Impeller for a flow machine and method for producing an impeller

Abstract

The invention relates to a method (100) for producing an impeller (10) of a flow machine, comprising a main body (11) and at least one impeller blade (12), wherein the main body (11) and the impeller blade (12) are connected in an integrally bonded manner and wherein at least the following steps, preferably in the specified sequence, are carried out: a) processing (101) a blank (1) made of solid material in order to generate a first portion (11.1) of the main body (11); b) applying (102) at least one material layer (13) on the first portion (11.1) of the main body (11) in order to generate, at least in sections, a second portion (11.2) of the main body (11) through the use of an additive manufacturing process; c) applying (103) at least one material layer (13) on the first portion (11.1) and / or the second portion (11.2) in order to generate, at least in sections, at least one impeller blade (12) on the main body (11), through the use of an additive manufacturing process.

Description

[0001] Impeller for a turbomachine and method for producing an impeller

[0002] Description

[0003] The invention relates to a method having the features of independent patent claim 1, an impeller having the features of independent patent claim 17 and a turbomachine having the features of independent patent claim 18.

[0004] Impellers of turbomachinery are subjected to high mechanical loads during operation and, to achieve the highest possible efficiency and the desired operating behavior, sometimes have complex geometries. In particular, the geometry of surfaces that interact with the flow during operation can be at least partially the result of fluidic optimization and can be complex. This can affect, for example, the contouring of the impeller blades arranged on the impeller, the impeller hub, or the impeller body. These fluidic-optimized geometries can sometimes only be manufactured with sufficient precision with great effort in the manufacturing processes underlying the impeller production, which results in correspondingly high production costs.It is also important to always ensure the strongest possible connection between the rotor blades and the base body to prevent mechanical failure of the impeller during operation. Reasons for mechanical failure can include, for example, the centrifugal forces of the blades caused by high rotational speeds or the impact of foreign matter entering the impeller.

[0005] One method of manufacturing impellers for turbomachines involves machining a solid blank, with the impeller being manufactured entirely from the blank. Since the solid blank must therefore completely cover the final dimensions of the impeller, the amount of material that must be removed during production is correspondingly large. The time required to remove the material, as well as the high degree of excess material, make time- and cost-efficient production difficult.

[0006] It is therefore an object of the present invention to at least partially overcome at least one of the disadvantages described above. In particular, the object of the invention is to provide a method for producing an impeller of a turbomachine, which enables time-efficient and / or cost-effective and / or material-saving production of a preferably geometrically complex impeller.

[0007] The above object is achieved by a method having the features of independent patent claim 1, by an impeller having the features of independent patent claim 17, and by a turbomachine having the features of independent patent claim 18. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the impeller according to the invention and / or in connection with the turbomachine according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is or can always be made to each other.

[0008] According to the invention, a method is provided for producing an impeller of a turbomachine or for use in a turbomachine, comprising a base body and at least one rotor blade, wherein the base body and at least one or more rotor blades are formed.the rotor blades are integrally connected and wherein at least the following steps are carried out, preferably in the specified order: a) machining a blank formed from solid material to generate a first partial section of the base body, b) applying at least one material layer to the first partial section of the base body to generate at least one section of a second partial section of the base body by using an additive manufacturing process, c) applying at least one material layer to the first partial section and / or the second partial section to generate at least one rotor blade on the base body, at least in sections, by using an additive manufacturing process.

[0009] In other words, it is provided that in a preferably first machining step, a partial section of the base body of the impeller is first produced from a blank formed from solid material. The geometric dimensions of the first partial section are smaller in at least one dimension than the blank or the complete and / or final base body produced in the further course of the process. In particular, the blank can be smaller, at least with regard to a radial extent, than the complete and / or final base body produced in the further course of the process. Accordingly, the solid material blank used for this manufacturing step can be selected to be smaller than with other manufacturing processes, and the excess material in the impeller production can thus be reduced.

[0010] In a further, preferably second, processing step, at least one layer of material is applied to the first partial section of the base body in order to generate, at least in sections, preferably completely, a second partial section of the base body. This is done by using an additive manufacturing process, preferably for the layer-by-layer and / or precise construction of a desired geometry or the geometry of the second partial section. This allows the second partial section of the base body to be produced or generated in a particularly material-saving manner. At the same time, the use of an additive manufacturing process allows the construction of virtually any complex geometries in a comparatively simple manner. Complex operations for machining workpieces, such as, for example,Complex, multi-dimensional movement sequences when milling an impeller geometry from a solid material blank can be effectively avoided or reduced through the use of an additive manufacturing process. This reduces the time and cost required to produce an impeller. The use of an additive manufacturing process can also create a secure, preferably material-locking, connection between the first and second subsections that can withstand the high mechanical loads on the impeller during operation. In particular, this step can comprise the preferably sequential application of several, in particular a large number, of material layers. It is preferably conceivable for the second subsection to comprise at least 100, preferably at least 200, particularly preferably at least 500 material layers.

[0011] In a further, preferably third, processing step, at least one material layer is applied to the first subsection of the base body and / or the second subsection of the base body for at least partial, in particular complete, generation of at least one rotor blade, in particular all rotor blades, on the base body. This is achieved by using an additive manufacturing process, preferably for the layer-by-layer and / or precise construction of a desired geometry or the geometry of at least one rotor blade. This allows at least one rotor blade, preferably all rotor blades, of the impeller to be manufactured in a particularly material-saving manner. At the same time, the use of an additive manufacturing process allows the construction of geometries of virtually any complexity, which proves particularly advantageous with regard to highly optimized 3D blade contours.Complex workpiece machining operations, such as complex movement sequences when milling an impeller geometry from a solid material blank, can be effectively avoided or reduced. This reduces the time and cost required to manufacture an impeller. The use of an additive manufacturing process can also create a secure, preferably material-to-material connection between at least one impeller blade and the base body of the impeller or the first and / or second subsection, which can withstand the high mechanical loads the impeller experiences during operation. In particular, this step can comprise the preferably sequential application of several, in particular a large number, of material layers. Provision can be made for at least one impeller blade to comprise at least 50, preferably at least 100, particularly preferably at least 200 material layers.It can further be provided that at least one material layer applied in this step, in particular all material layers, overlaps both the first partial section and the second partial section.

[0012] Applying at least one material layer to the first and / or second subsection of the base body encompasses the idea that only a first material layer is applied directly to the first and / or second subsection and at least one subsequent material layer is applied, preferably subsequently, to the previously applied material layer and thus only indirectly to the first and / or second subsection of the base body. The idea is also encompassed that firstly several material layers, e.g., next to one another, are applied directly to the first and / or second subsection and only then is at least one subsequent layer applied to at least one previously applied material layer and thus only indirectly to the first and / or second base body.In other words, any, in particular successive, layer build-up in the course of an additive manufacturing process is encompassed by the concept of this invention, in particular at least with regard to the generation of the second partial section of the base body and / or at least one rotor blade or to steps b) and / or c).

[0013] Within the scope of the invention, it can be provided that the turbomachine is a preferably continuously operating turbomachine for compressing a fluid flow (compressor). The turbomachine can also be a turbomachine for at least partially expanding a fluid flow (turbine). The fluid guided in the turbomachine can preferably be a compressible fluid, or the turbomachine can be designed to guide a compressible fluid. The fluid can, in particular, be a gas and / or vapor.

[0014] The turbomachine can have several stages, preferably through which a fluid flow flows or can flow through successively. It can be provided that each stage comprises at least one impeller and / or one guide vane. Furthermore, the turbomachine can comprise at least one shaft, with at least one impeller, preferably all impellers, being connected to the shaft in such a way that a joint rotation of the shaft and the impeller is possible. It can also be provided that the turbomachine has several shafts, with at least one impeller connected to each shaft.

[0015] When a turbomachine is designed as a compressor, an impeller serves at least to transfer kinetic energy from a shaft to a fluid flow guided within the turbomachine. For this purpose, the impeller is set in rotation via the shaft connected to the impeller. The kinetic energy introduced into the flow by the rotation of the impeller, and in particular by the blading or rotor blades of the impeller, can be at least partially converted into pressure energy in at least one impeller and / or at least one diffuser through targeted deflection and deceleration, thus compressing or compressing the fluid flow guided through the turbomachine.

[0016] When a turbomachine is designed as a turbine, an impeller serves at least to extract kinetic energy and / or pressure energy from a fluid flow guided through the turbomachine and to transfer it to a shaft connected to the impeller or thereby to set the shaft in rotation. For this purpose, an at least partial expansion of the fluid flow guided in the turbomachine takes place in at least one impeller and / or at least one guide wheel of the turbomachine. The resulting acceleration of the fluid flow and a targeted deflection of the flow onto the impeller or in particular the impeller blades generate a torque on the shaft and thus set the shaft in rotation.

[0017] A stator of a turbomachine is a static component that serves at least to deflect the fluid flow guided within the turbomachine, enabling the most optimal possible flow to the rotor blades of a subsequent impeller in the direction of fluid flow. The blading or the guide vanes of a stator themselves can also be designed to at least partially expand or accelerate (turbine) and / or compress or decelerate (compressor) the flow.

[0018] The blades arranged on the base body of the impeller are referred to as rotor blades, which serve at least to guide the flow and / or achieve a desired flow deflection within the impeller. Depending on the operating mode of the turbomachine (compressor or turbine), a blade passage formed by two rotor blades can serve to at least partially decelerate and / or compress a fluid flow (compressor) or to at least partially expand and / or accelerate a fluid flow.

[0019] Within the scope of the invention, it can be provided that the impeller is a radial design impeller, in particular a radial compressor impeller or radial turbine impeller, and / or that the impeller is designed such that a fluid flow flows into the impeller along or substantially along an axial direction and / or a fluid flow flows out of the impeller along or substantially along a radial direction. Preferably, any circumferential components of the velocity are not taken into account in these specifications. The advantages of the method according to the invention are particularly evident in the manufacture of impeller edges of radial design. In principle, however, other impeller designs such as impellers of axial design (axial compressor impeller or axial turbine impeller) are also encompassed by the concept of the invention.This also applies to mixed forms of the above-mentioned designs, in particular to impellers of diagonal compressors.

[0020] In this case, the axial direction is oriented along or parallel to the rotation axis of the impeller and the radial direction is oriented orthogonal to the rotation axis of the impeller.

[0021] It can be provided that the base body is entirely composed of the first subsection and the second subsection, or that the first subsection and the second subsection completely form the base body. In other words, it can be provided that the base body does not comprise any further subsections besides the first subsection and the second subsection.

[0022] Within the scope of the invention, it can be provided that the base body is designed for at least partial connection to a shaft. The base body can be designed to be rotationally symmetrical at least partially, in particular completely or substantially completely. Furthermore, it can be provided that the base body is designed or functions as a support element for at least one, in particular all, of the rotor blades. In other words, it can be provided that the base body is designed to be bladeless or not to comprise any blades, in particular rotor blades. Furthermore, it can be provided that at least one rotor blade of the impeller extends at least partially over the first and the second partial section.

[0023] Within the scope of the invention, it is conceivable for the first subsection and the second subsection to be integrally connected, at least in sections. It can also be provided within the scope of the invention that at least one rotor blade is integrally connected, at least in sections, to the base body, in particular to the first subsection and / or the second subsection. A material-to-material connection achieves a particularly simple yet resilient connection between the first and second subsections or the base body and at least one rotor blade.

[0024] It can be provided within the scope of the invention that at least two steps of a method according to the invention run simultaneously at least in sections or overlap in their execution at least in sections. In particular, this can relate to at least steps b) and c). Thus, it is conceivable that while at least one material layer is being applied to the first section of the base body to generate a second section of the base body, at least one material layer is also being applied to at least the first section of the base body to generate at least one rotor blade. This can accelerate the manufacturing process. It is also conceivable that at least one step, preferably at least steps b) and / or c), are carried out repeatedly during the manufacture of an impeller.

[0025] Within the scope of the invention, it may be advantageous for the material layer to be applied in step b) and / or step c) by deposition welding, preferably by laser deposition welding, in particular using an additive. In laser deposition welding, the surface of a workpiece, in particular of the base body, is locally melted by a laser while an additive is simultaneously applied to the molten surface. Under the action of the laser or in the immediate vicinity of the molten workpiece surface, the additive also melts and bonds firmly to the workpiece. By adding the additive, a local material increase on the workpiece can be realized, so that, in particular by repeatedly carrying out this process, the desired geometry can be built up, preferably layer by layer, on an existing workpiece (in this case the base body).In other words, by arranging several welding tracks or welding beads at least in sections next to one another and / or one above the other or overlapping on a surface of a workpiece, in particular of the first and / or second partial section of the base body, a 3D geometry can be built up on the workpiece surface, preferably layer by layer.

[0026] During laser deposition welding, an additive can preferably be added in powder form or as a solid, for example as a rod or wire. The additive can be made of the same material as the workpiece to which the additive is applied. In particular, the additive can be made of the same material as the first and / or second sub-section of the base body. The deposition welding can be carried out at least partially continuously, in particular along a previously defined contour or a previously defined path, on a workpiece surface or a surface of the first and / or second sub-section. By generating a geometry, preferably layer by layer, using an additive manufacturing process, in particular by deposition welding, the desired geometry of the base body can be generated reliably and with little or no excess material.

[0027] Within the scope of the invention, it can be provided that a rotational axis of the first subsection and a rotational axis of the second subsection are arranged coaxially. In other words, it can be provided that the first subsection and the second subsection are rotationally symmetrical at least in sections, and the respective rotational axes of the first and second subsections are arranged coaxially.

[0028] Furthermore, within the scope of the invention, it can be provided that the second subsection encloses the first subsection at least partially, in particular completely. In other words, it can be provided that the material layer applied to the first subsection at least in step b) extends at least partially over an outer circumference or an outer circumferential surface of the first subsection and thus encloses the first subsection at least partially.

[0029] It is conceivable that the first subsection extends at least between a first inner radius and a first outer radius, and that the second subsection extends at least between a second inner radius and a second outer radius, wherein the first outer radius is preferably equal to the second inner radius. Additionally or alternatively, it can be provided that the second subsection is generated on an axially or substantially axially extending outer surface of the first subsection.

[0030] Within the scope of the invention, it is conceivable that the first sub-section and the second sub-section of the base body are formed at least in sections from the same material or from a uniform material and / or that at least one sub-section, in particular the first and / or the second sub-section, of the base body and at least one rotor blade are formed at least in sections from the same material or from a uniform material. This results in a particularly high load-bearing capacity and / or longevity of the impeller. Furthermore, in particular with regard to production using an additive manufacturing process, in particular build-up welding, a particularly reliable connection is obtained between the first and second sub-sections and / or at least one rotor blade and the first and / or second sub-section.

[0031] Within the scope of the invention, it can be provided that at least one subsection of the base body, in particular the first and / or the second subsection, and / or at least one rotor blade are manufactured or formed at least in sections from a martensitic and / or precipitation-hardened steel. In particular, it can be provided that the impeller is manufactured or formed entirely from a martensitic and / or precipitation-hardened steel. This results in the advantage of cost-effective production of the impeller while simultaneously achieving high mechanical strength. Furthermore, such a material has proven to be advantageous in terms of its processability with regard to its use in an additive manufacturing process, in particular build-up welding.

[0032] According to the invention, it is conceivable that the steel contains at least one of the following alloying elements in the specified amount:

[0033] • 10% to 20%, preferably 13% to 18%, particularly preferably 15% to 17% chromium,

[0034] • 1% to 7%, preferably 2% to 6%, particularly preferably 3% to 5% nickel,

[0035] • 1% to 7%, preferably 2% to 6%, particularly preferably 3% to 5% copper. The stated percentages refer to the mass fraction of the respective alloying element contained in the steel (mass fraction). A steel comprising at least one of the above-mentioned alloying elements in the respectively stated amount has proven particularly advantageous with regard to processability in a method according to the invention as well as to the load-bearing capacity and durability of the impellers manufactured therefrom. Particularly good results were observed with a steel alloy that contains all alloying elements in the stated amounts, in particular 15% to 17% chromium, 3% to 5% nickel and 3% to 5% copper.

[0036] It is also conceivable that the steel has at least one of the following material characteristics:

[0037] • Tensile strength (R m ) from 900 to 1400 N / mm 2 , preferably from 1000 to 1300 N / mm 2 , particularly preferably from 1070 to 1270 N / mm 2 ,

[0038] • Yield strength (R P o,2) of at least 800 N / mm 2 , preferably of at least 900 N / mm 2 , particularly preferably of at least 1000 N / mm 2 ,

[0039] • Young's modulus from 100 to 300 kN / mm 2 , preferably from 150 to 250 kN / mm 2 , particularly preferably from 180 to 220 kN / mm 2 in particular of 200 kN / mm 2 ,

[0040] • Elongation at break (As) of at least 5%, preferably of at least 8%, particularly preferably of at least 10%,

[0041] • Hardness (HB30) from 250 to 450 HB, preferably from 300 to 400 HB, particularly preferably from 330 to 390 HB,

[0042] • Notched impact strength of at least 10J, preferably at least 15J, particularly preferably at least 20J.

[0043] All information on material properties applies to a temperature of 20°C (degrees Celsius). A steel that exhibits at least one of the above-mentioned material properties within the specified range has proven particularly advantageous with regard to the mechanical load-bearing capacity of the impellers manufactured from it. This applies particularly to a steel that exhibits all of the above-mentioned material properties within the specified ranges, in particular to a steel with a tensile strength of 1070 N / mm² to 1270 N / mm². 2 , a yield strength of at least 1000 N / mm 2 , an elastic modulus of 200 N / mm 2an elongation at break of at least 10%, a hardness of 330 HB to 390 HB and a notched impact strength of at least 20 J. Furthermore, it can be provided within the scope of the invention that at least one sub-section, in particular the first and / or the second sub-section, of the base body and / or at least one rotor blade is made or formed at least in sections from a titanium material. It can also be provided that the impeller is made or formed entirely from a titanium material. This results in the advantage of a particularly lightweight construction of the impeller with simultaneous high mechanical load-bearing capacity. Furthermore, such a material has proven to be positive in terms of its processability with regard to its use in an additive manufacturing process, in particular build-up welding.

[0044] It is conceivable that the titanium material contains at least one of the following alloying elements in the specified amount:

[0045] • 3% to 10%, preferably 5% to 8%, particularly preferably 5.5% to 6.75% aluminum,

[0046] • 1% to 7%, preferably 3% to 6%, particularly preferably 3.5% to 4.5% vanadium.

[0047] The specified percentages refer to the mass fraction of the respective alloying element contained in the titanium material (mass fraction). A titanium material comprising at least one of the above-mentioned alloying elements in the respective specified amount has proven particularly advantageous with regard to processability within the scope of a method according to the invention, as well as with regard to the load-bearing capacity and durability of the impellers produced therefrom, while simultaneously maintaining a low weight of the impellers. Particularly good results were observed with a titanium material containing all alloying elements in the specified amounts, in particular 5.5% to 6.75% aluminum and 3.5% to 4.5% vanadium.

[0048] It is also conceivable within the scope of the invention that the titanium material has at least one of the following material characteristics:

[0049] • Tensile strength (R m ) of at least 700 N / mm 2 , preferably of at least 850 N / mm2 , particularly preferably at least 895 N / mm 2 ,

[0050] • Yield strength (R P o,2) of at least 700 N / mm 2 , preferably of at least 800 N / mm 2 , particularly preferably of at least 828 N / mm 2 , • Young's modulus of 80 kN / mm 2 up to 130 kN / mm 2 , preferably 100 kN / mm 2 up to 120 kN / mm 2 , particularly preferably 110 kN / mm 2 up to 115 kN / mm 2 in particular of 114 kN / mm 2 ,

[0051] • Elongation at break (As) of at least 5%, preferably of at least 8%, particularly preferably of at least 10%,

[0052] • Hardness (HB30) from 200 HB to 350 HB, preferably from 250 HB to 330 HB, particularly preferably from 300 HB to 320 HB,

[0053] All information on material properties applies to a temperature of 20°C (degrees Celsius). A titanium material that exhibits at least one of the above-mentioned material properties within the specified range has proven particularly advantageous with regard to the mechanical strength of the impellers made from it, as well as the processability of this material. This applies in particular to a titanium material that exhibits all of the above-mentioned material properties within the specified ranges, in particular to a titanium material with a tensile strength of at least 895 N / mm 2 , a yield strength of at least 828 N / mm 2 , an elastic modulus of 114 N / mm 2 , an elongation at break of at least 10% and a hardness of 300 HB to 320 HB.

[0054] Within the scope of the invention, it can be provided that the method is at least partially automated, in particular by at least one manufacturing robot. In particular, it is conceivable that at least steps b) and c) are performed by a welding robot. It can also be provided that at least step a) or a machining operation of the impeller, in particular of the base body, is performed by an at least partially automated lathe and / or milling machine.

[0055] Furthermore, it can be provided that a CAD model of the impeller geometry serves as the basis for at least one step of the method. In other words, it can be provided that, in particular before step a), control commands for at least one production robot are defined on the basis of a CAD model of the impeller, for at least partially executing at least one step of the method according to the invention. Thus, on the basis of the CAD model, at least one movement sequence and / or at least one associated movement speed of at least one processing head of at least one production robot can be defined in order to produce or realize the desired impeller geometry, at least in sections. Within the scope of the invention, it is optionally possible that, in addition, preferably after step b), at least the following steps are carried out:

[0056] • At least partially edit the first and / or second subsection

[0057] (11.1 , 11.2), preferably by applying a cutting

[0058] Manufacturing method for producing a surface course that is at least partially continuous over the first and second partial sections (11.1, 11.2).

[0059] In this context, it can be provided that the machining of the first and second partial sections takes place by turning, wherein finishing of at least one surface of the base body is preferably carried out during the turning in order to produce a surface profile that is continuous at least in sections over the first and second partial sections. In this way, the surface quality of the base body can be improved at least in sections in order to reduce flow losses during operation of the impeller. In this way, the base body can also be optimally prepared for the subsequent generation of at least one rotor blade and the desired final geometry of the first and second partial sections can be produced with high precision and / or with close tolerances. Accordingly, this machining step can preferably be carried out at least on the section orthe surface of the base body, in particular of the first and / or second partial section, on which at least one rotor blade is generated in step c).

[0060] Furthermore, it can be provided within the scope of the invention that, in addition, preferably after step c), at least the following steps are carried out:

[0061] • Carrying out at least one heat treatment to improve the mechanical properties of the impeller,

[0062] • At least section-wise machining of the first sub-section and / or the second sub-section and / or at least one rotor blade, preferably by applying a machining process, at least to remove superfluous material and / or produce a required surface quality,

[0063] • Balancing the impeller,

[0064] • Cleaning the impeller, preferably by blasting. With regard to carrying out a heat treatment, in particular in the case of an impeller which is made at least partially or completely from steel, it can be provided that the impeller is heated at least temporarily to a temperature of at least 400 °C, preferably at least 500 °C, particularly preferably to a temperature of at least 550 °C or exactly or substantially exactly 550 °C. It can also be provided that the period in which the impeller is kept at an elevated temperature is at least 2 hours, preferably at least 3 hours, particularly preferably at least 4 hours or 4 hours. This made it possible to achieve particularly advantageous precipitation hardening of the steel material and high mechanical load-bearing capacity of the impeller.A heat treatment involving heating the impeller to exactly or essentially exactly 550°C and maintaining this temperature for a period of 5 hours has proven particularly advantageous. The impeller can then be cooled to room temperature.

[0065] With regard to carrying out a heat treatment, in particular in the case of an impeller which is made at least partially or completely from a titanium material, it can be provided that the impeller is heated at least temporarily to a temperature of at least 450 °C, preferably at least 550 °C, particularly preferably to a temperature of at least 600 °C or exactly or substantially exactly 600 °C. It can also be provided that the period in which the impeller is kept at an elevated temperature is at least 1 hour, preferably at least 1.5 hours, particularly preferably at least 2 hours or 2 hours. As a result, a particularly high mechanical load-bearing capacity of the impeller could be achieved. A heat treatment comprising heating the impeller to exactly or substantially exactly 600 °C and maintaining this impeller temperature for a period of 2 hours has proven particularly advantageous.The impeller can then be cooled to room temperature. Cooling the impeller can comprise cooling the impeller to at least one intermediate temperature and at least temporarily holding the impeller at this intermediate temperature. Provision can be made for the impeller to be held at an intermediate temperature for a period of at least 0.5 hours, preferably at least 1 hour or at least 2 hours. An intermediate temperature can preferably be 200°C. This results in the advantage of a further improvement in the mechanical properties of the impeller. The information essentially relates to tolerances that must be taken into account and which can arise due to manufacturing or process reasons. For example, heating in an oven can lead to slight temporal and / or local temperature fluctuations.The geometry of a workpiece is also always subject to manufacturing-related inaccuracies (tolerances), the magnitude of which depends on the processes and / or tools and / or machines used.

[0066] The heat treatment of the impeller, especially in the case of an impeller made at least partially or entirely of a titanium material, can be carried out at least partially in a vacuum. It is conceivable that the heat treatment of the impeller is carried out, or can be carried out, at least partially in a vacuum furnace. This can, in particular, prevent oxidation of the impeller during heat treatment and the resulting disadvantages with regard to the mechanical properties of the impeller.

[0067] With regard to at least partially machining the first subsection and / or the second subsection and / or at least one rotor blade, at least to remove excess material and / or achieve a required surface quality, the advantage is a particularly lightweight impeller design and / or a high surface quality to prevent flow losses. Machining can preferably be carried out by turning and / or milling.

[0068] With regard to at least section-wise machining of the first sub-section and / or the second sub-section at least for the purpose of removing superfluous material and / or producing a required surface quality, it can be provided that this takes place at least on a bladeless surface of the base body or of the first and / or second sub-section. In other words, the machining can take place at least on a surface of the base body or of the first and / or second sub-section on which no rotor blade is arranged and / or which is opposite the surface on which at least one rotor blade, preferably all rotor blades, are arranged. The machining can be a final machining operation or can serve to generate the final base body geometry. With regard to balancing the impeller, it can be provided that at least one counterweight is arranged on the impeller to compensate for any imbalance.Preferably, the counterweight can be welded on. Additionally or alternatively, material can be removed from at least one position on the impeller, preferably using a machining process such as drilling or milling, to compensate for any imbalance in the impeller. It can also be provided that during balancing, the impeller is accelerated at least once to a rotational speed of 1000 revolutions per minute and then decelerated again, in particular to a rotational speed of 0 revolutions per minute.

[0069] With regard to cleaning the impeller by blasting, it can be provided that a spherical or granular blasting medium is used. In particular, a cast stainless steel blasting medium can be used as the blasting medium or the blasting medium can be formed or manufactured at least partially, in particular entirely, from stainless steel. It can be provided that the blasting medium has a diameter or a grain size between 0.05 mm and 0.6 mm, in particular between 0.09 mm and 0.5 mm. Particularly preferably, the blasting medium can have a diameter or a grain size between 0.05 mm and 0.315 mm or between 0.14 mm and 0.5 mm. The use of a blasting medium in accordance with the above information has been shown to offer the advantage of a particularly high degree of cleaning and a particularly high surface quality of the impeller.

[0070] With regard to the present invention, it is conceivable that at least the machining in step a) is carried out using at least one machining process, preferably by turning and / or milling. The machining can be at least partially automated, thereby reducing the tolerances with respect to the impeller geometry.

[0071] It can be provided within the scope of the invention that in addition, preferably before step a) and / or before step b) and / or before step c), at least the following step is carried out:

[0072] • Introducing the blank formed from solid material and / or the first and / or second partial section into the interior of a processing chamber, • Closing the processing chamber,

[0073] • Creating an inert gas atmosphere in the interior of the processing chamber, wherein in particular the oxygen content in the inert gas atmosphere is 100 ppm or less and / or the water content in the inert gas atmosphere is 100 ppm or less,

[0074] • Opening the processing chamber and removing the base body or at least a partial section of the base body and / or the impeller.

[0075] In this case, it can be provided that the blank is first introduced into the processing chamber, which is then sealed, and then the inert gas atmosphere is created in the processing chamber. Alternatively, it is conceivable that an inert gas atmosphere is first created in the processing chamber and the blank is then introduced into the processing chamber, in particular via a lock. Furthermore, the processing chamber can be sealed in such a way that an exchange of atmosphere between the interior of the processing chamber and the external environment of the processing chamber is prevented or substantially prevented, in particular as long as the processing chamber is sealed.

[0076] It is conceivable within the scope of the invention that at least one step of the method according to the invention takes place under an inert gas atmosphere. In other words, it can be provided that the manufacture of the impeller takes place at least partially while the impeller is preferably completely or essentially completely surrounded by an inert gas. Helium or argon can preferably be used as the inert gas. The use of further (different) inert gases or a mixture of at least two inert gases is also encompassed by the concept of the invention. By machining the impeller blank or the base body under an inert gas atmosphere, oxidation of the workpiece surface can be effectively avoided. Machining under an inert gas atmosphere has proven particularly advantageous when using a titanium material.It can be provided that the oxygen content in the inert gas atmosphere is 100 ppm (parts per million) or less, in particular 80 ppm or less, preferably 50 ppm or less. In particular, an oxygen content of 50 ppm or less has proven advantageous with regard to effectively preventing oxidation. It is also conceivable that the water content (H2O) in the inert gas atmosphere is 100 ppm or less, in particular 80 ppm or less, preferably 50 ppm or less. In particular, a water content of 50 ppm or less has proven particularly advantageous in the context of a manufacturing method according to the invention with regard to the production of high-quality workpieces.

[0077] It can further be provided that at least one step of the method is carried out in the interior of a processing chamber, wherein in particular the interior of the processing chamber is hermetically sealed or substantially hermetically sealed from the external environment of the processing chamber at least during the execution of at least one method step and / or is filled or substantially filled with an inert gas. In other words, it can be provided that the execution of at least one method step in the processing chamber only takes place once an inert gas atmosphere has been created in the processing chamber. This can be done by evacuating the processing chamber, in particular using a vacuum pump, and subsequently filling the processing chamber with an inert gas.Also, or alternatively, the processing chamber can be purged with an inert gas until the desired inert gas atmosphere is created. The processing chamber can be hermetically sealed from the external environment of the processing chamber, so that no or essentially no exchange of atmosphere occurs between the interior of the processing chamber and the external environment of the processing chamber as long as the chamber is hermetically sealed. The processing chamber can comprise at least one oxygen sensor with which an oxygen concentration in the processing space of the processing chamber can be detected.

[0078] Within the scope of the invention, it can be provided that all method steps or only individual method steps are carried out in the processing chamber. It can also be provided that the workpiece (the impeller) is removed from the processing chamber between individual method steps and is introduced back into the processing chamber before a subsequent method step, or that the workpiece remains in the processing chamber for several successive method steps. With regard to step a), a blank made of solid material can be introduced into the processing chamber before step a), and after step a) the first partial section of the base body can be removed from the processing chamber. With regard to step b), the first partial section of the base body can be introduced into the processing chamber before step b), and after step b) the base body consisting of the first and second partial sections can be removed.With regard to step c), the base body can be introduced into the processing chamber before step c) and the impeller comprising the base body and at least one rotor blade can be removed after step c).

[0079] Furthermore, within the scope of the invention, it can be provided that the impeller, preferably after completion of the method according to the invention, has a diameter of at least 400 mm, in particular at least 450 mm, preferably at least 500 mm, particularly preferably at least 560 mm, or exactly or substantially exactly 560 mm. With regard to impellers with the above-mentioned diameter, the manufacturing method according to the invention has proven particularly effective. This applies in particular to impellers with a diameter of exactly or substantially exactly 560 mm.

[0080] It is also conceivable that the impeller, preferably after completion of the method according to the invention, has an axial extent, in particular along an axial direction, of at least 150 mm, in particular at least 170 mm, preferably at least 180 mm, particularly preferably at least 190 mm, or exactly or substantially exactly 190.4 mm. With regard to impellers with the above-mentioned axial extent, the manufacturing method according to the invention has proven particularly effective. This applies in particular to impellers with an axial extent of exactly or substantially exactly 190.4 mm.

[0081] Within the scope of the invention, it can be provided that at least one rotor blade has a greater material thickness on the side facing the base body than on the opposite side or side facing away from the base body. In other words, at least one rotor blade can have a greater material thickness near the base body or at its blade root than at its blade tip. By increasing the material thickness in the region of the blade root, a more resilient connection between the rotor blade and the base body can be achieved and failure of the rotor blade during operation of the impeller can be avoided. The material thickness can then be successively reduced, starting from the base body or blade root, to the intended material thickness of the rotor blade. In particular, it is conceivable for at least one rotor blade to have a greater material thickness on its side facing away from the base body orthe blade tip has a material thickness twice as great as that on the side facing the base body or the blade root.

[0082] It can further be provided within the scope of the invention that step c) is carried out multiple times and at least one material layer of at least one rotor blade has a smaller layer width than the previously applied material layer of the same rotor blade. The layer width determines the material thickness of the rotor blade in the section of the rotor blade formed by the material layer. Thus, the material thickness of the rotor blade can be varied in a targeted manner, at least in sections, by varying the layer width of the applied material layers, for example in order to increase the mechanical load-bearing capacity of the rotor blade in the region of the blade root or on the side facing the base body. In other words, it can therefore be provided that at least one rotor blade has a smaller layer width along its extension, starting from the base body orits blade root has a material thickness which varies at least in sections, preferably decreases at least in sections, in the direction of its blade tip, wherein the material thickness is preferably higher at the blade root than at the blade tip.

[0083] The above object is further achieved by an impeller according to the invention comprising a base body and at least one rotor blade, wherein the impeller was manufactured according to a method according to the invention or was manufactured according to a method according to one of claims 1 to 16. With regard to an impeller according to the invention, the same advantages arise as were explained with regard to the method according to the invention.

[0084] The above object is further achieved by a turbomachine according to the invention comprising at least one impeller according to claim 17. With regard to the turbomachine, the same advantages arise as have been explained with regard to the impeller.

[0085] Further advantages, features, and details of the invention will become apparent from the following description, in which several embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. In the drawings:

[0086] Fig. 1 is a perspective view of an impeller according to the invention

[0087] Fig. 2 is a sectional view of an impeller according to the invention,

[0088] Fig. 3 is a schematic representation of a method according to the invention,

[0089] Fig. 4 is a schematic representation of a processing according to step a),

[0090] Fig. 5 is a schematic representation of a processing according to step b),

[0091] Fig. 6 a perspective view of a base body of an impeller according to the invention

[0092] Fig. 7 a schematic representation of a processing according to step c)

[0093] Fig. 8 a blank made of solid material in a processing chamber and

[0094] Fig. 9 shows a schematic structure of a rotor blade.

[0095] Fig. 1 shows a perspective view of an impeller 10 according to the invention for use in a turbomachine. The impeller 10 is a radial-type impeller 10 designed as a radial compressor impeller. The impeller 10 comprises a base body 11 and at least a plurality of rotor blades 12. The base body 11 further comprises a first subsection 11.1 and a second subsection 11.2, which are described in more detail below. The rotor blades 12 are arranged on the base body 11 of the impeller 10 and are integrally connected to the base body 11. The first subsection 11.1 and the second subsection 11.2 are also integrally connected. Furthermore, the first subsection 11.1, the second subsection 11.2, and the rotor blades 12 of the impeller 10 are made of the same material or are formed from a uniform material. The flow through the impeller 10 occurs along the rotor blades 12 from the leading edge 18 towards the trailing edge 19.Fig. 2 shows a sectional view of an impeller 10 according to the invention, wherein the sectional plane intersects the axis of rotation or central axis of the impeller 10. The impeller 10 is designed such that an inflow of a fluid flow into the impeller 10 occurs or can occur along an axial direction X and an outflow of a fluid flow from the impeller 10 occurs or can occur along a radial direction R. The axial direction X is oriented parallel to the axis of rotation M of the impeller 10 and the radial direction R is oriented orthogonal to the axis of rotation M of the impeller 10. The axis of rotation M is arranged coaxially with the axis of rotation M1 of the first subsection 11.1 and with the axis of rotation M2 of the second subsection 11.2.

[0096] Fig. 3 shows a schematic representation of a method 100 according to the invention for producing an impeller 10 of a turbomachine or for use in a turbomachine, comprising a base body 11 and at least one rotor blade 12, wherein the base body 11 and the rotor blade 12 are materially connected and wherein at least the following steps are carried out, preferably in the specified order: a) machining a blank 1 formed from solid material to generate a first partial section 11.1 of the base body 11, b) applying at least one material layer 13 to the first partial section 11.1 of the base body 11 to at least partially generate a second partial section 11.2 of the base body 11 by applying an additive manufacturing method, c) applying at least one material layer 13 to the first partial section 11.1 and / or the second partial section 11.2 for at least partially generating at least one rotor blade 12 on the base body 11 by applying an additive manufacturing process.

[0097] The method 100 is explained in more detail below. Fig. 4 schematically shows a machining of a blank 1 according to the invention according to step a). The blank 1 is shown on the left and is formed from solid material. The blank 1 is machined in step a), preferably using a machining process, so that the first partial section 11.1 of the base body 11 shown on the right-hand side of Fig. 4 is generated from the blank 1. The first partial section 11.1 of the base body 11 is rotationally symmetrical. The areas in which material was removed from the blank 1 in order to generate the geometry of the first partial section 11.1 are marked by dashed lines in the illustration of the first partial section 11.1 in Fig. 4 for the purpose of clarity.

[0098] Fig. 5 schematically shows a processing according to the invention of the base body 11 or of the first partial section 11.1 of the base body 11 according to step b). On the left side of Fig. 5, the first partial section 11.1 of the base body 11 is shown after the processing carried out in step a). On the right side, the base body, comprising a first partial section 11.1 and a second partial section 11.2, is shown after the processing in step b). In step b), the application 102 of a plurality of material layers 13 to the first partial section 11.1 of the base body 11 takes place in order to generate or build up a second partial section 11.2 of the base body 11, in particular layer by layer. This is done by using an additive manufacturing process in order to build up the second partial section 11.2 successively starting from the surface of the first partial section 11.1. The first subsection forms 11.1 and the second subsection forms 11.2 at least one common surface 15 of the base body 11, on which subsequently at least one rotor blade 12 can be or is generated.

[0099] In this case, the second subsection 11.2 is generated by laser deposition welding and thus by a material buildup on the first subsection 11.1, whereby the second subsection 11.2 is generated by the successive application 102 of several material layers 13 or welding traces. This results in a materially bonded connection between the first subsection 11.1 and the second subsection 11.2.

[0100] The additive used to generate the second subsection 11.2 during the build-up welding process is made of the same material as the solid blank 1 or the first subsection 11.1 of the base body 11. Thus, the first subsection 11.1 and the second subsection 11.2 of the base body 11 are made of the same material.

[0101] Fig. 5 shows that the second subsection 11.2 completely encloses the first subsection 11.1. The second subsection 11.2 is rotationally symmetrical, and the rotation axis or central axis M2 of the second subsection 11.2 is arranged coaxially with the rotation axis or central axis M1 of the first subsection 11.1.

[0102] Starting from Fig. 5, at least section-wise machining of the first subsection 11.1 and the second subsection 11.2 can be carried out in order to ensure a continuous surface profile and / or a high surface quality of the surface 15.

[0103] For clarity, Fig. 6 shows a perspective view of the base body 11 comprising a first subsection 11.1 and a second subsection 11.2. The first subsection 11.1 and the second subsection 11.2 completely form the base body 11. Based on the base body geometry shown in Fig. 6, one or more rotor blades 12 can now be generated on the surface 15 of the base body 11.

[0104] Fig. 7 schematically shows a processing according to the invention of the base body 11 or of the first partial section 11.1 and the second partial section 11.2 of the base body 11 according to step c). On the left side of Fig. 7, the base body 11 is shown after the processing carried out in step b). On the right side, the impeller 10, comprising a base body 11 with a first partial section 11.1 and a second partial section 11.2 as well as at least one rotor blade 12, is shown after the processing in step c). In step c), the application 103 of a plurality of material layers 13 to the first partial section 11.1 and the second partial section 11.2 of the base body 11 takes place in order to generate or build up at least one rotor blade 12, in particular a plurality of rotor blades 12, on the base body 11, preferably layer by layer.This is achieved by applying an additive manufacturing process to successively build at least one rotor blade 12 starting from the surface 15 of the base body 11. At least one rotor blade 12 extends at least partially over the first subsection 11.1 and the second subsection 11.2 of the base body.

[0105] In the present case, at least one rotor blade 12 is generated by laser deposition welding and thus by a material buildup on the surface 15 of the base body 11 formed by the first subsection 11.1 and the second subsection 11.2. The rotor blade 12 is generated by the successive application 103 of several material layers 13 or welding traces. This consequently results in a material-to-material connection between the base body 11 and at least one rotor blade 12, in particular all rotor blades 12. The rotor blades 12 are depicted in Fig. 7 only schematically and in a geometrically simplified manner.

[0106] The additive used to generate the second subsection 11.2 during the build-up welding process is made of the same material as the first subsection 11.1 and the second subsection 11.2 of the base body 11. Thus, the first subsection 11.1 and the second subsection 11.2, as well as the rotor blades 12 of the base body 11, are made of the same material.

[0107] Starting from Fig. 7, further processing steps can be performed on the impeller 10. Thus, at least one section-wise machining of the first subsection 11.1 and / or the second subsection 11.2 and / or at least one rotor blade 12 can be performed to remove excess material. Heat treatment of the impeller 10 can also be performed, balancing of the impeller 10 can be performed, and / or cleaning of the impeller 10 can be performed.

[0108] Fig. 8 schematically shows a blank 1 made of solid material in the interior 14.1 of a processing chamber 14, so that at least step a), but in particular also at least steps b) and c), can be carried out in the processing chamber 14. The interior 14.1 can be hermetically sealed from the external environment of the processing chamber 14 or is hermetically sealed when at least one process step is being carried out. Thus, at least one processing step can be carried out under an inert gas atmosphere, which was previously created by evacuating the interior 14.1 or filling the interior 14.1 with an inert gas. By processing the impeller blank or the base body 11 under an inert gas atmosphere, oxidation of the workpiece surface can be effectively avoided.

[0109] Fig. 9 shows a highly simplified view of a rotor blade 12 on the surface 15 of the base body, with the viewing direction along the central axis M directed towards the leading edge 18. The illustration shown in Fig. 9 is intended solely to illustrate the layered structure of a rotor blade 12. The rotor blade 12 consists of several material layers 13 which were applied one after the other to the surface 15 or to the respective preceding material layer 13 using an additive manufacturing process. By applying each material layer 13, an increase in material is realized on the rotor blade 12 or on the base body 11, whereby the geometry of the rotor blade 12 can be generated reliably and in a material-saving manner.

[0110] The rotor blade 12 has a greater material thickness T on the side facing the base body 11 or at the blade root 17 than on the side facing away from the base body 11 or at the blade tip 16. By increasing the material thickness in the area of ​​the blade root 17, a more resilient connection of the rotor blade 12 to the base body 11 can be achieved and failure of the rotor blade 12 during operation of the impeller 10 can be avoided.

[0111] The greater material thickness in the region of the blade root 17 was achieved in that in step c) one or more material layers 13 with a first layer width T were first applied and then at least one material layer 13 with a second layer width T was applied, wherein the second layer width T is smaller than the first layer width T. By changing the layer width T of the material layers 13 applied to the base body 11, the material thickness T of the rotor blade 12 can be varied starting from the base body 11 along the extension of the rotor blade 12 between the blade root 17 and the blade tip 16.

[0112] B ez uqs ze ichenli ste

[0113] 1 blank

[0114] 10 Wheel

[0115] 11 Basic body

[0116] 11.1 First section

[0117] 11.2 Second section

[0118] 12 blades

[0119] 13 material layers

[0120] 14 Processing chamber

[0121] 14.1 Interior

[0122] 15 Surface

[0123] 16 Shovel tip

[0124] 17 Blade foot

[0125] 18 leading edge

[0126] 19 trailing edge

[0127] 100 procedures

[0128] 101 Edit

[0129] 102 Application

[0130] 103 Application

[0131] M Central axis / rotation axis

[0132] M1 central axis / rotation axis

[0133] M2 central axis / rotation axis

[0134] R Radial direction

[0135] T Material thickness / layer width

[0136] X Axial direction

Claims

Patent claims Method (100) for producing an impeller (10) of a turbomachine, comprising a base body (11) and at least one rotor blade (12), wherein the base body (11) and the rotor blade (12) are integrally connected and wherein at least the following steps are carried out, preferably in the specified order: a) machining (101) of a blank (1) formed from solid material to generate a first partial section (11.1) of the base body (11), b) applying (102) at least one material layer (13) to the first partial section (11.1) of the base body (11) to at least partially generate a second partial section (11.2) of the base body (11) by applying an additive manufacturing process, c) applying (103) at least one material layer (13) to the first partial section (11.1) and / or the second partial section (11.2) for generating at least one rotor blade (12) on the base body (11) at least in sections, by applying an additive manufacturing process. Method (100) according to claim 1, characterized in that the application (102, 103) of the material layer (13) in step b) and / or step c) is carried out by deposition welding, preferably by laser deposition welding. Method (100) according to one of the preceding claims, characterized in that an axis of rotation (M1) of the first subsection (11.1) and an axis of rotation (M2) of the second subsection (11.2) are arranged coaxially and / or that the second subsection (11.2) encloses the first subsection (11.1) at least in sections. Method (100) according to one of the preceding claims, characterized in that the first subsection (11.1) and the second subsection (11.2) of the base body (11) are formed at least in sections from the same material and / or that at least one subsection (11.1, 11.2) of the base body (11) and at least one rotor blade (12) are formed at least in sections from the same material. Method (100) according to one of the preceding claims, characterized in that at least one subsection (11.1, 11.2) of the base body (11) and / or at least one rotor blade (12) are formed at least in sections from a martensitic, precipitation-hardened steel. Method (100) according to claim 5, characterized in that the steel contains at least one of the following alloying elements in the specified amount: • 10% to 20%, preferably 13% to 18%, particularly preferably 15% to 17% chromium, • 1% to 7%, preferably 2% to 6%, particularly preferably 3% to 5% nickel, • 1% to 7%, preferably 2% to 6%, particularly preferably 3% to 5% copper. Method (100) according to one of claims 5 or 6, characterized in that the steel has at least one of the following material characteristics: • Tensile strength (R m ) of 900 N / mm 2 up to 1400 N / mm 2 , preferably 1000 N / mm 2 up to 1300 N / mm 2 , particularly preferably 1070 N / mm 2 up to 1270 N / mm 2 , • Yield strength (R P o,2) of at least 800 N / mm 2 , preferably of at least 900 N / mm 2 , particularly preferably of at least 1000 N / mm 2 , • Young's modulus from 100 to 300 kN / mm 2 , preferably 150 kN / mm 2 up to 250 kN / mm 2 , particularly preferably 180 kN / mm 2 up to 220 kN / mm 2 in particular of 200 kN / mm2 , • Elongation at break (As) of at least 5%, preferably of at least 8%, particularly preferably of at least 10%, • Hardness (HB30) from 250 HB to 450 HB, preferably from 300 HB to 400 HB, particularly preferably from 330 HB to 390 HB, • Notched impact strength of at least 10 J, preferably at least 15 J, particularly preferably at least 20 J. The method (100) according to any one of the preceding claims, characterized in that at least one partial section (11.1, 11.2) of the base body (11) and / or at least one rotor blade (12) is made at least partially from a titanium material. The method (100) according to claim 8, characterized in that the titanium material contains at least one of the following alloying elements in the specified amount: • 3% to 10%, preferably 5% to 8%, particularly preferably 5.5% to 6.75% aluminum, • 1% to 7%, preferably 3% to 6%, particularly preferably 3.5% to 4.5% vanadium. Method (100) according to one of claims 8 or 9, characterized in that the titanium material has at least one of the following material characteristics: • Tensile strength (R m ) of at least 700 N / mm 2 , preferably of at least 850 N / mm 2 , particularly preferably at least 895 N / mm 2 , • Yield strength (R P o,2) of at least 700 N / mm 2 , preferably of at least 800 N / mm 2 , particularly preferably of at least 828 N / mm 2 , • Young's modulus of 80 kN / mm 2 up to 130 kN / mm 2 , preferably 100 kN / mm 2 up to 120 kN / mm 2 , particularly preferably 110 kN / mm 2 up to 115 kN / mm 2 in particular of 114 kN / mm 2 , • Elongation at break (As) of at least 5%, preferably of at least 8%, particularly preferably of at least 10%, • Hardness (HB30) from 200 HB to 350 HB, preferably from 250 HB to 330 HB, particularly preferably from 300 HB to 320 HB. Method (100) according to one of the preceding claims, characterized in that, in addition, preferably after step b), at least the following steps are carried out: • Machining the first and / or second partial section (11.1, 11.2) at least in sections, preferably by applying a machining process, at least to produce a surface profile that is at least partially continuous over the first and second partial section (11.1, 11.2) and / or a required surface quality. Method (100) according to one of the preceding claims, characterized in that additionally, preferably after step c), at least the following steps are carried out: • Carrying out at least one heat treatment to improve the mechanical properties of the impeller (10), • At least section-wise machining of the first sub-section (11.1) and / or the second sub-section (11.2) and / or at least one rotor blade (12), preferably by applying a machining process, at least to remove superfluous material (11) and / or to produce a required surface quality, • Balancing the impeller (10), • Cleaning the impeller (10), preferably by blasting. Method (100) according to one of the preceding claims, characterized in that at least the machining (101) in step a) is carried out by applying at least one machining process, preferably by turning and / or milling. Method (100) according to one of the preceding claims, characterized in that, in addition, preferably before step a) and / or before step b) and / or before step c), at least the following step is carried out: • introducing the blank (1) formed from solid material and / or the first and / or second partial section into the interior (14.1) of a processing chamber (14), • Creating an inert gas atmosphere in the interior (14.1) of the processing chamber (14), wherein in particular the oxygen content in the inert gas atmosphere is 100 ppm or less and / or the water content in the inert gas atmosphere is 100 ppm or less. Method (100) according to one of the preceding claims, characterized in that the impeller (10) has a diameter of at least 400 mm and / or an axial extent of at least 150 mm. Method (100) according to one of the preceding claims, characterized in that step c) is performed multiple times and at least one material layer (13) of at least one rotor blade (12) has a smaller layer width (T) than the previously applied material layer (13) of the same rotor blade (12). Impeller (10) comprising a base body (11) and at least one rotor blade (12), wherein the impeller (10) was manufactured according to a method (100) according to one of claims 1 to 16. Turbomachine comprising at least one impeller (10) according to claim 17.

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