Mechanically, in particular tribologically, loaded component and method for manufacturing the component

Abstract

To provide a member that is optimized in terms of wear resistance and can be manufactured relatively easily and / or can be easily remanufactured, and that engages with particularly hot rolling material in a rolling mill. [Solution] A component that is mechanically, particularly tribologically, loaded in a rolling mill, having a main body 2 made of a basic material and at least one functional layer 3 installed on the main body 2 made of at least one material different from the basic material, wherein the material of the at least one functional layer 3 has higher wear resistance than the basic material, and the main body 2 includes at least one other outer layer as a sacrificial layer 5 that at least partially surrounds the at least one functional layer 3, and the sacrificial layer 5 is made of a material having lower wear resistance than the at least one functional layer 3.

Description

[Technical Field]

[0001] The present invention relates to a mechanically, in particular tribologically, loaded component in a rolling mill and to a method for manufacturing or remanufacturing such a component. A mechanically, in particular tribologically, loaded component in the sense of the present invention can be, for example, a slide guide, a linear guide, a guide ruler, a roller or a roll, which are in contact with the rolling material and are designed as a wear partner in terms of their material structure.

[0002] More particularly, the present invention relates to rollers that engage rolled material in a rolling mill and to methods of manufacturing or remanufacturing rollers that engage rolled material in a rolling mill, particularly a hot rolling mill. [Background technology]

[0003] Such a roller is known, for example, from US Pat. No. 5,629,499. The disclosure relates to a roller body for conveying continuously cast steel strand in a roller conveyor or continuous casting machine, comprising a roller jacket made of a base material and a wear layer covering the roller jacket surface, the wear layer being applied by build-up welding to the base material with a welding filler metal, the base material of the roller jacket being steel. The application is performed as a single-layer weld. Remanufacturing of the roller after wear is performed by preparing the roller material as a rotating part and applying a single-layer weld build-up to the base material with a predetermined minimum thickness. The weld layer is then returned to the closed, single-sided roller jacket surface while maintaining the minimum thickness of the wear layer.

[0004] During operation, mechanical components are often subjected to loads that vary locally and do not act uniformly on the component. In particular, the differences between the center and the edges of the component should be frequently monitored. In mainly cylindrical components such as disks, shafts or rollers, and other components with flat surfaces, the center requires high ductility under small loads, while the boundary areas close to the surface are subjected to, for example, large mechanical, thermal and / or corrosion loads.

[0005] For this reason, it is generally known to provide rollers with coatings that perform different functions, such as improved wear resistance, improved bending or torsional rigidity under static, dynamic or vibration loads, improved heat resistance, a defined thermal expansion or thermal conductivity and improved corrosion resistance, as described, for example, in US Pat. No. 5,649,499.

[0006] As mentioned above, it is known to apply such functional layers by overlay welding, thermal spraying, vapor deposition, dusting, electroplating or casting. In many cases, a certain surface quality is required for such components, i.e., a certain roughness and undulations, which does not necessarily exist after the application of the functional layer, but rather has to be achieved by suitable reworking, such as turning, milling or grinding.

[0007] In components where improved wear resistance is to be promoted by providing so-called functional layers, the production of the desired surface by post-processing is necessarily relatively time-consuming, since wear-resistant materials resist post-processing more strongly than less wear-resistant materials. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2009 / 130079 Summary of the Invention [Problem to be solved by the invention]

[0009] The problem underlying the present invention is to provide a component for engaging the particularly hot rolled material in a rolling mill, which is optimized in terms of wear resistance and which can be manufactured relatively easily and / or easily remanufactured.

[0010] Furthermore, the problem underlying the present invention is to provide a corresponding method for manufacturing and / or remanufacturing such components. [Means for solving the problem]

[0011] This problem is solved by the features of claims 1 and 8. Advantageous configurations of the invention are evident from the dependent claims.

[0012] According to one aspect of the present invention, a mechanically, in particular tribologically, loaded component is provided, having a main body made of a basic material and at least one functional layer attached to the main body, the material of the at least one functional layer having a higher wear resistance than the basic material, and the main body including at least one further outer layer as a sacrificial layer at least partially surrounding the at least one functional layer, the sacrificial layer being made of a material having a lower wear resistance than the at least one functional layer.

[0013] Mechanically loaded elements within the meaning of the present invention are elements which engage with the rolled material, for example as wear partners, or which are designed to guide the rolled material. However, the term elements within the meaning of the present invention also includes, but is not limited to, sliding guides, guide rulers, rollers or rolls, for example support rolls which cooperate with other rolls, for example in roller conveyors.

[0014] Preferably, at least one functional layer is constructed from a material that is relatively harder and / or more wear resistant than the sacrificial layer.

[0015] According to another aspect of the present invention, a roller for engaging a hot rolling material in a rolling mill is provided as a component within the meaning of the present invention, the roller having a roller body including a roller jacket made of a basic material and at least one functional layer made of a material different from the basic material, the material of the at least one functional layer having a higher wear resistance than the basic material, and the roller body including at least one outer layer as a sacrificial layer, which at least partially surrounds the at least one sacrificial layer, and which is made of a material having a lower wear resistance than the at least one functional layer.

[0016] Rollers engaging the hot rolled stock within the meaning of the present invention are roller conveyor rollers, rolls of a rolling mill, rolls of a continuous caster, continuous casting guides or rolls of other equipment provided for supporting, handling and / or transporting the hot rolled stock.

[0017] The roller body and / or the roller jacket can be, for example, essentially cylindrical, and the roller jacket surface can also be conical or cambered. The roller jacket body can comprise multiple layers that can form a composite with appropriate material properties. At least one outer layer of the roller jacket is configured as a so-called functional layer, i.e., the material of the functional layer has the desired properties for engagement with the rolled material, such as wear resistance, heat resistance, hardness, or ductility.

[0018] A functional layer in the sense of the present invention may be understood as a wear protection layer made of a material that is wear-resistant with respect to the base material of the roller body and / or with respect to the other layers of the roller.

[0019] Preferably, the sacrificial layer does not have all the requirements for engagement with the rolled material, in particular it has a lower wear resistance, but it is nevertheless able to meet the desired application-specific properties in terms of surface quality (roughness, relief and dimensional accuracy).

[0020] Basically, the roller jacket is configured to include one or more supplementary layers arranged under at least one functional layer, which can perform various functions, such as separating two hard and brittle layers to prevent cracking or separating two layers of different hardness to prevent weakening, but also functioning as a sacrificial layer, among others.

[0021] The supplemental layer may, for example, have a lower strength and a higher ductility than the other layers, thus allowing for stress reduction and crack prevention in the boundary area relative to the harder and more wear-resistant functional layer.

[0022] The term sacrificial layer is intended to mean that the partial layer in question does not have the properties required for application, for example in a rolling mill, and that a partial layer or part of the entire layer is intentionally placed in order to provide particularly advantageous properties to the layer area located below it, or in general to facilitate its effective use that is optimal for the application.

[0023] A sacrificial layer can be applied, for example, over a hard layer and can form the outermost jacket surface of the roller, and can be processed to provide a desired surface quality, for example a predetermined surface roughness.

[0024] The sacrificial layer can completely or partially surround the outermost functional layer. It is advantageous if the roller further comprises a mechanically post-machined soft layer on top of the hard layer. In this way, it is easier to achieve a good surface quality during coating. Furthermore, mechanical machining of the sacrificial layer is inherently easier. The sacrificial layer can be post-machined to a nominal diameter using easier and less expensive methods, such as by turning or reverse turning. Finally, the tools used for this purpose are cheaper and easier to handle. The softer layer can be optimally tailored to the application, leaving the beneficial hard or functional layer completely or almost completely intact. The thickness of the softer layer can be freely selected within wide limits and thus adapted to the requirements of the overall system. Maintaining the functional layer is an aspect of the present invention, especially when the functional layer has a property gradient that allows the best properties to be obtained directly at the surface.

[0025] This also allows for greater freedom in the design of the hard layer, which in preferred embodiments is a single layer with a structural and / or property gradient, or multiple layers with structural and property gradients from layer to layer, or multiple layers with structural and property gradients from layer to layer and within layers. If removal of, for example, 200-500 micrometers must be performed after coating, complex optimization of the alloy composition and process parameters in order to achieve optimal properties in the edge region, such as high strength and good corrosion resistance, is often pointless. For example, sophisticated modern coating concepts, in which the proportion of hard external phases such as tungsten carbide or titanium carbide increases continuously (within a layer) or discontinuously (from layer to layer), or both, cannot be used in this case, or can only be used to a limited extent.

[0026] The drawbacks of the prior art are overcome by the application of a preferably softer sacrificial or cover layer that is partially or almost completely removed during mechanical processing. Any remaining soft layer residues are quickly removed during industrial use due to their low wear resistance and do not impair the functionality of the layer. The hard layer remains intact and can be used exactly as originally intended. This allows the property profile, which correlates with the macroscopic and microscopic structure of the layer, to be set (adjusted) according to specifications or as desired. Because the hard layer is not processed, any non-exactly uniform thickness progressions, for example, across the length and width or in the axial and tangential directions, are equalized during operation by the resulting mechanical loads.

[0027] The optimum combination of installation and subsequent partial removal of the entire layer contributes, on the one hand, to particularly advantageous technical properties and, on the other hand, to maximized product economy.

[0028] Preferably, at least one functional layer is made of a material that is relatively harder and / or more wear resistant than the sacrificial layer.

[0029] The functional layer may have a radially extending structural and / or property gradient, for example in a rotationally symmetrical element such as a roller, for example, the functional layer may have a hardness gradient from the inside to the outside, for example from softer to harder.

[0030] The functional layer can comprise, for example, steel containing a predetermined proportion of a hard external phase, such as tungsten carbide or titanium carbide. The external phase can be distributed continuously in one layer so that a hardness gradient is achieved. Such a hardness gradient can be easily achieved when a hard functional layer in the sense of the present invention forms a jacket surface of a component or, for example, a roller jacket of a roller together with a cover layer that is softer than the sacrificial layer. The sacrificial layer makes it possible to maintain the set gradient.

[0031] As a material for the body of the component, almost all common steel grades are worthy of consideration, for example, construction steel such as S5355J or heat treatable steel such as 25CrMo4.

[0032] As materials for at least one functional layer, wear-resistant hot-work steels (hot work tool steels) such as 1.2344 or high-speed steels such as 1.3344 are suitable. Furthermore, martensitic stainless steels based on 1.4057, nickel-based alloys such as Inconel 625 and Inconel 718, or cobalt-based alloys such as Stellite 6 and Stellite 21 are also suitable. In particular, wear-resistant layers further contain hard phases such as tungsten carbide and / or titanium carbide. The volume fraction of the hard phases can, in extreme cases, exceed the volume fraction of the matrix.

[0033] In a preferred embodiment of the member or roller according to the invention, several functional layers with different properties and / or made of different materials are provided.

[0034] The multiple functional layers may, for example, form a radial structural gradient and / or a property gradient in the roller jacket.

[0035] In a preferred embodiment of the component according to the invention, the jacket surface of the component is configured as a single jacket surface, i.e., the jacket surface does not have any steps or diameter changes. As already mentioned above, the jacket surface of the roller component can be cylindrical, conical, cambered or S-shaped.

[0036] Another aspect of the invention relates to a method for manufacturing or remanufacturing a mechanically, in particular tribologically, loaded component according to any one of claims 1 to 8, which has a body made of a base material and at least one functional layer applied to the body, the functional layer comprising at least one material different from the base material, said method comprising the following method steps: - providing a body portion made of a base material; - providing at least one wear-resistant functional layer on the body; - placing an outer sacrificial layer on the functional layer, the sacrificial layer being made of a material that differs in terms of material properties from the material properties of the functional layer and has a lower wear resistance than at least one functional layer; - post-processing the body by removing material to form a jacket surface having predetermined dimensions, which is closed at least in the area of ​​the functional surface; Includes.

[0037] The method steps are preferably performed in the order in which they are listed.

[0038] The application of at least one functional layer and / or sacrificial layer is preferably selected from the group of methods comprising overlay welding, thermal spraying, plasma coating, casting, centrifugal casting, vapor deposition, dusting, electroplating, chemical coating.

[0039] Post-processing can be carried out, for example, by turning and / or milling and / or grinding.

[0040] The thickness of the at least one functional layer and / or the sacrificial layer can be selected such that the sacrificial layer at least partially surrounds the at least one functional layer after material removal.

[0041] For example, the jacket surface can be formed as a single jacket surface.

[0042] In one aspect of the method, multiple functional layers having different properties and / or made of different materials can be applied such that the multiple functional layers form a structural gradient and / or a property gradient.

[0043] Another aspect of the present invention relates to a method for manufacturing or remanufacturing a roller for engaging hot rolled material in a rolling mill, in particular a method for manufacturing or remanufacturing a roller having a roller body including a body made of a base material and at least one material different from the base material, the method comprising the following processing steps: - providing a roller body having a roller jacket made of a base material; - providing at least one wear-resistant functional layer on the roller body; - placing an outer sacrificial layer on the functional layer, the sacrificial layer being made of a material that differs in terms of material properties from the material properties of the functional layer and has a lower wear resistance than at least one functional layer; - post-processing the roller jacket by reducing its diameter to a closed jacket surface having predetermined dimensions; Includes.

[0044] The method steps are preferably performed in the order in which they are listed.

[0045] The application of the at least one functional and / or sacrificial layer can be carried out, for example, by welding overlay, thermal spraying, casting, vapor deposition, plasma coating, centrifugal casting, dusting, electroplating or chemical coating.

[0046] The method according to the invention may further comprise using heat supplied during application of the sacrificial layer to influence the ductility of the functional layer underlying the sacrificial layer, the functional layer being subjected to a tempering process by the sacrificial layer.

[0047] Post-processing can be carried out by turning and / or milling and / or grinding.

[0048] Preferably, the thickness of the at least one functional layer and / or the sacrificial layer is selected such that the sacrificial layer at least partially surrounds the at least one functional layer after diameter reduction of the roller jacket.

[0049] Preferably, the roller jacket surface is configured as a single-sided jacket surface, which may be, for example, completely closed.

[0050] In the method according to the invention, multiple functional layers with different properties and / or made of different materials can be arranged so that they form a preferably radial structural and / or property gradient of the roller jacket. The above-mentioned layers with suitable properties can be adapted to the different loads acting on the roller jacket at different times, so that the best roller jacket properties for each external load are present in accordance with the arrangement of the layers on the roller.

[0051] The wear resistance and / or load capacity of the rollers according to the present invention can be, for example, practically optimized, and methods for practical optimization may include detecting tribological data during the manufacture and / or remanufacturing of at least one roller, detecting wear and / or load data resulting from use in operation of the roller, correlating the tribological data from the manufacture and / or remanufacturing of the roller with wear and / or load data based on operation of an electronic database, automatically setting and / or changing the structure of the roller jacket to load and / or automatically changing the load due to operation of the roller.

[0052] Optimization of the wear resistance and / or load bearing capacity of a component or roller can also be performed using data relating to material removal during operation and / or remanufacturing of the component, for example.

[0053] The tribological data is preferably measurement data selected from a group of measurement data including torque, cutting force, feed force, friction force, friction coefficient and temperature during cutting of the member or roller jacket, and surface roughness of the roller jacket surface immediately after cutting of the roller jacket.

[0054] Tribological data can be detected with respect to the roller geometry, both in position and in time.

[0055] The wear and / or load data based on the operation of the roller is preferably measured data that is recorded intermittently on the roller during operation or detected online during operation.

[0056] The wear data may include measured surface characteristics selected from the group of measurement data on roughness, undulation, profile, surface hardness, coefficient of friction of the roller jacket surface, and structure of wear signatures on the roller jacket surface.

[0057] It is also possible to consider the cutting process with geometrically defined and undefined cutting edges as a tribometer, so that the detection of material removal and associated quantities such as surface quality, shape and position of the surfaces can be taken into account for optimizing the wear resistance and / or load-bearing capacity of the component.

[0058] The load data can be selected from a group of data including point loads acting on the rollers, distributed loads, surface pressure, rotational speed, roller slippage, and the temperature and / or properties of the rolled material and / or the medium used in cooling the rolled material.

[0059] The method may involve the automatic analysis of the corrected data with the aid of at least one expert system and / or using machine learning techniques, in particular artificial neural networks, deep artificial neural networks, decision tree-based methods, decision trees, ensemble methods based on linear or non-linear regression models with or without regularization, support vector machines with linear, polynomial or other kernel functions or the like.

[0060] The invention will now be described with reference to an embodiment shown in the drawings. [Brief explanation of the drawings]

[0061] [Figure 1] 1 is a schematic partial cross-sectional view of a roller formed in accordance with the prior art; [Figure 2A] 2A-2C are diagrams illustrating various stages in the processing of the roller illustrated in FIG. 1. [Figure 2B] 2A-2C are diagrams illustrating various stages in the processing of the roller illustrated in FIG. 1. [Figure 3A] 1A and 1B are diagrams showing a schematic partial cross-sectional view of a method for manufacturing or remanufacturing a roller according to the present invention; [Figure 3B] 1A and 1B are diagrams showing a schematic partial cross-sectional view of a method for manufacturing or remanufacturing a roller according to the present invention; [Figure 3C] 1A and 1B are diagrams showing a schematic partial cross-sectional view of a method for manufacturing or remanufacturing a roller according to the present invention; [Figure 4] 1 is a partial cross-sectional view of a roller according to the present invention after a predetermined period of operation. [Figure 5] 1 shows a schematic representation of a multi-layer system of rollers according to the invention; DETAILED DESCRIPTION OF THE INVENTION

[0062] 1 and 2, which show several partial cross-sectional views of a prior art roller in different manufacturing states. The reference numerals used in relation to Figures 1 and 2 are likewise used for the roller according to the invention shown in Figures 3 to 5.

[0063] The roller 1 shown in Figures 1 and 2 is shown in a partial cross section, with the cross section shown above the axis of symmetry of the roller 1. The roller 1 comprises a roller body 2 made of steel as the base material and a jacket layer which comprises a so-called functional layer 3. A supplementary layer 4 can be arranged below the functional layer 3.

[0064] When a roller 1 is newly manufactured or remanufactured, a functional layer is typically applied as a wear protection layer with suitable material properties to the supplementary layer 4 or directly to the roller body 2, for example by overlay welding. After application of the functional layer 3, the roller jacket surface is mechanically reworked, i.e., typically cut to the nominal diameter of the roller 1 and appropriately ground, so that the roller jacket surface has a suitable surface texture, i.e., a surface roughness or surface flatness that meets the specifications. The state of the roller 1 after application of the functional layer 3 is shown in FIG. 2A , and the state after mechanical surface processing is shown in FIG. 2B . It can be easily understood that the reworking of the surface of the functional layer 3 requires a considerable amount of effort.

[0065] The method according to the invention and the element according to the invention, in this example a roller 1, are shown in Figures 3 to 5. As already mentioned at the beginning, elements that come into consideration are, for example but not exclusively, sliding guides in roller conveyors, guide rulers, rollers or rolls, for example support rolls which cooperate with other rolls, or elements that are mechanically loaded and subject to wear.

[0066] 3A shows the roller 1 after the application of a functional layer 3 made of a wear-resistant, hard, and / or tough material that has more advantageous wear properties than the base material of the roller body 2 or the supplementary layer 4 disposed therebetween. The supplementary layer 4 can be made of a relatively soft material, for example, based on austenitic stainless steel 1.4404. In this embodiment of the invention, the functional layer 3 applied by overlay welding is made of a wear-resistant hot work steel (hot work tool steel) such as 1.2344 or a high-speed steel such as 1.3344 with an outer phase of tungsten carbide and / or titanium carbide, which achieves adequate wear resistance for the functional layer 3.

[0067] Immediately after its attachment to the roller body 2 according to Fig. 3A, the functional layer 3 does not meet any requirements for the surface texture of the prepared component. In the next step shown in Fig. 3B, a sacrificial layer 5, for example made of the same material as the remaining supplementary layers or made of a different material, is applied to the functional layer 3, since the sacrificial layer may have a lower ductility than the supplementary layers (e.g., buffer layers) located further inwards or, unlike them, does not have to meet special requirements for heat conduction and / or thermal expansion. The sacrificial layer 5 does not meet the application-specific requirements for material wear resistance and / or hardness and / or toughness.

[0068] After the sacrificial layer 5 is applied, the roller jacket has a surplus portion which, in a further method step, is reduced to the nominal diameter of the roller 1 by suitable post-processing such as milling, grinding or turning, and finally has the desired surface roughness that meets the application-based specifications of the roller 1, as shown in Figure 3C.

[0069] Figure 4 shows a partial cross section of a roller according to the invention after some time of use or operation. Part of the sacrificial layer has been worn away by the load, and part of it is still present. Part of the functional layer 3 has also been worn away, and the wear on both layers is usually quite different. The thickness of the functional layer 3 has leveled out over time.

[0070] Figure 5 shows a multilayer system for the roller jacket, which comprises several functional layers 3 and several supplementary layers 4 arranged in such a way that a radial hardness gradient is achieved. On top of the layer arrangement consisting of the functional layers 3, a sacrificial layer 5, not shown in Figure 5, is applied. The sacrificial layer is then post-processed by suitable post-processing in relation to the surface roughness and nominal diameter of the roller, as in the example according to Figure 3. [Explanation of symbols]

[0071] 1. Laura 2 Roller body 3 Functional Layer 4 Supplementary layer 5 Sacrificial Layer

Claims

1. 1. A component that is mechanically, in particular tribologically, loaded in a rolling mill, comprising a body made of a basic material and at least one functional layer (3) arranged on the body made of at least one material different from the basic material, wherein the material of the at least one functional layer has a higher wear resistance than the basic material, and the body comprises at least one further outer layer as a sacrificial layer (5) at least partially surrounding the at least one functional layer, the sacrificial layer (5) being made of a material having a lower wear resistance than the at least one functional layer (3).

2. 2. The component according to claim 1, characterized in that the at least one functional layer (3) is made of a material that is relatively harder and / or more wear-resistant than the sacrificial layer (5).

3. 3. The element according to claim 1, characterized in that it is configured as a roller (1) for a rolling mill, in particular for a hot rolling mill.

4. 4. Component according to claim 3, characterized in that the functional layer (3) preferably has a radially extending structural and / or property gradient.

5. 5. Component according to any one of claims 1 to 4, characterized in that it is provided with several functional layers (3) with different properties and / or made of different materials.

6. 6. The element according to any one of claims 3 to 5, characterized in that the functional layers (3) preferably form a structural and / or property gradient in the radial direction of the roller jacket.

7. 7. The member according to claim 3, wherein the roller jacket surface is formed as a single jacket surface.

8. 8. A method for manufacturing or remanufacturing a mechanically, in particular tribologically, loaded component according to any one of claims 1 to 7, having a body made of a basic material and at least one functional layer (3) applied to said body, said functional layer comprising at least one material different from said basic material, comprising the following method steps: - providing a body made of a base material; - providing at least one functional layer resistant to wear on said body; - applying an outer sacrificial layer (5) to said functional layer (3), said sacrificial layer (5) being made of a material that differs in terms of material properties from those of said functional layer (3) and has a lower wear resistance than said at least one functional layer; - post-processing said body by removing material to form a jacket surface having predetermined dimensions, closed at least in the area of ​​its functional surface; A method comprising:

9. 9. A method for manufacturing or remanufacturing a roller (1) as a component, comprising post-processing the roller jacket by reducing its diameter to a closed roller jacket surface having a predetermined outer diameter.

10. 10. The method according to claim 8 or 9, characterized in that the application of the at least one functional layer (3) and / or the sacrificial layer (5) is selected from the group of methods comprising: overlay welding, thermal spraying, plasma coating, casting, centrifugal casting, vapor deposition, dusting, electroplating, chemical coating.

11. 11. The method according to claim 8, wherein the post-processing is carried out by turning and / or milling and / or grinding.

12. 12. The method according to any one of claims 8 to 11, characterized in that the thickness of the at least one functional layer (3) and / or the sacrificial layer (5) is selected so that the sacrificial layer (5) at least partially surrounds the at least one functional layer after material removal.

13. 13. A method according to any one of claims 8 to 12, characterized in that the jacket surface is produced as a single jacket surface.

14. 14. The method according to any one of claims 8 to 13, characterized in that a plurality of functional layers with different properties and / or made of different materials are applied in such a way that the plurality of functional layers (3) preferably form a radial structural gradient and / or property gradient.

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