Wear-resistant component and method for manufacturing it

Abstract

Wear-resistant component (20) comprising: a carrier material (25) consisting of a first metal; as well as a coating (27) which is arranged in contact with the substrate material (25) and covers an area (25A), wherein the covered area (25A) is part of a surface of the substrate material (25), wherein: in an edge section (29) of the coating (27) which corresponds to a boundary between the covered area (25A) and an exposed area (25B) outside the covered area (25A) on the surface of the substrate material (25), the exposed area (25B) and a surface (27A) of the coating (27) are flush with each other and form a forged surface; the coating (27) contains a matrix (95) consisting of a second metal and hard particles (91) dispersed in the matrix (95); the hard particles are located in a surface region (27B) of the coating (27) that lies within an average particle diameter of the hard particles (91) from the surface (27A) of the coating (27); and of the hard particles (91) located in the surface area (27B) of the coating (27) any hard particle (91) which has an area exposed at the surface (27A) of the coating (27) has an acute central angle (θ) corresponding to the area exposed at the surface (27A) of the coating (27).

Description

Technical field

[0001] The present invention relates to a wear-resistant component and a method for manufacturing the wear-resistant component. Technical background

[0002] Components belonging to hydraulic excavators, bulldozers, wheel loaders, and other construction equipment operating in environments containing sand and other materials include wear-resistant components, such as ripper hooks and teeth. Such a wear-resistant component may have a coating in an area where particularly high wear resistance is desired. In an available coating, hard particles are dispersed in a matrix, for example, steel. Such a coating can be formed, for example, by weld overlay (see, for example, JP 2008-000763A and JP H08-47774A).

[0003] JP H09-136 136 A describes a process for manufacturing composite components requiring wear, corrosion, and heat resistance, such as VTR drums or engine pistons. It details a process in which a substrate material is coated with a wear-resistant layer, which is then formed by die forging. This process improves the bond between the substrate material and the wear-resistant layer, thereby increasing the integrity of the composite and reducing manufacturing costs. The process focuses particularly on ensuring strong adhesion by controlling the material flow during forging.

[0004] JP 2013-046928A describes a process for manufacturing heavy-duty engine exhaust valves for large marine diesel engines, in which a Ni-Cr-Al-based precipitation-hardening alloy is applied to the parts of the valve requiring high-temperature corrosion resistance. The process involves multiple weld overlays of the alloy onto a steel substrate, followed by hot die forging to shape the valve, and the application of microstructural modifications to the welded parts. The process concludes with a solution annealing treatment and subsequent precipitation hardening to enhance the valve's durability and resistance to high-temperature corrosion.

[0005] DE 601 23 355 T2 describes an improved method for manufacturing poppet valves with valve seats for use in internal combustion engines, focusing on preventing problems such as burn-through during valve seat machining using plasma powder deposition welding. It highlights improvements for reducing machining steps and material waste by detailing a specific process that involves the precise application of a valve seat material and subsequent adjustments to the valve dimensions through an embossing process.

[0006] US Patent 4,075,999 A introduces a nickel-based alloy for high-temperature applications, particularly for coating engine valves. The innovation of this alloy lies in its omission of traditionally used elements such as cobalt and tungsten, thus improving cost-effectiveness and availability. The described alloy consists of nickel, chromium, and molybdenum, which enhances its high-temperature hardness, oxidation resistance, and durability. This invention claims significant improvements in wear and corrosion resistance at high temperatures. Summary of the invention: Technical problem

[0007] A wear-resistant component with a coating is manufactured by producing a substrate material, giving it a desired shape, and applying a coating to cover an area of ​​the substrate where particularly high wear resistance is desired. Although the coating can improve the durability of the wear-resistant component, it can also introduce a disadvantage. For example, a coating applied to the excavator tooth of a hydraulic excavator can increase the tooth's resistance to penetration when it enters soil and sand.

[0008] One object of the present invention is to avoid a disadvantage in a wear-resistant component with a coating, which would otherwise be caused by the formation of the coating. Solution to the problem

[0009] A wear-resistant component according to the present invention comprises a substrate material consisting of a first metal and a coating arranged in contact with the substrate material and covering an area, wherein the covered area is part of a surface of the substrate material. In a boundary section of the coating, corresponding to a boundary between the covered area and an exposed area outside the covered area on the surface of the substrate material, the exposed area and a surface of the coating are flush with each other and form a forged surface. The coating contains a matrix consisting of a second metal and hard particles dispersed in the matrix. The hard particles are located in a surface region of the coating that lies within an average particle diameter of the hard particles from the surface of the coating.Of the hard particles located in the surface area of ​​the coating, any hard particle that has an area exposed at the surface of the coating has an acute central angle corresponding to the area exposed at the surface of the coating.

[0010] As described above, a coating is applied to the surface of a substrate material by means of weld overlay or another method. In a wear-resistant component with a coating applied to it, a step is typically formed in an edge section of the coating, corresponding to the boundary between an area (covered area) covered by the coating and an area (exposed area) outside the covered area on the surface of the substrate material. This step proves to be a disadvantage due to the coating's design. For example, a coating might be applied to an excavator tooth of a hydraulic excavator.Although the formed coating can improve the wear resistance of the tooth, the resulting step may increase its resistance to penetration into soil and sand. If a coating is applied to a component intended for contact with another component, the step may prevent the component from achieving sufficient contact with the other component.

[0011] In the wear-resistant component according to the present invention, the exposed area of ​​the substrate and the surface of the coating are flush with each other in the edge section of the coating. This avoids the disadvantage caused by the coating design that would otherwise be due to the paragraph described above. If the edge section of the coating is enclosed in the forged surface, the machining step, such as cutting, by which the exposed area of ​​the substrate and the surface of the coating are made flush with each other can be omitted. This avoids the need to machine the edge section of the coating where the hardness difference is significant, and also eliminates the need to machine the coating itself, which has a high hardness.Thus, with the wear-resistant component of the present invention, it is possible to create a wear-resistant component that has a coating which avoids a disadvantage that would otherwise be caused by forming the coating.

[0012] In the wear-resistant component according to the present invention, the coating comprises a matrix consisting of a second metal and hard particles dispersed in the matrix. This facilitates the formation of a coating with excellent wear resistance.

[0013] In the wear-resistant component described above, the hard particles located in the surface region of the coating can be embedded within the coating and arranged side by side. The surface region of the coating is defined as the area within the average diameter of the hard particles measured from the surface of the coating. This prevents the hard particles from protruding significantly from the surface of the coating and thus prevents them from falling out during use of the wear-resistant component. It should be noted that the average diameter of the hard particles can be determined by examining a cross-section perpendicular to the surface of the coating with a light microscope and calculating the mean diameter of ten hard particles examined.

[0014] In the wear-resistant component described above, the hard particles located in the surface area of ​​the coating can be arranged in contact with the surface of the coating. This reduces the area of ​​each hard particle exposed at the surface of the coating, thus preventing the hard particle from detaching.

[0015] In the wear-resistant component according to the present invention, any hard particle located in the surface region of the coating that has an area exposed at the surface of the coating has an acute central angle (of less than 27°) corresponding to the area exposed at the surface of the coating. This reduces the area of ​​a hard particle exposed at the surface of the coating, thus preventing the hard particle from falling out.

[0016] In the wear-resistant component described above, the coating can have a projection in an area that forms an interface between the coating and the substrate material. This projection extends towards the substrate material, preventing the coating from detaching from the substrate.

[0017] In the machine component described above, at least part of the hard particle can be embedded in the projection. This more reliably prevents the coating from detaching from the substrate.

[0018] A method for manufacturing a wear-resistant component according to the present invention comprises the following steps: manufacturing a support element consisting of a first metal;Forming a coating that comes into contact with and covers an area, wherein the covered area is part of a surface of the support element, wherein the coating contains a matrix consisting of a second metal and hard particles dispersed in the matrix, wherein the hard particles are located in a surface region of the coating which lies within an average particle diameter of the hard particles from the surface of the coating, and wherein of the hard particles located in the surface region of the coating, any hard particle having an area exposed at the surface has an acute central angle corresponding to the area exposed at the surface of the coating;and forging of the carrier element on which the coating is formed, such that an edge section of the coating corresponding to a boundary between the covered area and an exposed area outside the covered area on the surface of the carrier material is machined to ensure that the exposed area and a surface of the coating are flush with each other and form a forged surface.

[0019] In the method for manufacturing a wear-resistant component according to the present invention, the substrate element on which the coating is formed is forged, so that the edge section of the coating is machined. This produces a wear-resistant component that has an edge section of the coating in which the surface of the coating and the exposed area of ​​the substrate material are flush with each other, forming a forged surface, thus avoiding a disadvantage that would otherwise be caused by forming the coating due to the paragraph described above. Since the edge section of the coating is enclosed in the forged surface, the machining step, such as cutting, by which the exposed area of ​​the substrate material and the surface of the coating are made flush with each other can be omitted.This eliminates the need to machine the edge section of the coating where the hardness difference is significant, as well as the need to machine the coating itself, which exhibits high hardness. Thus, with the wear-resistant component according to the present invention, it is possible to produce a wear-resistant component that has a coating which avoids a disadvantage that would otherwise be caused by the formation of the coating.

[0020] In the above-described process for manufacturing a wear-resistant component, the step of forging the substrate on which the coating is formed can include hot forging of the substrate on which the coating is formed. Using hot forging can facilitate the forging of the substrate on which the coating is formed.

[0021] In the method for producing a wear-resistant component according to the present invention, the step of forming the coating includes shaping the coating to contain a matrix consisting of a second metal as well as hard particles dispersed in the matrix. This facilitates the formation of a coating with excellent wear resistance. Effects of the invention

[0022] As can be seen from the description above, with the wear-resistant component and the method for manufacturing it according to the present invention it is possible to avoid a disadvantage in a wear-resistant component with a coating, which would otherwise be caused by the formation of the coating. Brief description of the drawings Fig. Figure 1 is a schematic representation showing the structure of a bucket of a hydraulic excavator; Fig. Figure 2 is a schematic top view showing the structure of a tooth; Fig. 3 is a schematic sectional view along line III-III in Fig. 2; Fig. Figure 4 is a schematic sectional view showing the structure of a tooth in a comparative example; Fig. Figure 5 is a schematic sectional view showing the structure of a coating on its surface and in its vicinity; Fig. Figure 6 is a schematic sectional view showing the structure at and around an interface between the coating and a substrate material; Fig. 7 is a flowchart that schematically illustrates a process for manufacturing a tooth; Fig. Figure 8 is a schematic sectional view illustrating the process for manufacturing the tooth; Fig. Figure 9 is a schematic sectional view illustrating the process for manufacturing the tooth; Fig. Figure 10 is a schematic sectional view illustrating a method for forming a coating; Fig. 11 is a photograph showing a cross-section of a tooth; Fig. 12 is an optical micrograph showing a surface of a coating and its surroundings (example); Fig. Figure 13 is an optical micrograph showing a surface of a coating and its surroundings (comparative example); Fig. 14 is an optical micrograph showing an interface between a coating and a substrate material and its surroundings (example); and Fig. Figure 15 is an optical micrograph showing an interface between a coating and a substrate material and its surroundings (comparative example); Fig. 16 is a photograph of a tooth undergoing a test for resistance to penetration (example); Fig. Figure 17 is a photograph of a tooth undergoing a test for resistance to penetration (comparative example); and Fig. Figure 18 is a diagram showing the results of the tests for resistance to penetration. Description of embodiments

[0023] One embodiment of the present invention is described below. In the following drawings, the same or corresponding parts are identified by the same reference numerals, and their description is not repeated.

[0024] A wear-resistant component according to the present embodiment is described using a hydraulic excavator tooth as an example. Fig. Figure 1 is a schematic perspective view showing the construction of a bucket of a hydraulic excavator. Fig. Figure 2 is a schematic top view showing the structure of a tooth. Fig. 3 is a schematic sectional view along line III-III in Fig. 2.

[0025] One spoonful, as it appears in Fig. The bucket shown in Figure 1, which is attached to the front end of a boom (not shown) of a hydraulic excavator, is used for excavating earth and sand. The bucket 1 contains a main body 10, which consists of a plate-like element and has an opening, a plurality (in which in Fig. Figure 16 shows a bucket 1 with three teeth 20 attached to the main body 10 such that they partially project from a circumference 12 of the opening of the main body 10 on its excavation side, and an attachment section 30 located on a side of the main body 10 opposite the side to which the teeth 20 are attached. The bucket 1 is supported by the boom of the hydraulic excavator via the attachment section 30. When the bucket 1 is used for excavation work, the teeth 20 are the first to penetrate soil and sand. The teeth 20 must therefore exhibit high wear resistance (abrasion resistance to soil and sand). The teeth 20 are abrasion-resistant components, machine components used where they come into contact with soil and sand.

[0026] A tooth 20 contains, as in Fig. Figure 2 shows a front end 21 and a rear end 22. The tooth 20 is attached to the main body 10 at the side of its rear end 22, with the side at its front end 21 projecting from the circumference 12 of the opening of the bucket 1. In operation, the tooth 20 is in contact with another component, namely the main body 10. The bucket 1 penetrates soil and sand via the side of the front end 21 of the tooth 20. Therefore, the side of the front end 21 of the tooth 20 must exhibit particularly high wear resistance (abrasion resistance to soil and sand).

[0027] Tooth 20 contains, as with reference to Fig. Figure 3 shows a substrate material 25, consisting of a first metal, and a coating 27, which is in contact with the substrate material 25 and covers a covered area 25A that is part of a surface of the substrate material 25. The first metal for the substrate material 25 can be, for example, carbon steel for use in mechanical engineering or alloy steel for use in mechanical engineering, specified according to the JIS standard (e.g., S45C or SCM435, as well as manganese steel (SMn), chromium steel (SCr), or chromium-molybdenum steel (SCM), which contains an equivalent amount of carbon).In a boundary region 29 of the coating, corresponding to a boundary between the covered region 25A and an exposed region 25B, which is a region outside the covered region 25A on the surface of the substrate material 25, the exposed region 25B and a surface 27A of the coating 27 are flush with each other and form a forged surface. The surface 27A of the coating 27 corresponds entirely to the forged surface.

[0028] Fig. Figure 4 is a schematic sectional view showing the structure of a tooth with a coating as a comparative example. When forming a coating to improve wear resistance on or near the front end of a tooth, the coating is typically formed on a steel substrate of a desired shape. Tooth 920 of the comparative example, which is a typical coated tooth, contains, as shown in Figure 4, a coating of the following structure: Fig. Figure 4 shows a front end 921 and a rear end 922. A coating 927 is formed on the side of the front end 921 of the tooth 920. The coating 927 is formed, for example, by weld overlay to cover a covered area 925A of a substrate material 925 that has been shaped as desired. Thus, at edge sections 929A, 929B, which correspond to the boundaries between the covered area 925A and exposed areas 925B, 925C outside the covered area 925A, steps are formed between the exposed areas 925B, 925C and a surface 927A of the coating 927. These steps increase the resistance of the tooth 920 when penetrating soil and sand. Furthermore, the coating 927 is formed after the substrate material 925 has been shaped. It is difficult to form the coating 927 near the front end 921.Thus, in the area encompassing the front end 921, the exposed area 925C of the front end is formed, which is not covered by the coating 927. This exposed area 925C of the front end, which has low wear resistance, accelerates wear and increases the frequency of tooth replacement 920.

[0029] In the case of tooth 20 in the present embodiment, as with reference to Fig. As can be seen in Figure 3, the exposed area 25B and the surface 27A of the coating 27 are flush with each other in the edge region 29 of the coating. This prevents an increase in penetration resistance that would otherwise be caused by a step in the edge region 29 of the coating. If the edge region 29 of the coating is enclosed in the forged surface, the machining step, for example, cutting, required to make the exposed area 25B and the surface 27A of the coating 27 flush with each other can be omitted. Therefore, machining of the edge region 29 of the coating, where the hardness difference is significant, and machining of the coating 27, which has a high hardness, can be avoided. Thus, in the tooth 20 of the present embodiment, it is possible to avoid a disadvantage that would otherwise be caused by forming the coating 27.Furthermore, a coating can be formed on a carrier element, and forging can then be carried out to form an area that encloses the front end 21. This allows the area enclosing the front end 21 to be shaped as shown in . Fig. 3 shown, easily covered with the coating 27, and a tooth 20 can be produced which has high wear resistance.

[0030] The following describes the structure of coating 27. Fig. Figure 5 is a schematic sectional view showing the structure of a coating on its surface and in its vicinity. Fig. Figure 6 is a schematic sectional view showing the structure at and around an interface between the coating and a substrate. The coating 27 contains, as referenced in Fig. 5 and Fig. Figure 6 shows a matrix 95 consisting of a second metal and hard particles 91 dispersed in the matrix 95. The second metal forming the matrix 95 can, for example, be a mixture of a metal derived from a welding wire and the first metal forming the carrier material 25. The hard particles 91 can be particles with a higher hardness than the matrix 95, such as sintered carbide particles. The coating 27 exhibits higher wear resistance (abrasion resistance to soil and sand) than the carrier material 25.

[0031] The surface 27A of the coating 27, as described in Fig. Figure 5 shows a forged surface. The hard particles 91, located in a surface region 27B of the coating, which is an area within an average particle diameter of the hard particles 91 from the surface 27A of the coating 27, are embedded in the coating 27 and arranged side by side. This prevents the hard particles 91 from protruding significantly from the surface 27A of the coating 27. This, in turn, prevents the hard particles 91 from falling out during use of the tooth 20, thereby improving the wear resistance of the tooth 20.

[0032] The hard particles 91 located in the surface area 27B of the coating can, as in Fig. Figure 6 shows that the hard particle 91 is arranged in contact with the surface 27A of the coating 27. This reduces the area of ​​a hard particle 91 exposed at the surface 27A of the coating 27, thus preventing the hard particle 91 from falling out.

[0033] A hard particle 91, which has an area exposed at the surface 27A of the coating 27, has an acute central angle θ (of less than 90°) corresponding to this exposed area. This makes the area of ​​the hard particle 91 exposed at the surface 27A of the coating 27 small, thus preventing the hard particle 91 from falling out.

[0034] In an area that includes an interface between the coating 27 and the substrate material 25, as described with reference to Fig. As can be seen in Figure 6, the coating 27 has projections 99 that extend onto the substrate 25. The projections 99 create an anchoring effect that prevents the coating 27 from detaching from the substrate 25. Each projection 99 encloses at least a portion of a hard particle 91. This more reliably prevents the coating 27 from detaching from the substrate 25. The matrix 95 of the coating 27 is located between the substrate 25 and the hard particle 91 enclosed in the projection 99. The hard particle 91 enclosed in the projection 99 is not in contact with the substrate 25. The center of the hard particle 91 is located outside the projection 99 (i.e., a portion of the hard particle 91, comprising less than half its volume, is enclosed in the projection 99). A hard particle 91 is enclosed in a projection 99.Each protrusion 99 has a depth that is smaller than the radius of the hard particle 91 contained in the protrusion 99.

[0035] A method for manufacturing a tooth 20, which is the wear-resistant component in the present embodiment, is described below with reference to Fig. 7 to 10 described. Fig. Figure 7 is a flowchart that schematically illustrates a procedure for manufacturing a tooth. Fig. 8 and Fig. Figure 9 shows schematic sectional views illustrating the process for manufacturing the tooth. Fig. Figure 10 is a schematic sectional view illustrating a method for forming a coating.

[0036] In the method for manufacturing a tooth 20 in the present embodiment, first, as with reference to Fig. As can be seen in Figure 7, a step in the production of a support element is carried out as step S10. In this step S10, as described in reference to Fig. As can be seen in Figure 8, a support element 50 is manufactured, which becomes a support material 25 of the tooth 20. The support element 50 consists of a first metal. The support element 50 is cylindrically shaped. The support element 50 has a cylindrical shape that includes one end face 52, another end face 53, and a side face 51 that connects one end face 52 and the other end face 53. A first chamfered section 52A is formed in a region where one end face 52 and the side face 51 are connected. A second chamfered section 53A is formed in a region where the other end face 53 and the side face 51 are connected. The side of one end face 52 of the support element 50 corresponds, as shown with reference to Figure 8, to the shape of the end face 52. Fig. 8 and Fig. 3 can be seen, the side of the front end 21 of the tooth 20, and the side of the other end surface 53 of the support element 50 corresponds to the side of the rear end 22 of the tooth 20.

[0037] Subsequently, a step to form a coating is executed as step S20. In this step S20, as described in reference to Fig. 8 and Fig. As can be seen in Figure 9, a coating 60 is configured to be in contact with a covered area 51A, which is part of a surface of the support element 50 formed in step S10, in order to cover the covered area 51A. The coating 60 is configured to cover a desired area of ​​the support material 25 when hot forging is performed, as described below. The covered area 51A can be determined in advance by simulating the hot forging process, for example, using a finite element method. In the present embodiment, as with reference to Figure 9, the coating 60 is configured to cover a desired area of ​​the support material 25 when hot forging is performed, as described below. The covered area 51A can be determined in advance by simulating the hot forging process, for example, using a finite element method. Fig. As can be seen in Figure 9, the coating 60 is designed to cover the side of one end surface 52 of the side surface 51, the first chamfered section 52A and one end surface 52.

[0038] The coating 60 can, for example, be formed by overlay welding using CO2 arc welding, as described below. First, a device for forming a coating is described. The device for forming a coating contains, as referenced in Fig. Figure 10 shows a welding torch 70 and a nozzle 80 for feeding hard particles. The welding torch 70 contains a welding nozzle 71, which has the shape of a hollow cylinder, and a contact tip 72, which is located inside the welding nozzle 71 and connected to a power source (not shown). A welding wire 73, which is in contact with the contact tip 72, is continuously fed to the side of the front end of the welding nozzle 71. JIS YGW12, for example, can be used for the welding wire. A gap between the welding nozzle 71 and the contact tip 72 is a flow path for shielding gas. The shielding gas flowing through the flow path is expelled from the front end of the welding nozzle 71. The nozzle 80 for feeding hard particles has the shape of a hollow cylinder. Inside the nozzle 80 for feeding hard particles, hard particles 91 are fed in and ejected via the front end of the nozzle 80 for feeding hard particles.

[0039] This device for forming a coating can be used to form a coating 60 using the method described below. With a carrier element 50 serving as one electrode and the welding wire 73 as the other electrode, voltage is applied across the carrier element 50 and the welding wire 73. This generates an arc 74 between the welding wire 73 and the carrier element 50. The arc 74 is shielded from the ambient air by the shielding gas, which is expelled from the front end of the welding nozzle 71 along the arrows β. Carbon dioxide, for example, can be used as the shielding gas. The heat in the arc 74 melts part of the carrier element 50 and also melts the front end of the welding wire 73. The melted front end of the welding wire 73 forms droplets that are transferred to the molten area of ​​the carrier element 50.This creates a melt pool 92, which is a liquid region in which the molten support element 61 and the molten welding wire 73 are mixed together. The hard particles 91, ejected through the nozzle 80 for the purpose of supplying hard particles, are fed into this melt pool 92.

[0040] When the welding torch 70 and the nozzle 80, which supply hard particles forming the device for cladding, move relative to the carrier element 50 in the direction indicated by arrow α, the position at which the molten pool 92 is formed shifts accordingly. The previously formed molten pool 92 solidifies, forming a coating 60. The coating 60 contains a matrix 95, which is formed by the solidification of the molten pool 92, as well as hard particles 91 dispersed in the matrix 95. Using the method described above, the coating 60 is formed such that it covers the covered area 51A on the surface of the carrier element 50. The surface of the carrier element 50 on which no coating 60 has been formed is the exposed area 51B. A boundary between the covered area 51A and the exposed area 51B is defined, as described with reference to Fig. Figure 9 shows an edge section 59 of the coating. It should be noted that weld overlay can be performed, for example, under the following conditions: welding current of 230 A, welding voltage of 17 V, feed rate of 110 g / min, and bead overhang of 4 mm. JIS YGW11 can be used as the welding wire. WC or W2C-based particles can be used as the hard particles.

[0041] Subsequently, a hot forging step is performed as step S30. In this step S30, the carrier element 50 with the coating 60 formed in step S20 is hot forged. The carrier element 50 with the coating 60 formed on it is then, as described in section Fig. 9 and Fig. Figure 3 shows the tooth 20 being heated to a temperature suitable for hot forging and then placed in a mold for forging. The mold has a cavity corresponding to the desired shape of the tooth 20. This hot forging process processes an area of ​​the carrier element 50 that encloses an edge section 59 of the coating. The hot forging process transforms the edge section 59 of the coating into an edge section 29 of the coating. The hot-forged edge section 59 of the coating produces a tooth 20 that has the exposed area 25B and a surface 27A of the coating 27, which are flush with each other, within the edge section 29 of the coating.In the edge section 29 of the coating, the exposed area 25B and the surface 27A of the coating 27 form a flush forged surface corresponding to the area of ​​the surface of the die used in hot forging, in which the edge section 59 of the coating is machined. In the edge section 29 of the coating, the exposed area 25B and the surface 27A of the coating 27 form a flush surface corresponding to the shape of the die used for forging. The edge section 29 of the coating is enclosed in the forged surface.

[0042] When the carrier element 50 with the coating 60 formed on it is hot-forged, as described with reference to Fig. 10 and Fig. As can be seen in Figure 5, hard particles 91, which protrude from a surface of the coating 60 during its formation, are pressed into the coating 60. As a result, the hard particles 91 located in the surface area 27B of the coating on the tooth 20 are arranged such that they are in contact with the surface 27A of the coating 27 (see Figure 5). Fig. 5) Of the hard particles 91 located in the surface area 27B of the coating, any hard particle 91 that has an area exposed at the surface 27A of the coating 27 has an acute central angle θ (of less than 27°) corresponding to the exposed area. This prevents the hard particle 91 from falling out during use of the tooth 20, thereby improving the wear resistance of the tooth 20.

[0043] When the carrier element 50 with the coating 60 formed on it is hot-forged, the tooth 20, as described in reference to Fig. 10 and Fig. As can be seen in Figure 6, protrusions 99 are formed in the coating 27 due to the hard particles 91, which were located near the interface between the coating 60 and the substrate 50 at the time of coating 60 formation. At least a portion of a corresponding hard particle 91 is incorporated into each protrusion 99. The process described above simultaneously forms the surface area of ​​the coating 27, which exhibits excellent wear resistance because the hard particles 91 are in contact with the surface 27A, and the protrusions 99, which prevent the coating 27 from detaching from the substrate 25.

[0044] Subsequently, as with reference to Fig. Figure 7 shows a heat treatment step, S40. In this step, S40, the tooth 20, produced by hot forging in step S30, undergoes heat treatment. The heat treatment performed in step S40 consists, for example, of tempering. This imparts the desired hardness and toughness to the base material 25 of the tooth 20. The tooth 20 is finished in the present embodiment using the method described above.

[0045] In the method for manufacturing a wear-resistant component in the embodiment described above, a surface section of the carrier element corresponding to the area where the coating is to be formed can be removed beforehand when forming the coating on the carrier element, or a recessed section can be formed on the carrier element before the coating is applied. This reduces the degree of deformation of the coating during forging, thereby preventing, for example, wrinkling of the forged coating. Examples

[0046] A tooth 20 was manufactured using a process similar to that described in the embodiment shown above. The structure of the coating and the like were examined (Example), and a test was also performed to verify the resistance of the manufactured tooth 20 to penetration into clay (Example). For comparison, a tooth was manufactured using a similar process, but the step for forming the coating (step S20) was omitted, and a coating was formed by weld overlay after heat treatment. The resulting tooth was subjected to a similar test (Comparative Example). The dies used for hot forging had the same shape in both the Example and the Comparative Example. The details of the tests are given below.

[0047] Fig. Figure 11 is a photograph showing a cross-section of tooth 20 of the example. In the marginal section 29 of the coating, as with reference to Fig. As can be seen in Figure 11, the exposed area 25B and the surface 27A of the coating 27 are flush with each other and form a forged surface. This confirms that the tooth 20 in the second embodiment can be manufactured using the manufacturing process described above. No cracking is observed between the coating 27 and the substrate 25. No problems occur during the hot forging process carried out after the coating has formed.

[0048] Fig. Figure 12 is an optical micrograph obtained by imaging a surface of the coating of the example and its surroundings. Fig. Figure 13 is an optical micrograph obtained by imaging a surface of the coating of the comparison example and its surroundings. In the case of the coating of the comparison example, which was formed by weld overlay and subsequently not machined by forging, the following are available, as shown in Fig. Figure 13 shows that hard particles 91 are significantly separated from the surface 27A of the coating. In the coating of the example, which was formed and subsequently machined by forging, hard particles 91 located in the surface area are shown, as with reference to Fig. As can be seen in Figure 12, the hard particles 91 are embedded in the coating (matrix 95) and arranged side by side. The hard particles 91 are aligned in contact with the surface 27A of the coating. A hard particle 91 that has an area exposed at the surface 27A of the coating 27 has an acute central angle θ (of less than 27°) corresponding to the exposed area. This is presumably due to the fact that during the forging process, the hard particles 91 that protruded from the surface 27A of the coating are pressed into the matrix 95, which has relatively low hardness.

[0049] Fig. Figure 14 is an optical micrograph obtained by imaging an interface between the coating and the substrate of the example, as well as its surroundings. Fig. Figure 15 is an optical micrograph obtained by imaging an interface between the coating and the substrate of the comparison example, as well as its surroundings. In the comparison example, where the coating was formed by weld overlay and subsequently not machined by forging, as shown in Fig. As shown in Figure 15, the interface between the coating (matrix 95) and the substrate 25 is flat. In the example, which was machined by forging after the coating was formed, the area encompassing the interface between the coating (matrix 95) and the substrate 25 is flat, as shown in Figure 15. Fig. Figure 14 shows projections 99 formed with the coating (matrix 95) that project onto the substrate material 25. A portion of a corresponding hard particle 91 is incorporated into each projection 99. It is conceivable that the projections 99 were formed due to the presence of the hard particles 91 near the interface with the substrate element during the forging process of the coating. A hard particle 91 that contributed to the formation of a projection 99 has at least one portion incorporated into the projection 99.

[0050] The following describes a test for resistance to penetration performed on a tooth. Fig. Figure 16 is a photograph obtained by depicting a manifestation of the tooth of the example that had been subjected to a test for resistance to penetration. Fig. Figure 17 is a photograph obtained by depicting a manifestation of the tooth of the comparison example after it had undergone a resistance to penetration test. In the example that was processed by forging after the coating had formed, as shown in Fig. Figure 16 shows that the surface of the tooth is flat. In the comparison example, where the surface was formed by overlay welding and subsequently not machined by forging, the coating 27 is as shown in Fig. 17 shown, present on the surface of the tooth and forming a shoulder. The in Fig. 16 and Fig. Seventeen teeth were subjected to tests in which they were driven into greasy clay, simulating soil and sand, and the resistance to penetration was measured. The rate of tooth displacement during penetration was set at 1 mm / s. Each tooth was driven into the greasy clay with a flat surface until the front end of the tooth reached a depth of 50 mm.

[0051] Fig. Figure 18 is a diagram showing the results of the penetration resistance tests. Fig. 18. The solid line and the dashed line correspond to the test results of the example and the comparison example, respectively. The resistance to penetration at the time the tooth displacement reached 50 mm was, as with reference to Fig.As can be seen in Figure 18, the resistance to penetration is approximately 0.25 kN in the comparison example and approximately 0.21 kN in the example shown. The resistance to penetration was reduced by approximately 15% in the example shown compared to the comparison example. This confirms that the tooth 20 in the embodiment shown above, which is the wear-resistant component according to the present invention, prevents an increase in resistance to penetration that would otherwise be a disadvantage caused by the formation of the coating 27.

[0052] Although in the embodiment described above a backhoe tooth for a construction machine (hydraulic excavator) was described as an example of the wear-resistant component of the present invention, the wear-resistant component according to the present invention is not limited to this and can be used, for example, in a roller, bushing, link, plate, deflection pulley, drive wheel (sprocket tooth) and other components that are part of a crawler track undercarriage of a construction machine, or in a tooth of a concrete crusher. Although in the embodiment described above a solid tooth for a small hydraulic excavator was described as a backhoe tooth, the wear-resistant component according to the present invention can also be used in a tooth for a medium or large hydraulic excavator, wherein this tooth is mounted on a bucket adapter for covering during operation. Industrial applications

[0053] The wear-resistant component and the method for manufacturing it according to the present invention can be used particularly advantageously in a wear-resistant component with a coating and the method for manufacturing it. Description of reference symbols

[0054] 1: Spoon; 10: Main body; 12: Circumference of opening; 20: Tooth; 21: Front end; 22: Rear end; 25: Carrier material; 25A: Covered area; 25B: Exposed area; 27: Coating; 27A: Surface; 27B: Surface area of ​​coating; 29: Edge section of coating; 30: Attachment section; 50: Carrier element; 51: Side face; 51A: Covered area; 51B: Exposed area; 52: One end face; 52A: First beveled section; 53: Other end face; 53A: Second beveled section; 59: Edge section of coating; 60: Coating; 70: Welding torch; 71: Welding nozzle; 72: Contact tip; 73: Welding wire; 74: Arc; 80: Hard particle feeding nozzle; 91: hard particle; 92: melting bath; 95: matrix; and 99: advantage.

Claims

[1] Wear-resistant component (20) comprising: a carrier material (25) consisting of a first metal; and a coating (27) arranged in contact with the carrier material (25) and covering an area (25A), the covered area (25A) being part of a surface of the carrier material (25), wherein: in an edge portion (29) of the coating (27) corresponding to a boundary between the covered area (25A) and an exposed area (25B) outside the covered area (25A) on the surface of the carrier material (25), the exposed area (25B) and a surface (27A) of the coating (27) are flush with each other and form a forged surface; the coating (27) contains a matrix (95) consisting of a second metal and hard particles (91) dispersed in the matrix (95); the hard particles are located in a surface area (27B) of the coating (27) which is within an average particle diameter of the hard particles (91) of the surface (27A) of the coating (27); and of the hard particles (91) located in the surface region (27B) of the coating (27), any hard particle (91) having a region exposed at the surface (27A) of the coating (27) has an acute central angle (θ) corresponding to the region exposed at the surface (27A) of the coating (27). [2] Wear-resistant component (20) according to claim 1, wherein the hard particles (91) are embedded in the coating (27) and arranged side by side. [3] Wear-resistant component (20) according to claim 2, wherein the hard particles (91) located in the surface region (27B) of the coating (27) are arranged in contact with the surface (27A) of the coating (27). [4] Wear-resistant component (20) according to one of claims 1 to 3, wherein in a region including an interface between the coating (27) and the carrier material (25), the coating (27) contains a projection (99) which projects towards the carrier material (25). [5] Wear-resistant component (20) according to claim 4, wherein at least a part of the hard particle (91) is received in the projection (99). [6] Method for producing a wear-resistant component (20), comprising the following steps: Manufacturing a support element (50) made of a first metal; Forming a coating (27) that comes into contact with and covers a region (25A), wherein the covered region (25A) is a part of a surface of the support element (50), wherein the coating (27) contains a matrix (95) consisting of a second metal and hard particles (91) dispersed in the matrix (95), wherein the hard particles (91) are located in a surface region (27B) of the coating (27) that is within an average particle diameter of the hard particles (91) of the surface (27A) of the coating (27), and wherein, of the hard particles (91) located in the surface region (27B) of the coating (27), any hard particle (91) that has a region exposed at the surface (27A) of the coating (27) has an acute central angle (θ) that corresponds to the region exposed at the surface (27A) of the coating (27) exposed; and Forging the support member (50) on which the coating (27) is formed, such that an edge portion (29) of the coating (27) corresponding to a boundary between the covered area (25A) and an exposed area (25B) outside the covered area (25A) on the surface of the support member (50) is machined to ensure that the exposed area (25B) and a surface (27A) of the coating (27) are flush with each other and form a forged surface. [7] A method of manufacturing a wear-resistant component (20) according to claim 6, wherein the step of forging the support member (50) on which the coating (27) is formed includes hot forging the support member (50) on which the coating (27) is formed.

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