in a half-section and wherein only the support layer is shown to the right of the fracture line.

[0182] In the following description, identical reference numerals denote identical components or identical features, so that a description of a component in relation to one figure also applies to the other figures, thus avoiding repetitive descriptions. Furthermore, individual features described in connection with one embodiment can also be used separately in other embodiments.

[0183] The first embodiment of a pipe section 100 in Figure 1 , in particular a pipe section 100 for conveying oil and / or gas, consists essentially of: a carrier layer 110 made of a metallic base material 111, wherein the carrier layer 110 has a length 112, an inner diameter 113, an inner surface 114, an outer surface 115, and at least two pipe section ends 116, each with an end region 117 and an intermediate region 118; a first coating 120 made of a first metallic coating material 121 in each end region 117 of the inner surface 114 of the carrier layer 110, wherein the first coating 120 is welded to the carrier layer 110, and wherein the first coating 120 has a first thickness 122, a penetration depth 123, and a longitudinal extent 124; and a second coating 130 consisting of a second metallic coating material 131 in the intermediate area 118 of the inner surface 114 of the carrier layer 110, wherein the second coating 130 is sprayed onto the carrier layer 110 using a thermal spraying process.

[0184] The carrier layer 110 has a roughness Ra of greater than or equal to 0.2 µm on the inner surface 114, preferably a roughness Ra of greater than or equal to 0.4 µm and particularly preferably a roughness Ra of greater than or equal to 0.8 µm.

[0185] This roughness on the inner surface 114 was produced by a blasting process, in particular by a blasting process using corundum as the blasting medium.

[0186] The second coating 130 has a second thickness 132 of less than or equal to 2,500 µm, preferably a second thickness 132 of less than or equal to 750 µm and particularly preferably a second thickness 132 of less than or equal to 500 µm.

[0187] Advantageously, the second coating 130 can have a second thickness 132 of greater than or equal to 100 µm, preferably a second thickness 132 of greater than or equal to 200 µm and particularly preferably a second thickness 132 of greater than or equal to 400 µm.

[0188] The first coating 120 can be applied to the substrate 110 by a cladding welding process, in particular by a laser cladding welding process. The penetration depth 123 of the first coating 120 can be less than or equal to 500 µm, preferably less than or equal to 150 µm, and particularly preferably less than or equal to 75 µm.

[0189] The first coating 120 can have a first thickness 122 of less than or equal to 2,500 µm, preferably a first thickness 122 of less than or equal to 1,000 µm and particularly preferably a first thickness 122 of less than or equal to 600 µm.

[0190] The first coating 120 can have a longitudinal extent 124 of greater than or equal to 30 mm, preferably a longitudinal extent 124 of greater than or equal to 50 mm and particularly preferably a longitudinal extent 124 of greater than or equal to 65 mm.

[0191] The first coating 120 and / or the second coating 130 may have a sealant.

[0192] Pipe section 100 can have a chamfer 144.

[0193] The second embodiment of a pipe section 100 in Figure 2 resembles the first embodiment in Figure 1 , wherein the carrier layer 110 additionally has a step 142. This advantageously ensures that the first coating 120 and the second coating 130, despite their different first thickness 122 and second thickness 132, exhibit a largely straight course of the inner surface (not designated) of the pipe section 100 in the area of ​​the transition (not designated) and / or the overlap 119 from the first coating 120 to the second coating 130. Reference symbol list

[0194] 100 Pipe section 110 Carrier layer 111 Base material 112 Length 113 Inner diameter 114 Inner surface 115 Outer surface 116 Pipe section end 117 End area 118 Intermediate area 119 Overlap 120 First coating 121 First coating material 122 First thickness 123 Penetration depth 124 Longitudinal extent 130 Second coating 131 Second coating material 132 Second thickness 140 Inner edge 142 Step 144 Chamfer

Claims

1. A pipe section (100), in particular pipe section (100) for conveying oil and / or gas, comprising: - a support layer (110) consisting of a metal base material (111), the support layer (110) having a length (112), an inner diameter (113), an inner surface (114), an outer surface (115), at least two pipe section ends (116) each having an end region (117), and an intermediate region (118); - in each end region (117) of the inner surface (114) of the support layer (110), a first coating (120) consisting of a first metal coating material (121), the first coating (120) being welded to the support layer (110), the first coating (120) having a first thickness (122), a penetration depth (123) and a longitudinal extension (124); and characterized in that: - in the intermediate region (118) of the inner surface (114) of the support layer (110), a second coating (130) consisting of a second metal coating material (131), the second coating (130) being sprayed onto the support layer (110) using a thermal spraying process; wherein the support layer (110), on the inner surface (114), has a roughness Ra of more than or equal to 0.2 µm, preferably a roughness Ra of more than or equal to 0.4 µm, and more preferably a roughness Ra of more than or equal to 0.8 µm, and wherein the support layer (110), on the inner surface (114), has a roughness Ra of less than or equal to 25.0 µm.

2. The pipe section (100) according to claim 1, characterized in that the support layer (110), on the inner surface (114), has a roughness Ra of less than or equal to 12.5 µm, and more preferably has a roughness Ra of less than or equal to 10.0 µm.

3. The pipe section (100) according to any of claims 1 or 2, characterized in that the first coating (120) is applied to the support layer (110) using a deposition welding process, in particular using a laser deposition welding process.

4. The pipe section (100) according to claim 3, characterized in that the first coating (120) has a penetration depth (123) of less than or equal to 500 µm, preferably a penetration depth (123) of less than or equal to 150 µm, and more preferably a penetration depth (123) of less than or equal to 75 µm.

5. The pipe section (100) according to any of the preceding claims, characterized in that the second coating (130) is sprayed onto the support layer (110) using an arc spraying process.

6. The pipe section (100) according to any of the preceding claims, characterized in that the first coating (120) and / or the second coating (130) has a nickel content of greater than or equal to 38 wt.%, preferably a nickel content of greater than or equal to 48 wt.%, and more preferably a nickel content of greater than or equal to 58 wt.%, and / or a nickel content of less than or equal to 75 wt.%, preferably a nickel content of less than or equal to 70 wt.%, and more preferably a nickel content of less than or equal to 65 wt.%.

7. The pipe section (100) according to any of the preceding claims, characterized in that the first coating (120) and / or the second coating (130) has a chromium content of greater than or equal to 12 wt.%, preferably a chromium content of greater than or equal to 16 wt.%, and more preferably a chromium content of greater than or equal to 20 wt.%, and / or a chromium content of less than or equal to 31 wt.%, preferably a chromium content of less than or equal to 27 wt.%, and more preferably a chromium content of less than or equal to 23 wt.%.

8. The pipe section (100) according to any of the preceding claims, characterized in that the first coating (120) and / or the second coating (130) has a Vickers hardness, measured at 20°C, of greater than or equal to 150 HV, preferably a Vickers hardness of greater than or equal to 200 HV, and more preferably a Vickers hardness of greater than or equal to 250 HV.

9. The pipe section (100) according to any of the preceding claims, characterized in that the first coating (120) and / or the second coating (130) has a sealing.

10. A pipe assembly comprising at least two pipe sections (100) according to any of claims 1 to 9, wherein a first pipe section (100) and a second pipe section (100) are connected to one another at two corresponding pipe section ends (116) in a materially bonded manner.

11. A method for manufacturing a pipe section (100) according to any of claims 1 to 9, characterized by the following steps: - providing a support layer (110) consisting of a metal base material, the support layer (110) having a length (112), an inner diameter (113), an inner surface (114), an outer surface (115), at least two pipe section ends (116) each having an end region (117), and an intermediate region (118); - roughening the support layer (110) on the inner surface (114); - applying a first coating (120) in each end region (117) of the inner surface (114) of the support layer (110), in particular using a laser deposition welding process; and - applying a second coating (130) in the intermediate region (118) of the inner surface (114) of the support layer (110), in particular using an arc spraying process.

12. The method according to claim 11, characterized in that, before the first coating (120) and / or the second coating (130) is applied, the support layer (110) on the inner surface (114) is preheated to a temperature of greater than or equal to 20°C, preferably to a temperature of greater than or equal to 40°C, and more preferably to a temperature of greater than or equal to 70°C.

13. The method according to any of claims 11 to 12, characterized in that a second thickness (132) of the second coating (130) is applied in a varying manner depending on a circumferential angle of the pipe section (100) and / or a longitudinal extension of the pipe section (100), in particular with a variance of greater than or equal to 3% relative to the maximum second thickness (132), preferably with a variance of greater than or equal to 5% relative to the maximum second thickness (132), and more preferably with a variance of greater than or equal to 10% relative to the maximum second thickness (132).

14. The method for manufacturing a pipe assembly according to claim 10 from at least two pipe sections (100) according to any of claims 1 to 9, characterized in that a first pipe section (100) and a second pipe section (100) are connected to one another at two corresponding pipe section ends (116) in a materially bonded manner.

15. A use of a pipe assembly according to claim 10 for conveying an oil-containing and / or gas-containing fluid and / or a fluid comprising a liquid fossil energy carrier.