Method for manufacturing a harmonic drive component, harmonic drive component and harmonic drive

Abstract

The invention relates to a method for manufacturing a harmonic drive component (1), wherein the harmonic drive component (1) consists of a precipitation hardening steel, the method comprising the following steps: - providing a blank, the blank having the following composition: 0.01 to 0.35 wt.-% carbon, at most 0.15 wt.-% silicon, at most 0.4 wt.-% manganese, 4.5 to 5.5 wt.-% chromium, 4.5 to 6.5 wt.-% nickel, 0.5 to 1 wt.-% molybdenum, at most 0.6 wt.-% vanadium, 2 to 2.5 wt.-% aluminum, at most 0.008 wt.-% sulfur, at most 0.02 wt.-% phosphor, at most 0.025 wt.-% titanium, 0.005 to 0.015 wt.-% nitrogen, at most 0.007 wt.-% oxygen, at most 0.0035 wt.-% potassium, at most 0.015 wt.-% magnesium, and the remainder iron with unavoidable trace elements; - solution annealing the blank, wherein the solution annealing is carried out by heating the blank to a solution annealing temperature between 950 °C and 1050 °C or during a forging process at a temperature between 1000 °C and 1200 °C until the precipitation hardening components of the composition are dissolved; - cooling the blank to room temperature; - machining the blank to constitute the harmonic drive component (1); and - precipitation hardening the harmonic drive component (1) at a temperature between 450 °C and 650 °C for at least 30 minutes and at most 10 hours. Furthermore, the invention relates to a harmonic drive component (1) and to a harmonic drive (2).

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for producing a harmonic drive component. Furthermore, the present invention relates to a harmonic drive component and to a harmonic drive. BACKGROUND

[0002] From DE 10 2016 219 076 A1 a harmonic drive is derived, which has a flexible, with an external toothing, drive component and a further, with an internal toothing, drive component, which engages therewith. The further drive component has a cylindrical, with an internal toothing, itself rigid sleeve section and connected thereto a disc-shaped, elastically deformable base section. The flange sleeve of such a harmonic drive is manufactured for example from a quenched and tempered steel in the strength range of 1100-1300 MPa. The ring gear is composed for example of an austenitic cast iron with a strength of 900 MPa to 1200 MPa. The production of the austenitic cast and the steel component usually consists of an effective heat treatment, i.e. hardening (martensite or bainite) and subsequent tempering (quenching and tempering) to the desired target strength. Subsequently, the component geometry of the quenched and tempered component is constituted by means of conventional production techniques, i.e. turning, drilling, milling, in particular hobbing, power skiving or also gear shaping or gear broaching. The thus manufactured component reaches a strength of up to 400 HV.

[0003] JP 2 595 609 B2 discloses a free-cutting steel, which is manufacturable by means of carburizing hardening. The steel contains by weight: one or more types of 0.10 to 0.30% of carbon (C), less than or equal to 1.0% of silicon (Si), less than or equal to 3.0% of manganese (Mn), less than or equal to 8.0% of chromium (Cr), less than or equal to 5.0% of nickel (Ni), less than or equal to 6.0% of molybdenum (Mo) and less than or equal to 2.0% of aluminum (Al). Aluminum reduces the oxygen content in the steel and at the same time improves the nitriding ability. JP 2 595 609 B2 considers the use of 0.005% of Al to be advantageous. The higher the Al share, the more strongly the toughness of the material is impaired. Furthermore, the steel contains by weight: 0.004 to 0.020% of boron (B), 0.005 to 0.050% of nitrogen (N) and less than or equal to 0.0015% of oxygen (O). The ratio between nitrogen and boron is 0.5 to 4.0 N / B. The total amount of elements with a high degree of nitriding, such as titanium (Ti) and zirconium (Zr), is less than or equal to 0.01%. The remainder consists of iron (Fe). In the steel, boron and nitrogen form boron nitride inclusions.

[0004] JP 2 805 845 B2 discloses a steel comprising by weight: 0.10 to 0.30 % by weight of carbon (C), one or more types of less than or equal to 3.0 % of manganese (Mn), less than or equal to 8.0 % of chromium (Cr), less than or equal to 5.0 % of nickel (Ni), less than or equal to 6.0 % of molybdenum (Mo) and less than or equal to 2.0 % of aluminum (Al), and 0.004 to 0.020 % of boron (B) and 0.005 to 0.050 % of nitrogen (N), wherein the ratio between nitrogen and boron is 0.5 to 0.4 N / B. Furthermore the steel consists of less than or equal to 0.0015 % of oxygen (O), less than or equal to 0.10 % of silicon (Si) and less than or equal to 0.015 % of phosphorus (P). The total amount of elements with a high degree of nitriding, such as titanium (Ti) and zirconium (Zr), is less than or equal to 0.01 %. The remainder consists of iron (Fe). If desired, in addition one or both of the elements niobium (Nb) and vanadium (V) and one or more types of calcium (Ca), lead (Pb), sulfur (S), bismuth (Bi) and tellurium (Te) are added in an optimized amount. SUMMARY

[0005] The object of the present invention is to develop a method for manufacturing a harmonic drive member, a harmonic drive member and a harmonic drive.

[0006] The object is achieved by a method for manufacturing a harmonic drive member having the features of claim 1, by a harmonic drive member having the features of claim 4 and by a harmonic drive having the features of claim 10. Preferred or advantageous embodiments of the present invention result from the dependent claims, the following description and the drawings.

[0007] In the method for manufacturing a harmonic drive member according to the present invention, the harmonic drive member consists of a precipitation hardening steel, the method comprising the following steps:

[0008] - providing a blank having the following composition: 0.01 to 0.35 % by weight of carbon, at most 0.15 % by weight of silicon, at most 0.4 % by weight of manganese, 4.5 to 5.5 % by weight of chromium, 4.5 to 6.5 % by weight of nickel, 0.5 to 1 % by weight of molybdenum, at most 0.6 % by weight of vanadium, 2 to 2.5 % by weight of aluminum, at most 0.008 % by weight of sulfur, at most 0.02 % by weight of phosphorus, at most 0.025 % by weight of titanium, 0.005 to 0.015 % by weight of nitrogen, at most 0.007 % by weight of oxygen, at most 0.0035 % by weight of potassium, at most 0.015 % by weight of magnesium, and the remainder iron with unavoidable trace elements;

[0009] - solution annealing of the blank, wherein the solution annealing is carried out by heating the blank to a solution annealing temperature of between 950 °C and 1050 °C or during a forging process at a temperature of between 1000 °C and 1200 °C until the precipitated hardening constituents of the components are dissolved;

[0010] - cooling the blank to room temperature such that the blank has a substantially martensitic structure;

[0011] - mechanical machining of the blank to constitute a harmonic drive component; and

[0012] - precipitation hardening of the harmonic drive component at a temperature of 450 °C to 650 °C for at least 30 minutes and at most 10 hours.

[0013] The blank constitutes a precipitation hardening steel and can exist as a rolled strip steel before it is heat treated. The blank can be manufactured in a cut or forged manner. In particular, the blank can be formed in an annular shape by forging or the like. The precipitation hardening steel is a steel whose hardness can be set by means of precipitated hardness in correlation with the method parameters or alloying constituents. The blank can in principle be provided in any state of machining for the heat treatment, for example in a substantially unprocessed state, wherein the entire or at least a substantial portion of the mechanical machining of the geometry of at least the near final contour of the harmonic drive component is carried out after the solution annealing and the cooling of the blank to room temperature. Alternatively, the blank can also already constitute a substantially near final contour, wherein only the final machining of the blank is carried out after the solution annealing and the cooling of the blank in order to, for example, remove warping and to machine the harmonic drive component to its final dimensions.

[0014] The alloying constituents of the blank or of the harmonic drive component manufactured therefrom have 0.01 to 0.35 % by weight of carbon (C), 0 to 0.15 % by weight of silicon (Si), 0 to 0.4 % by weight of manganese (Mn), 4.5 to 5.5 % by weight of chromium (Cr), 4.5 to 6.5 % by weight of nickel (Ni), 0.5 to 1 % by weight of molybdenum (Mo), 0 to 0.6 % by weight of vanadium (V), 2 to 2.5 % by weight of aluminum (Al), 0 to 0.008 % by weight of sulfur (S), 0 to 0.02 % by weight of phosphorus (P), 0 to 0.025 % by weight of titanium (Ti), 0.005 to 0.015 % by weight of nitrogen (N), 0 to 0.007 % by weight of oxygen (O), 0 to 0.0035 % by weight of potassium (K), 0 to 0.015 % by weight of magnesium (Mg) and the remainder iron (Fe) and unavoidable trace elements. The trace elements are impurities which are present in the material, inter alia, in connection with the manufacture. This can be, for example, copper (Cu), antimony (Sb), tin (Sn), arsenic (As) or the like.

[0015] The material has a high alloy content of elements that promote hardenability, such as chromium and nickel. In particular, significantly higher proportions of aluminum according to the invention between 2 and 2.5% by weight compared to JP 2 595 609 B2 and JP 2 805 845 B2 are dissolved on solid solution annealing, however, do not react during cooling. This takes place at higher temperatures and with a longer duration of the treatment, however, not in the manufacturing method according to the invention presented here.

[0016] In the solid solution annealing, precipitates present in the structure of the blank, in particular carbide precipitates, and other phases in the mixed crystal are dissolved, wherein the re-precipitation of the structure is prevented by cooling the blank to room temperature. The blank is cooled to room temperature at such a cooling rate that a structure essentially of martensite is present. Furthermore, the solid solution annealing serves for recrystallization of the structure region of cold deformation and thus for the elimination of cold work hardening. The blank is held in the range of 950°C to 1050°C after the rapid heating, for example, in relation to the component size. The solid solution annealing is carried out, in particular, to the dissolution of the precipitation-hardening components of the composition. The time at which this is present in relation to the alloy composition can be determined in advance by generally known simulation methods. The temperature selected for the solid solution annealing is preferably selected to be high, so that no undesired coarse particles remain in the structure, which are disadvantageous for the mechanical properties of the material. On the other hand, the temperature for the solid solution annealing is selected to be low, so that the eutectic temperature of the alloy is not exceeded, in order to prevent segregation. The preferred time for the solid solution annealing is not less than 30 minutes and not more than 90 minutes. Ideally, the precipitation-hardening components are present after approximately 45 minutes in such a way that they are completely dissolved in the matrix.

[0017] Alternatively to the heat treatment described above, a state of the blank can be achieved in which the precipitation-hardening components of the composition are dissolved, wherein the blank is processed by means of forging, more precisely advantageously at temperatures between 1000°C and 1200°C. During the forging, the mentioned precipitates or phase dissolution takes place, so that the blank is present in the state of the solid solution annealing after the forging and the cooling to room temperature.

[0018] The subsequent cooling of the blank to room temperature can in principle take place arbitrarily. In any case, the blank has a substantially martensitic basic structure after cooling. The hardenability of the material after the solution annealing or after the forging is high, so that the cooling rate does not have a significant influence on the existence of the substantially martensitic basic structure after cooling, in which almost the same hardness is always achieved, even if it is short-term, medium-term or long-term. The blank with the mentioned steel composition is an air hardenable steel, which can also be cooled in air in order to achieve the desired material properties, in particular the required hardness and / or strength. The steel thus has no significant sensitivity with respect to the cooling curve during cooling. In order to accelerate the process of the heat treatment, a martensitic hardening can alternatively be carried out after the solution annealing, in which the blank is quenched from the solution annealing temperature to room temperature in a suitable medium. Thereby, the manufacturing method is accelerated. Room temperature is understood in the context of the present invention to be an ambient temperature of between 10°C and 40°C, preferably between 15°C and 25°C.

[0019] As soon as the blank is cooled to room temperature, it can be machined, so that the geometry of the harmonic drive component exists substantially close to the final contour. In other words, the blank is processed to its final dimensions by suitable machining steps. Machining is understood, for example, to be a production or machining method of chip removal, such as milling, turning, drilling, sawing and honing. In particular, during machining, a toothing can be produced at the harmonic drive component, which can be an internal toothing or an external toothing. Thus, the blank can be processed in a soft, i.e. solution annealed, state into the final dimensions of the harmonic drive component by means of conventional techniques.

[0020] During the initial cooling of the blank, a substantially martensitic basic structure is produced, which is subsequently subjected to a precipitation hardening. Thus, the precipitation hardening, also called hardening, is carried out after machining, which substantially serves to increase the strength, in particular the yield strength, of the harmonic drive component. Here, a fine-distributed, intermetallic phase precipitation is carried out, which impedes the dislocation movement within the crystal lattice due to deformation or plastic deformation by intrinsic stresses. The precipitation hardening is advantageously carried out at a temperature of between 450°C and 650°C for at least 30 minutes and at most 10 hours. Short times and high temperatures are particularly meaningful in order to be able to increase the hardness quickly. If a complete hardenability is not desired, but only a part of the possible hardenability should be achieved, lower hardnesses and longer aging times can be used. During the precipitation hardening, the formation of nanoscale nickel aluminide occurs, which leads to an increase in the hardenability and, unlike in the case of conventional precipitation hardening steels, by precipitated carbides.

[0021] The advantage of the precipitation hardening within the scope of the method presented here is primarily that the harmonic drive component has no or only minimal configuration or volume changes during the precipitation hardening. The final component strength of the harmonic drive component is set by the precipitation hardening. A further advantage of the method is that, in comparison to conventional precipitation-hardened steels, no rapid cooling after the forging or solution annealing is necessary, whereby the warping in the blank is significantly reduced.

[0022] Preferably, the blank is solution annealed and subsequently cooled until it has a hardness of between 350 HV5 and 500 HV5. In other words, the blank has a hardness of between 350 HV5 and 500 HV5 after the solution annealing and cooling. The hardness is here first of all based essentially on the hardening potential due to the carbon content, which is less than 0.2% by weight up to approximately 0.3% by weight, so that a hardness range of between 350 HV5 and 500 HV5 is achieved. The hardness is measured at room temperature after the cooling. A hardness of 350 HV (Vickers hardness) corresponds to a Rockwell hardness of approximately 35.5 HRC and a Vickers hardness of 500 HV corresponds to a Rockwell hardness of approximately 49.1 HRC. The blank is thus solution annealed until it has a Rockwell hardness of between 35.5 HRC and 49.1 HRC. The hardness values are determined by means of a Vickers hardness test, which is used for testing homogeneous materials and is also suitable for hardness testing of thin-walled or case-hardened workpieces or edge regions. The test method is specified in the standard according to DIN EN ISO 6507-1 :2018 to -4:2018. 5 kilopounds as test force is suitable for determining the hardness. However, other test forces can also be used.

[0023] The hardness of the harmonic drive component is increased by approximately 150 HV to 250 HV only by means of the additional tempering treatment by means of the precipitation hardening. In this sense, the harmonic drive component has a hardness of between 550 HV5 and 750 HV5 after the precipitation hardening. A Vickers hardness of 550 HV corresponds to a Rockwell hardness of approximately 52.3 HRC and a Vickers hardness of 750 HV corresponds to a Rockwell hardness of approximately 62.2 HRC. The harmonic drive component is thus precipitation hardened until it has a hardness of between 52.3 HRC and 62.2 HRC.

[0024] After the precipitation hardening, the harmonic drive component preferably has a strength of at least 1600 MPa. This can be set in particular by adjusting the carbon content in the components. For example, with a carbon content of approximately 0.05% by weight, a maximum strength of approximately 1650 MPa can be achieved, with a carbon content of approximately 0.18% by weight, a strength of approximately 1850 MPa can be achieved, and with a carbon content of approximately 0.28% by weight, a strength of more than 1900 MPa can be achieved.

[0025] The harmonic drive component according to the application has a precipitation hardening steel with the following components: 0.01 to 0.35% by weight of carbon, at most 0.15% by weight of silicon, at most 0.4% by weight of manganese, 4.5 to 5.5% by weight of chromium, 4.5 to 6.5% by weight of nickel, 0.5 to 1% by weight of molybdenum, at most 0.6% by weight of vanadium, 2 to 2.5% by weight of aluminum, at most 0.008% by weight of sulfur, at most 0.02% by weight of phosphorus, at most 0.025% by weight of titanium, 0.005 to 0.015% by weight of nitrogen, at most 0.007% by weight of oxygen, at most 0.0035% by weight of potassium, at most 0.015% by weight of magnesium, and the remainder iron with unavoidable trace elements.

[0026] Preferably, the harmonic drive component has carbides of the type M6C and / or MC. The carbides form during the precipitation hardening. An example of a carbide of the type M6C is chromium carbide in the form of Cr6C, an example of a carbide of the type MC is vanadium carbide in the form of VC.

[0027] Preferably, the harmonic drive component has precipitations of nickel aluminide with a size of at most 100 nm. Such precipitations have the composition NiAl and show good material properties for the harmonic drive component. According to the mentioned precipitations, the strength of the harmonic drive component is increased by approximately 200 HV to 250 HV compared to the solid solution annealed state.

[0028] The harmonic drive according to the application comprises a harmonic drive component according to the second aspect of the application. The harmonic drive comprises, for example, a locally radially deformable flexible flange sleeve with an external toothing and a rigid gear ring with an internal toothing, which are surrounded by a wave generator with a non-circular outer circumferential surface, wherein the external toothing of the flange sleeve meshes at least partially with the internal toothing of the gear ring for the transmission of torque to at least one toothed joint area. The harmonic drive component can be the gear ring of the harmonic drive. Alternatively or additionally, the harmonic drive component can also be the flange sleeve of the harmonic drive.

[0029] The above-mentioned embodiments of the method apply equally to the harmonic drive component according to the application and the harmonic drive according to the application and vice versa. BRIEF DESCRIPTION OF DRAWINGS

[0030] Further measures to improve the application are shown in detail below together with a description of preferred embodiments of the application according to the drawings. In the drawings, identical or similar elements are provided with the same reference signs. Herein are shown:

[0031] Figure 1 A schematic cross-sectional view of a harmonic drive component according to the application according to the first embodiment is shown, wherein the harmonic drive component is designed as a gear ring,

[0032] Figure 2 a schematic cross-sectional view of a harmonic drive component according to the present application according to a second embodiment, wherein the harmonic drive component is configured as a flange sleeve, and

[0033] Figure 3 a schematic block diagram of a method according to the present application for manufacturing a harmonic drive component according to Figure 1 or Figure 2 . DETAILED DESCRIPTION

[0034] According to the drawings, the method for manufacturing a harmonic drive component 1 according to the present application is visualized according to a block diagram, the harmonic drive component according to Figure 1 as a ring gear 2 of a harmonic drive, not shown here, and according to Figure 2 as a flange sleeve 3 of a harmonic drive. In other words, the ring gear 2 according to Figure 1 and the flange sleeve 3 according to Figure 2 are understood as harmonic drive components 1. The block diagram for describing the manufacturing method is shown in Figure 3 . The ring gear 2 and / or the flange sleeve 3 are thus set up for use in a harmonic drive.

[0035] In a first method step 11, a blank, not shown here, is manufactured, wherein the blank is configured from a precipitation hardening steel as a rolled strip steel, which is formed into a ring shape by forging. The blank has the following composition: 0.01 to 0.35% by weight of carbon, at most 0.15% by weight of silicon, at most 0.4% by weight of manganese, 4.5 to 5.5% by weight of chromium, 4.5 to 6.5% by weight of nickel, 0.5 to 1% by weight of molybdenum, at most 0.6% by weight of vanadium, 2 to 2.5% by weight of aluminum, at most 0.008% by weight of sulfur, at most 0.02% by weight of phosphorus, at most 0.025% by weight of titanium, 0.005 to 0.015% by weight of nitrogen, at most 0.007% by weight of oxygen, at most 0.0035% by weight of potassium, at most 0.015% by weight of magnesium, and the remainder iron with unavoidable trace elements.

[0036] In a second method step 12, a solution annealing of the provided blank is carried out. The solution annealing can be carried out by two alternative steps. On the one hand, the solution annealing can be carried out as a separate heat treatment step, wherein the blank is heated to a solution annealing temperature between 950 °C and 1050 °C and is heat treated until precipitated hardening components of the components of the blank are dissolved. Such components are inter alia carbide precipitates and other phases of mixed crystals. On the other hand, the blank is subjected to a forging process at temperatures between 1000 °C and 1200 °C during its manufacture from a rolled strip steel, wherein the temperature is maintained until the precipitated hardening components of the components of the blank are dissolved. After the solution annealing or the forging at the solution annealing temperature, the blank has a hardness between 350 HV5 and 500 HV5.

[0037] In a third method step 13, the blank is cooled until room temperature. The cooling is carried out in air in this context, but can also be carried out in a fluid, such as water, oil or a gas.

[0038] After the cooling, the blank is subjected to a mechanical processing in a fourth method step 14, so that the harmonic drive component 1 is composed of the blank. With the example of the ring gear 2 according to Figure 1 the inner toothing 4 at the inner circumference of the ring gear 2 can be produced by chip removal machining. With the example of the flange sleeve 3 according to Figure 2 the outer toothing 5 at the outer circumference of the flange sleeve 3 can be produced by chip removal machining. In any case, the geometry of the harmonic drive component 1 in an essentially close-to-final contour is produced by means of the mechanical processing of the blank.

[0039] The harmonic drive component 1 is precipitation hardened after its machining in a fifth method step 15 at a temperature of 450 °C to 650 °C and for at least 30 minutes and at most 10 hours. By the hardening chromium carbide of the type Cr6C as well as vanadium carbide (VC) are formed in the structure of the harmonic drive component 1. In addition, nickel aluminide precipitates of a size of up to 100 nm are formed. By the precipitates or carbides the hardness within the structure is increased by 200 HV to 250 HV, so that the harmonic drive component 1 after the precipitation hardening has a hardness of between 550 HV5 and 750 HV5 and a strength of at least 1600 MPa. Thus, after the precipitation hardening there is a harmonic drive component 1 of a precipitation hardened steel with the following composition: 0.01 to 0.35 wt.-% carbon, at most 0.15 wt.-% silicon, at most 0.4 wt.-% manganese, 4.5 to 5.5 wt.-% chromium, 4.5 to 6.5 wt.-% nickel, 0.5 to 1 wt.-% molybdenum, at most 0.6 wt.-% vanadium, 2 to 2.5 wt.-% aluminum, at most 0.008 wt.-% sulfur, at most 0.02 wt.-% phosphorus, at most 0.025 wt.-% titanium, 0.005 to 0.015 wt.-% nitrogen, at most 0.007 wt.-% oxygen, at most 0.0035 wt.-% potassium, at most 0.015 wt.-% magnesium, and the rest iron with unavoidable trace elements, such as copper, antimony, tin, arsenic, etc.

[0040] Legend of the figures

[0041] 1 harmonic drive component

[0042] 2 ring gear

[0043] 3 flange sleeve

[0044] 4 inner tooth portion

[0045] 5 outer tooth portion

[0046] 11 first method step

[0047] 12 second method step

[0048] 13 third method step

[0049] 14 fourth method step

[0050] 15 fifth method step

Claims

1. A method for manufacturing a harmonic drive member (1), wherein the harmonic drive member (1) consists of a precipitation hardening steel, the method comprising the steps of: - providing a blank having the following composition: 0.01 to 0.35 wt.% carbon, at most 0.15 wt.% silicon, at most 0.4 wt.% manganese, 4.5 to 5.5 wt.% chromium, 4.5 to 6.5 wt.% nickel, 0.5 to 1 wt.% molybdenum, at most 0.6 wt.% vanadium, 2 to 2.5 wt.% aluminum, at most 0.008 wt.% sulfur, at most 0.02 wt.% phosphorus, at most 0.025 wt.% titanium, 0.005 to 0.015 wt.% nitrogen, at most 0.007 wt.% oxygen, at most 0.0035 wt.% potassium, at most 0.015 wt.% magnesium, and the remainder iron with unavoidable trace elements; - solution annealing the blank, wherein the solution annealing is performed by heating the blank to a solution annealing temperature between 950 °C and 1050 °C or during a forging process at a temperature between 1000 °C and 1200 °C, until the precipitation hardenable components of the composition are dissolved; - cooling the blank to room temperature such that the blank has a martensitic structure; - machining the blank to constitute the harmonic drive member (1); and - precipitation hardening the harmonic drive member (1) at a temperature between 450 °C and 650 °C for at least 30 minutes and at most 10 hours.

2. The method according to claim 1, characterized in that the blank has a hardness between 350 HV5 and 500 HV5 after solution annealing and cooling.

3. The method according to any one of the preceding claims, characterized in that the harmonic drive member (1) has a hardness between 550 HV5 and 750 HV5 after precipitation hardening.

4. A harmonic drive member (1) of a precipitation hardening steel having the following composition: 0.01 to 0.35 wt.% carbon, at most 0.15 wt.% silicon, at most 0.4 wt.% manganese, 4.5 to 5.5 wt.% chromium, 4.5 to 6.5 wt.% nickel, 0.5 to 1 wt.% molybdenum, at most 0.6 wt.% vanadium, 2 to 2.5 wt.% aluminum, at most 0.008 wt.% sulfur, at most 0.02 wt.% phosphorus, at most 0.025 wt.% titanium, 0.005 to 0.015 wt.% nitrogen, at most 0.007 wt.% oxygen, at most 0.0035 wt.% potassium, at most 0.015 wt.% magnesium, and the remainder iron with unavoidable trace elements.

5. The harmonic drive member (1) according to claim 4, characterized in that the harmonic drive member (1) has carbides of the type M6C and / or MC.

6. The harmonic drive member (1) according to claim 4 or 5, characterized in that the harmonic drive member (1) has precipitates of nickel aluminide with a size of at most 100 nm.

7. The harmonic drive member (1) according to claim 4 or 5, the harmonic drive member (1) has a hardness of at least 550 HV5. characterized in that The harmonic drive component (1) has a hardness between 550 HV5 and 750 HV5.

8. The harmonic drive component (1) according to claim 4 or 5, characterized in that The harmonic drive component (1) has a strength of at least 1600 MPa.

9. The harmonic drive component (1) according to claim 4 or 5, characterized in that The harmonic drive component (1) is a ring gear (2) and / or a flange sleeve (3) of a harmonic drive.

10. A harmonic drive comprising a harmonic drive component (1) according to any one of claims 4 to 9.

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