Grinding wear parts having inserts surrounded by a buffer layer

Abstract

The method comprises: providing a casting mould (11) for the wear part (1); providing inserts (3); applying a buffer layer (23) to the inserts (3); positioning the inserts (3) in the casting mould (11); and casting a casting material (2) into the casting mould (11). The present invention also relates to a wear part (1), a mill for bulk material, and the use of a buffer layer (23) between ceramic inserts (3) and a metal casting material (2) in the manufacture of a wear part (1) in order to reduce cracks and / or fractures in the wear part (1).

Description

[0001] PCT154403 - Buffer layer 1

[0002] Grinding wear parts with inserts surrounded by a buffer layer

[0003] The present invention relates to a wear part for a mill, a mill, a method for manufacturing a wear part for a mill and the use of a buffer layer between ceramic inserts and a metal casting material in the manufacture of a wear part to reduce cracks and / or fractures in the wear part.

[0004] Wear parts of a mill, such as a grinding roller or a grinding plate (also called a grinding disc), are often subjected to heavy abrasive stress and can therefore wear out quickly. The maintenance and replacement of these wear parts can represent a significant economic factor. Firstly, the mill cannot be operated during this time, and secondly, the replacement itself can be very expensive.

[0005] Various methods for improving wear resistance are known in the prior art. For example, CN103111347A teaches the use of ceramic pins embedded in a steel base. DE112009003706T5 describes the use of wear plates made of hard metal or ceramic welded to a metal base. EP0476496B1 teaches the arrangement of rib-shaped wear inserts made of chrome cast iron in a metal matrix.

[0006] Due to the high and cyclical forces during the grinding process, the bond between the wear inserts and the matrix material is subjected to considerable stress. A poor bond between the wear inserts and the metal matrix negatively impacts the durability of the wear parts. When casting wear inserts into a casting material, such as a metal matrix, temperature-induced cracks can occur in the often brittle wear inserts. Furthermore, the differing thermal expansion rates of the inserts and the casting material can lead to high stress and cracking in the inserts. Additionally, cracking frequently occurs at the interface between the wear insert and the casting material during the wear part's use. These cracks negatively affect the wear resistance of the wear part.

[0007] One object of the present invention is to improve the wear resistance and durability of grinding wear parts. A further object of the present invention is to provide a simple and reliable method for manufacturing the grinding wear parts.

[0008] According to a first aspect of the invention, a method for manufacturing a wear part, in particular for manufacturing a grinding roller, a grinding plate or a grinding segment of a mill, comprises providing a mold for the wear part, arranging a separating agent in the mold, wherein the separating agent divides the mold into a first casting area and a second casting area, and arranging PCT154403 - buffer layer 2

[0009] Inserting the casting material into the mold involves pouring a first casting material into the first casting area and pouring a second casting material into the second casting area. The mold can be made of sand, for example.

[0010] The process is, in particular, a process for manufacturing a grinding wear part. The process is especially suitable for manufacturing grinding rollers, grinding roller shells, and grinding roller segments. The process is also particularly suitable for manufacturing grinding plates and grinding plate segments.

[0011] The aforementioned steps can be performed in the order mentioned or, where technically feasible, in any order. For example, the inserts can first be placed in the release agent and then placed in the mold together with the release agent. Alternatively, the release agent can first be placed in the mold, and then the inserts can be placed in the mold, for example, in or outside the release agent. Alternatively, the inserts can first be placed in the mold, and then the release agent can be placed in the mold. The use of the terms "first" and "second" casting material does not imply a sequence unless explicitly stated. For example, the second casting material can be poured before the first casting material, after the first casting material, or simultaneously with the first casting material.

[0012] The first and second casting materials can be poured into the mold at different times. In particular, the first casting material can be poured before the second.

[0013] The first casting material can have a temperature of 1000°C to 2000°C, preferably 1200°C to 1600°C, and preferably 1300°C to 1500°C, during casting. The second casting material can also have a temperature of 1000°C to 2000°C, preferably 1200°C to 1600°C, and preferably 1300°C to 1500°C, during casting. At these temperatures, a good balance between workability and thermal shock or cracking in the inserts is achieved. The first casting material can be cast at the same temperature or at a temperature that differs by at least 10°C, at least 20°C, or at least 50°C from the second casting material. This allows suitable casting conditions to be achieved, particularly with regard to preheating or the use of different first and second casting materials.

[0014] The heat input during the pouring of the first casting material into the first casting area can heat the second casting area, which is particularly adjacent to the first. In this respect, it is advantageous if the release agent is thermally conductive. The release agent can have a thermal conductivity greater than 1 watt per meter and Kelvin (W / (m*K)), preferably greater than 10 watts per meter Kelvin. PCT154403 - Buffer layer 3

[0015] The time between casting the first casting material and casting the second casting material is, in particular, less than 10 hours, more specifically less than one hour, preferably less than 30 minutes, and more preferably less than 10 minutes. The time between casting the first casting material and casting the second casting material is specifically defined as the time between the end of casting the first casting material and the beginning of casting the second casting material.

[0016] The first casting material can be located inside the wear part. The second casting material can be located in an outer area of ​​the wear part. The outer area of ​​the wear part is, in particular, that part of the wear part which, during the intended use of the wear part, comes into contact with the material being ground in the mill. The outer area of ​​the wear part can, in particular, contribute to the grinding of the material. The outer area of ​​the wear part can come into contact with the material being ground during the grinding process. The second casting material is, for example, located on a grinding surface of a grinding roller or a grinding surface of a grinding disc.

[0017] The first casting material can be identical to the second casting material. The first casting material can be the same as the second casting material. The first casting material can be different from the second casting material. The first casting material can be a metal casting material. The second casting material can be a metal casting material.

[0018] The first casting material can be a ductile casting material. This first casting material can be more ductile than the second. A ductile material ensures a good bond between the inserts and the casting material. In particular, a ductile material is less prone to cracking, so the inserts remain firmly anchored in the casting material even under continuous cyclic loading. The first casting material could be, for example, cast iron or cast steel. However, ductile material can be relatively less wear-resistant.

[0019] The second casting material can be a wear-resistant material. The second casting material can be a white-hardening cast iron. Since the second casting material is located in an outer area of ​​the wear part, particularly a grinding surface, it can be advantageous for the second casting material to be wear-resistant. This can improve the resistance and durability of the wear part. The second casting material can, in particular, be more wear-resistant than the first casting material. By combining ductile and wear-resistant casting materials, advantageous anchoring of the inserts and a wear-resistant surface can be achieved. The second casting material can include, and in particular consist of, nickel chilled cast iron.

[0020] The second casting material, especially if it is designed as a wear-resistant material, can be brittle. The second casting material can be prone to cracking. PCT154403 - Buffer layer 4

[0021] Cracks can form, in particular, on a grinding surface of the second casting material and / or at the interface between the second casting material and the inserts. The inserts can create a notch effect in the second casting material. This notch effect can lead to cracks in the second casting material. In particular, cyclic or repetitive stress, such as during a grinding process, can cause microcracks to form in the second casting material at the location of the inserts. With continued cyclic or repetitive stress, these microcracks can propagate into macrocracks. The cracks can grow towards the interior of the wear part. The release agent can stop or limit crack growth. The release agent can prevent cracks from propagating from the second casting material into the first casting material.

[0022] The first separating agent can be a separating plate, a separating wall, or a separating fabric. The separating agent, in particular the separating plate, can have a thickness of 0.5 millimeters to 20 millimeters, preferably 1 millimeter to 10 millimeters, preferably 2 millimeters to 5 millimeters.

[0023] The separating agent may comprise or consist of a metal. For example, the separating agent may comprise or consist of an iron-based material, steel, or a nickel-based material. In particular, the separating agent has a melting point at least 10, at least 20, at least 50, or at least 100 degrees Celsius higher than the temperature at which the first and / or second casting material is poured. This ensures that the separating agent is not excessively damaged by the pouring process, especially the pouring of the first casting material, and that it holds the inserts in position. In particular, the separating agent has a melting point at most 150, at most 100, at most 50, or at most 20 degrees Celsius higher than the temperature at which the first and / or second casting material is poured.This allows the release agent to melt slightly, at least locally on the surface, which can lead to a better bond between the casting material and the release agent.

[0024] The separating agent can consist of or be composed of several separating agent segments. In the case of a grinding roller, the separating agent, in particular the separating plate, can extend circumferentially, especially completely (360 degrees), around an axis of rotation of the grinding roller. The separating agent can consist of several separating agent segments such that the separating agent segments collectively extend completely circumferentially around the axis of rotation. The separating agent segments can be attached to one another in the mold, for example, by welding. The separating agent can have a constant distance or radius from the axis of rotation of the grinding roller. In the case of a grinding plate, the PCT154403 - buffer layer 5

[0025] The separating agent may be arranged in a middle layer of the grinding plate. The separating agent may be arranged horizontally in the grinding plate, particularly with regard to the intended use of the grinding plate.

[0026] The release agent can be designed to prevent or restrict the flow of the first casting material from the first casting area into the second casting area. The release agent can also be designed to prevent or restrict the flow of the second casting material from the second casting area into the first casting area.

[0027] The inserts can be arranged in or on the release agent. This allows the position of the inserts to be fixed in the mold before the first and second casting materials are poured. For example, the inserts can first be arranged outside the mold in or on the release agent, and then the release agent, together with the inserts arranged in or on it, can be placed in the mold.

[0028] The inserts can be arranged on or within the release agent. The inserts can be attached to the release agent, in particular by bonding with a temperature-resistant adhesive. The inserts can be arranged on a surface of the release agent, in particular a surface facing the second casting area. The release agent can then be arranged in only one of the two casting areas, in particular the second casting area. The release agent can have recesses. The inserts can be arranged in the recesses. The inserts can extend through the recesses. The inserts can then extend into both the first and second casting areas. The position of the recesses in the release agent determines the subsequent position of the inserts. The number of recesses in the release agent corresponds, in particular, to the number of inserts.

[0029] Alternatively or additionally, the inserts can be attached or positioned in the mold by means of a carrier, for example, a wire mesh or support sheet. The carrier can, for example, be located in the second casting area. The inserts can be located only in the second casting area. The inserts can be attached or positioned in or on the carrier and additionally extend through recesses in the release agent. The inserts can be attached or positioned in or on the carrier and additionally attached to the release agent, for example, a surface of the release agent facing the second casting area. The carrier can be permeable to the casting material, in particular the second casting material. Alternatively or additionally, the inserts can be attached directly to the mold using a temperature-resistant adhesive.Alternatively or additionally, the inserts can be positioned in the mold, for example, pressed into a sand layer of the mold. PCT154403 - Buffer layer 6.

[0030] The inserts can have an inner base and an outer base, and in particular extend from the inner base to the outer base along a longitudinal axis. Each insert can have a recess and / or a notch extending circumferentially. The recess or notch can be located closer to the inner base than to the outer base.

[0031] The longitudinal axis of the inserts can be arranged radially along the grinding roller in the case of a grinding roller. In the case of a grinding plate, the longitudinal axis of the inserts can be arranged vertically within the grinding plate, particularly with regard to the intended use of the grinding plate. The inner base surface is located, in particular, inside the wear part. The outer base surface is located, in particular, in the outer region or on the grinding surface of the wear part.

[0032] The recesses in the release agent can be circular. The inserts can have a circular cross-section.

[0033] The inserts can essentially have a circular cross-section. The inserts can have a circular cross-section at least on their inner base. The inserts can have a circular cross-section at least on their outer base. The inserts can have a cylindrical inner region. The inner region includes, in particular, the inner base. The inner region can extend from the inner base to the recess or notch of the inserts. The diameter of the inner base or the cylindrical inner region can be equal to or smaller than the diameter of the recesses in the release agent. This allows the inserts, in particular the inner base or the inner region of the inserts, to be inserted into the recesses.The inserts, particularly their outer bases, can have a cross-section with a larger diameter than the recesses in the separating material. This cross-section can be located longitudinally between the outer base and the recess or notch of the inserts, or it can correspond to the outer base. This prevents the inserts from moving completely through the recesses in the separating material. The inserts can have an outer region, which in particular includes the outer base. This outer region can extend from the outer base to the recess or notch of the inserts. The outer base of the inserts can have a larger diameter than the inner base of the inserts.

[0034] The inner base can have a polygonal cross-section, for example, a triangle, a square, a regular pentagon, a regular hexagon, a regular octagon, or the like. The inserts can be used instead of the PCT154403 buffer layer 7.

[0035] The cylindrical inner area may have a prismatic inner area, which in particular comprises the polygonal inner base. The shape of the recesses in the separating agent can be identical to the shape of the inner base or the cross-section of the inner area of ​​the inserts.

[0036] The recess can be the same size as or larger than the inner base area. The difference between the diameter of the recess and the inner base area or the prismatic / cylindrical inner region is 0 to 20 millimeters, preferably 1 to 15 millimeters, preferably 2 to 10 millimeters. This prevents the casting material from flowing through the recesses next to the inserts. The diameter is specifically defined as the greatest distance between two opposite side faces through the center point. The diameter is specifically defined as the diameter of the circumference of the inserts, particularly the inner base area or the prismatic / cylindrical inner region.

[0037] The outer base can have a polygonal cross-section, for example, a triangle, a square, a regular pentagon, a regular hexagon, a regular octagon, or the like. The outer area of ​​the inserts can be prismatic and, in particular, encompass the polygonal outer base. The shape of the recesses can differ from the shape of the outer base or the cross-section of the outer area of ​​the inserts.

[0038] The inner base can have the same shape as the outer base. For example, both bases can be circular or polygonal. The inner and outer bases can have the same shape with the same diameter or different diameters. The shape of the inner base can differ from the shape of the outer base. The inner and outer bases can have different shapes with the same diameter or different diameters. For example, the inner base can be circular and the outer base polygonal, or vice versa.

[0039] The inserts can be mushroom-shaped. The inserts can be designed in such a way that the head of the mushroom shape does not fit through the recesses in the release agent. The inserts can be designed in such a way that the base of the mushroom shape does not fit through the recesses in the release agent.

[0040] The inserts can be embedded in the first casting material and the second casting material. The inner area of ​​the inserts, in particular the inner base, can be located closer to the first casting material than the outer base. The inner area of ​​the inserts, in particular the inner base, can be located in the first casting material. The outer area of ​​the inserts, in particular the outer base, can be located in the second casting material. The first casting material can be more ductile than the second. PCT154403 - Buffer layer 8

[0041] The casting material can be the first, and the second casting material can be more wear-resistant than the first. This allows for a particularly wear-resistant surface for wear parts. Furthermore, even if cracks form in the second casting material, the inserts can be anchored in the more ductile first casting material.

[0042] Alternatively, the inserts can be embedded solely in the second casting material. Specifically, the inner and outer areas can be located within the second casting material. In this case, the inserts can be arranged or attached to a surface of the release agent, particularly a surface facing the second casting material or casting area. Alternatively or additionally, the inserts can be arranged or attached to or within the support. The support is located, in particular, within the second casting area or casting material. In this case, the first casting material at least preheats the second casting area and / or the inserts, thereby preventing or reducing cracking and brittle fracture in the inserts.

[0043] In this case, the process may involve attaching the inserts to or within the carrier in the second casting area. The inserts may be embedded in the second casting material. Specifically, the inserts may not be embedded in the first casting material.

[0044] The inserts may include ceramics, in particular consist of ceramics. The inserts may include silicon ceramics, in particular consist of silicon ceramics.

[0045] The inserts can include silicon nitride, and in particular consist of silicon nitride. The inserts can include silicon carbide, and in particular consist of silicon carbide. Ceramics have particularly wear-resistant properties. By using ceramics, especially silicon ceramics such as silicon nitride or silicon carbide, the wear resistance of the wear part can be improved.

[0046] Alternatively, the inserts can include, or consist of, hard metals, for example tungsten carbide hard metals.

[0047] Ceramic and / or carbide inserts, in particular, are prone to cracking under rapid temperature stress. This phenomenon is also known as thermal shock. The risk of cracking can be reduced by casting the first and second materials at different times. Casting the first material preheats the second casting area and / or the inserts, thus reducing or mitigating the thermal shock.

[0048] The second casting material can have a thickness or height of 5 millimeters to 200 millimeters, in particular 15 millimeters to 50 millimeters, preferably 15 millimeters to 25 millimeters. The inserts can have a height, in particular their longest extent along a main axis, of 10 millimeters to 150 millimeters, in particular 15 millimeters to 100 millimeters, in particular 15 millimeters to 50 millimeters. PCT154403 - Buffer layer 9

[0049] preferably 20 millimeters to 30 millimeters, particularly in thickness or height direction of the second casting material.

[0050] The thickness or height of the second casting material can be 30% to 300%, in particular 50% to 90%, preferably 60% to 80% of the height of the inserts.

[0051] Providing the mold may involve manufacturing a hybrid mold. The hybrid mold may have a first component made of water glass-bonded sand. The hybrid mold may have a second component made of furan resin-bonded sand. The hybrid mold particularly allows for preheating of the mold.

[0052] The second component can be located in an outer area of ​​the mold. The first component can be located in an inner area of ​​the mold. During the casting process, the first component can come into contact with the casting material, particularly with the second casting material. The first component can determine the shape of the wear part.

[0053] The process may include preheating the mold, particularly before pouring the second casting material. The process may also include preheating the inserts, particularly before pouring the second casting material.

[0054] The process can include preheating the first casting area. The process can include preheating the second casting area. Preheating the first casting area can be achieved by external heat supply, for example, by radiant heaters or warm air. Preheating the second casting area can be achieved by external heat supply, for example, by radiant heaters or warm air. Preheating the inserts can be achieved by external heat supply, for example, by radiant heaters or warm air.

[0055] Preheating the mold, particularly the second casting area, and / or the inserts can be achieved by transferring heat from the first casting material. The heat from the first casting material can be conducted to the second casting area and / or the inserts via the release agent. Iron casting materials, such as cast iron or cast steel, can retain a very high temperature, especially above 500 degrees Celsius, even several hours or minutes after the casting process, making them well-suited for preheating the second casting area. Preheating can reduce or prevent cracking in the inserts. It can also reduce or prevent the risk of thermal shock.

[0056] The process may include preheating the mold, in particular the first casting area and / or the second casting area, to a temperature of 100 degrees Celsius to 1500 degrees Celsius, in particular 300 degrees Celsius to 1200 degrees Celsius, and in particular 600 degrees Celsius to 900 degrees Celsius. The process may include PCT154403 - Buffer Layer 10

[0057] Preheating the inserts to a temperature of 100 degrees Celsius to 1500 degrees Celsius, in particular from 300 degrees Celsius to 1200 degrees Celsius, and in particular from 600 degrees Celsius to 900 degrees Celsius, shall include.

[0058] The method can include applying a buffer layer to the inserts. The inserts can be completely covered with a buffer layer. The inserts can be completely covered with a buffer layer, except for the outer base surface. The buffer layer can be configured as described in the fifth or sixth aspect of the invention.

[0059] The buffer layer can comprise, and in particular consist of, refractories, carrier fluid, binders, and / or regulating agents. The buffer layer can have a thickness of 0.3 mm to 5 mm, in particular 1 mm to 2 mm, and in particular 1.3 mm to 1.7 mm. The inserts can be coated with the buffer layer before the casting of the first material and before the casting of the second material.

[0060] The buffer layer protects the inserts, particularly from rapid heat input. The buffer layer can (at least partially) compensate for the different thermal expansion rates of the inserts and the casting material. The buffer layer can insulate the inserts against thermal shock. The buffer layer can reduce or prevent cracking in the inserts. In particular, the combination of preheating the inserts / mold and the buffer layer can further reduce cracking in the inserts. The buffer layer can be designed as described in the fifth or sixth aspect.

[0061] The separating agent can be a first separating agent, in particular an external separating agent. The method can include the arrangement of a second separating agent, in particular an internal separating agent. The first separating agent and the second separating agent can together divide the mold into a first casting area, a second casting area, and a third casting area.

[0062] The first casting area corresponds to the first casting area described above. The second casting area corresponds to the second casting area described above. The third casting area can be arranged between the first and second casting areas. The process can include casting a third casting material into the third casting area. The third casting material can be composed like the first casting material described above. The third casting material can be composed like the second casting material described above. The first, second, and third casting materials can be composed identically. The first, second, and third casting materials can consist of the same casting material. The casting of the third casting material then takes place between the casting of the first casting material and the casting of the PCT154403 buffer layer 11.

[0063] The second casting material is used. The third casting material can have a temperature of 1000 degrees Celsius to 2000 degrees Celsius during casting, preferably 1200 degrees Celsius to 1600 degrees Celsius, preferably 1300 degrees Celsius to 1500 degrees Celsius.

[0064] The first separating agent can be positioned closer to a grinding surface of the wear part than the second separating agent. In the case of a grinding roller, the first and second separating agents can be arranged concentrically. The second separating agent can be continuous. In particular, the second separating agent has no recesses.

[0065] The arrangement of the first, second and third casting area as well as the first and second separating means can be carried out as described in the second aspect of the invention, in particular in the first, second or third exemplary embodiment.

[0066] According to a second aspect of the invention, a wear part comprises a first casting material, a second casting material, a separating agent, and at least one insert. The separating agent is arranged between the first casting material and the second casting material. The at least one insert is embedded in at least the second casting material. The wear part can have several inserts. The inserts can be arranged regularly distributed over a grinding surface of the wear part. The wear part is, in particular, a grinding roller, a grinding plate, or a grinding segment. The wear part can correspond to the wear part described in the first aspect of the invention.

[0067] The first casting material can correspond to the first casting material described in the first aspect of the invention. The second casting material can correspond to the second casting material described in the first aspect of the invention. The release agent can correspond to the release agent described in the first aspect of the invention, in particular the first release agent. The at least one insert(s) can correspond to the inserts described in the first aspect of the invention.

[0068] The at least one insert can extend through at least one recess in the separating agent. The at least one insert can be arranged in at least one recess in the separating agent. The inserts can extend through recesses in the separating agent. The inserts can be arranged in recesses in the separating agent. Alternatively or additionally, the at least one insert can be arranged or attached to a support, for example, a wire mesh or support sheet. Alternatively or additionally, the inserts can be arranged or attached to a support, for example, a wire mesh or support sheet.

[0069] At least one insert(s) can be additionally surrounded by a buffer layer, which can reduce cracking. The buffer layer can be PCT154403 - Buffer Layer 12

[0070] The buffer layer can correspond to the buffer layer described in the first aspect of the invention. The buffer layer can correspond to the buffer layer described in the fifth aspect of the invention. The buffer layer can correspond to the buffer layer described in the sixth aspect of the invention.

[0071] At least one insert can be embedded in the first casting material and in the second casting material. The inserts can be embedded in the first casting material and in the second casting material.

[0072] A first exemplary embodiment comprises a first casting area and a second casting area separated by a first separating element. The inserts can be arranged in recesses in the separating element. The inserts can extend into both the first and second casting areas. Alternatively, the inserts can be arranged on a surface, in particular a surface facing the second casting area, of the separating element. The inserts can extend from the separating element into the second casting area. First, the first casting area is filled with a first casting material, thereby embedding an inner region of the inserts in the first casting material (provided the inserts extend through recesses in the separating element). The separating element prevents the first casting material from flowing into the second casting area.The high temperature of the first casting material preheats the second casting area and the inserts, primarily through thermal radiation and / or conduction. This reduces or prevents cracking and / or thermal shock in the inserts. The thermal shock to the inserts during the pouring of the first casting material is also reduced, as only the inner area of ​​the inserts is in contact with the first casting material (provided the inserts extend through recesses in the release agent). Subsequently, a second casting material is poured into the second casting area, thereby embedding at least an outer area of ​​the inserts, particularly the remaining portion.

[0073] The second casting material is a wear-resistant casting material, as described in the first aspect. The wear resistance of the wear part can be increased by the wear-resistant casting material in the second casting area, particularly at the grinding surface. Cracks that occur in the wear-resistant casting material can be stopped by the separating plate, preventing them from propagating into the first casting material. The inserts comprise silicon ceramic, in particular silicon carbide or silicon nitride. In a preferred embodiment, the inserts consist essentially of silicon nitride. The inserts can also consist of a different material, for example, without silicon ceramic. PCT154403 - Buffer layer 13

[0074] According to a first alternative of the first exemplary embodiment, the first casting material is also a wear-resistant casting material, in particular the same material as the second casting material. This simplifies the casting process.

[0075] According to a second alternative of the first exemplary embodiment, the first casting material is a ductile casting material, in particular more ductile than the second casting material, for example cast iron or cast steel. This allows the inserts to be better anchored in the first casting material and / or further reduces cracking.

[0076] A second exemplary embodiment comprises a first casting area and a second casting area separated by a first separating element, in particular a separating plate. The inserts are arranged on or attached to a support, for example, a support plate. The inserts and the support are arranged in the second casting area. First, the first casting area is filled with a first casting material. The separating element prevents the first casting material from flowing into the second casting area. In contrast to the first exemplary embodiment, the separating element has no recesses. The high temperature of the first casting material preheats the second casting area and the inserts, in particular by thermal radiation. Subsequently, a second casting material is poured into the second casting area, thereby embedding the inserts.The second casting material is a wear-resistant casting material, as described in the first aspect. The inserts comprise silicon ceramic, in particular silicon carbide or silicon nitride. In a preferred embodiment, the inserts consist essentially of silicon nitride. The inserts can also consist of a different material, for example, without silicon ceramic.

[0077] In comparison to the first exemplary embodiment, the thermal shock of the inserts is reduced because they do not come into contact with the first casting material. Only after preheating by the high temperature of the first casting material are the inserts encased in the second casting material, thereby reducing thermal shock and cracking.

[0078] According to a first alternative of the second exemplary embodiment, the first casting material is also a wear-resistant casting material, in particular the same material as the second casting material. This simplifies the casting process.

[0079] According to a second alternative of the second exemplary embodiment, the first casting material is a ductile casting material, in particular more ductile than the second casting material, for example cast iron or cast steel. This allows the inserts to be better anchored in the first casting material and / or further reduces cracking. PCT154403 - Buffer layer 14

[0080] A third exemplary embodiment comprises a first casting area, a second casting area, and a third casting area. The third casting area is arranged between the first and second casting areas. A first separating means, in particular a first separating plate, separates the second casting area from the third casting area. A second separating means, in particular a second separating plate, separates the third casting area from the first casting area. The second casting area forms an outer region of the wear part, in particular the grinding surface. The first casting area forms the interior of the wear part. The first separating means is arranged closer to the future grinding surface than the second separating means.

[0081] The inserts are arranged in recesses in the first release agent. The inserts extend into the second and third casting areas. First, the first casting area is filled with a first casting material. The second release agent prevents the first casting material from flowing into the third casting area. The high temperature of the first casting material preheats the third casting area and the inserts, primarily through thermal radiation. Subsequently, a third casting material is poured into the third casting area, embedding an inner portion of the inserts within the third casting material. The first release agent prevents the third casting material from flowing into the second casting area.

[0082] The high temperature of the third casting material preheats the second casting area and the inserts, primarily through thermal radiation and / or conduction. This reduces or prevents cracking and / or thermal shock in the inserts. The thermal shock to the inserts during the pouring of the third casting material is also reduced because, firstly, the inserts and the third mold are already preheated by the first casting material, and secondly, only the inner area of ​​the inserts is in contact with the third casting material. Subsequently, a second casting material is poured into the second casting area, embedding an outer area of ​​the inserts, specifically the remaining portion. The second casting material is a wear-resistant material, as described in the first aspect. The inserts comprise silicon ceramics, specifically silicon carbide or silicon nitride.In a preferred embodiment, the inserts consist essentially of silicon nitride. The inserts can also be made of a different material, for example, without silicon ceramic.

[0083] According to a first alternative of the third exemplary embodiment, the first casting material and the third casting material are also wear-resistant casting materials, in particular the same material as the second casting material. This simplifies the casting process. Compared to the previous two exemplary embodiments, crack propagation is limited by two release agents. PCT154403 - Buffer layer 15

[0084] According to a second alternative of the third exemplary embodiment, the first casting material is a ductile casting material, in particular more ductile than the second casting material, for example, cast iron or cast steel. The third casting material is also a ductile casting material, in particular the same material as the first casting material. The second alternative of the third exemplary embodiment best reduces the risk of cracking and thermal shock. Two release agents are provided for crack control. Both the inner and outer areas of the inserts are preheated before casting. The inner area of ​​the inserts is embedded in ductile material.

[0085] In each of the described exemplary embodiments, the inserts can additionally be surrounded by a buffer layer, which can further reduce cracking. The buffer layer can correspond to the buffer layer described in the first aspect of the invention. The buffer layer can correspond to the buffer layer described in the fifth aspect of the invention. The buffer layer can correspond to the buffer layer described in the sixth aspect of the invention.

[0086] The disclosed embodiments relate to the method according to the first aspect of the invention and the wear part according to the second aspect of the invention.

[0087] According to a third aspect of the invention, a mill for bulk materials, in particular for minerals or ores, comprises a wear part according to the second aspect of the invention.

[0088] A fourth aspect of the invention provides for the use of composite casting for embedding wear-resistant inserts in the manufacture of a wear part, particularly for mitigating temperature-induced cracks. The inserts can be designed as described in the first or second aspect of the invention. The composite casting can comprise the casting of a first casting material and a second casting material. The composite casting, in particular the first casting material and the second casting material, can be designed as described in the first or second aspect of the invention.

[0089] According to a fifth aspect of the invention, a method for manufacturing a wear part, in particular for manufacturing a grinding roller, a grinding plate, or a grinding segment of a mill, comprises providing a mold for the wear part, providing inserts, optionally applying a buffer layer to the inserts, arranging the inserts in the mold, and pouring a casting material into the mold. The mold can, for example, be made of sand.

[0090] The process is, in particular, a process for manufacturing a grinding wear part. The process is especially suitable for manufacturing grinding rolls, grinding roll shells, and PCT154403 - buffer layer 16.

[0091] Suitable for grinding roller segments. The process is particularly suitable for the production of grinding plates and grinding plate segments.

[0092] The aforementioned steps can be carried out in the order mentioned or, if technically feasible, in any order. For example, the preparation of the mold can also take place after or simultaneously with the application of the buffer layer to the inserts.

[0093] The buffer layer can reduce or prevent cracking, especially in the inserts. The buffer layer can reduce or prevent fractures, especially in the inserts. The buffer layer acts primarily as an expansion buffer between the casting material and the inserts. The buffer layer also provides insulation and can counteract thermal shock to the inserts.

[0094] The casting material can correspond to the first casting material described in the first aspect of the invention. The casting material can correspond to the second casting material described in the first aspect of the invention. The casting material can correspond to the third casting material described in the first aspect of the invention. The casting material can comprise the first casting material and the second casting material. The mold can correspond to the mold described in the first aspect of the invention. The mold can have a first casting area, a second casting area, and / or a third casting area. The casting areas can be separated from one another by one or more separating means, as described in the first aspect of the invention.

[0095] The inserts can be arranged in a separating agent, in particular in recesses in the separating agent, as described in the first aspect of the invention. The inserts can, for example, be attached to or within a separating agent, as described in the first aspect of the invention. The position of the recesses in or on the separating agent determines the subsequent position of the inserts.

[0096] Alternatively or additionally, the inserts can be attached or positioned in the mold using a support, such as a wire mesh or support sheet. Alternatively or additionally, the inserts can be attached directly to the mold using a temperature-resistant adhesive. Alternatively or additionally, the inserts can be positioned within the mold, for example, by pressing them into a layer of sand within the mold.

[0097] The buffer layer can have a thickness of 0.3 mm to 10 mm, preferably 1 mm to 5 mm, preferably 1 mm to 2 mm, preferably 1.3 mm to 1.7 mm, before the casting material is poured into the mold. Such a thickness sufficiently reduces cracking or breakage of the inserts during the casting process. PCT154403 - Buffer layer 17

[0098] The thickness of the buffer layer can be proportional to the size of the inserts. The thickness of the buffer layer can be proportional to the inner and / or outer diameter of the inserts. The inner diameter of the inserts is, in particular, the shortest distance between two opposite lateral edges of the outer base of the inserts through the center of the outer base. The inner diameter of the inserts is, in particular, defined as the diameter of the incircle of the outer base of the inserts. The outer diameter of the inserts is, in particular, the longest distance between two opposite lateral edges of the outer base of the inserts through the center of the outer base. The outer diameter of the inserts is, in particular, defined as the diameter of the circumcircle of the outer base of the inserts.

[0099] The buffer layer can have a thickness of 0.5 percent to 20 percent, preferably 2 percent to 10 percent, preferably 2 percent to 5 percent, preferably 2.5 percent to 3.5 percent, of the inner diameter of the inserts before the casting material is poured into the mold.

[0100] The buffer layer can have a thickness of 0.5 percent to 20 percent, preferably 2 percent to 10 percent, preferably 2 percent to 5 percent, preferably 2.5 percent to 3.5 percent, of the outer diameter of the inserts before the casting material is poured into the mold.

[0101] After the casting process, the buffer layer may be thinner than before the casting process.

[0102] The buffer layer can comprise refractories, carrier fluid, binders, and / or regulating agents. The buffer layer specifically comprises refractories, carrier fluid, binders, and regulating agents. The buffer layer can consist of refractories, carrier fluid, binders, and / or regulating agents.

[0103] Examples of refractory materials include coke, graphite, quartz, zirconium silicate, mica, talc, magnesite, aluminum silicate, chamotte, as well as metallurgically active and other components. Combinations of these materials are also possible. Examples of carrier fluids are water or alcohol. Examples of binders include synthetic resins, soluble and swellable silicates, ethylene vinyl acetate, polyester, epoxy resin, polyurethane, or natural materials such as starch.

[0104] The buffer layer can be thixotropic. This means that the buffer layer can be easily applied as a liquid and then remains stationary in a liquid state.

[0105] The buffer layer can be applied to the inserts by brushing. The buffer layer can be applied to the inserts by spraying. The buffer layer can be applied to the inserts by rollers. The buffer layer can be applied to the inserts by dipping. The inserts are immersed in a bath containing the buffer layer material. The buffer layer can be applied electrostatically. PCT154403 - Buffer layer 18

[0106] The buffer layer is applied to the inserts. Preferably, it can be applied by pouring it onto the inserts. Optionally, the inserts are guided through a curtain / waterfall of liquid. For this purpose, the inserts can be placed on a grating and / or a conveyor belt. Combinations of the described methods for applying the buffer layer are also possible.

[0107] The casting material can have a temperature of 1000 degrees Celsius to 2000 degrees Celsius, preferably 1200 degrees Celsius to 1600 degrees Celsius, preferably 1300 degrees Celsius to 1500 degrees Celsius, when poured into the mold.

[0108] The casting material can have a coefficient of thermal expansion of 7 to 15 micrometers per Kelvin, in particular 8.5 to 13.5 micrometers per Kelvin, and in particular 9 to 13 micrometers per Kelvin. The inserts, and in particular the insert material, can have a coefficient of thermal expansion of 1 to 7 micrometers per Kelvin, in particular 2 to 6 micrometers per Kelvin, and in particular 3 to 5 micrometers per Kelvin.

[0109] The buffer layer compensates for the different temperature-induced deformations in the casting material and the inserts. It also reduces internal stresses in the inserts and / or the casting material, and reduces residual stresses in the wear part.

[0110] The buffer layer, and in particular the material of the buffer layer, can have a lower modulus of elasticity than the inserts. The buffer layer, and in particular the material of the buffer layer, can have a lower modulus of elasticity than the casting material. The buffer layer can have a modulus of elasticity of 5 to 100 megapascals, and in particular of 10 to 50 megapascals. The lower modulus of elasticity allows the different temperature-induced deformations between the inserts and the casting material to be at least partially compensated. The buffer layer acts in particular as a thermal expansion buffer. The modulus of elasticity can in particular be a compression or modulus of elasticity. The moduli of elasticity refer in particular to the solidified or cured state at room temperature.

[0111] The casting material can comprise metal casting material. The casting material can comprise high-alloy, wear-resistant cast iron. The casting material can correspond to the second casting material described in the first aspect of the invention. The casting material can correspond to the first casting material described in the first aspect of the invention.

[0112] The inserts may include ceramic. The inserts may be made of ceramic. The inserts may include silicon ceramic, in particular silicon nitride or PCT154403 - buffer layer 19

[0113] Silicon carbide, and in particular consisting thereof. The inserts can correspond to the inserts described in the first aspect of the invention. The shape of the inserts can correspond to the shape of the inserts described in the first aspect of the invention.

[0114] Providing the mold may involve manufacturing a hybrid mold. The hybrid mold may have a first component made of water glass-bonded sand. The hybrid mold may have a second component made of furan resin-bonded sand. The hybrid mold particularly allows for preheating of the mold.

[0115] The second component can be located in an outer area of ​​the mold. The first component can be located in an inner area of ​​the mold. During the casting process, the first component can come into contact with the casting material, particularly with the second casting material. The first component can determine the shape of the wear part.

[0116] The method can include preheating the mold, particularly before pouring the casting material. The method can include preheating the inserts, particularly before pouring the casting material. The method can include preheating both the mold and the inserts, particularly before pouring the casting material. The preheating can be carried out as described in the first aspect of the invention. Preheating can reduce or prevent the risk of thermal shock.

[0117] The process may include preheating the mold to a temperature of 100°C to 1500°C, in particular 300°C to 1200°C, and in particular 600°C to 900°C. The process may also include preheating the inserts to a temperature of 100°C to 1500°C, in particular 300°C to 1200°C, and in particular 600°C to 900°C.

[0118] According to a sixth aspect of the invention, a wear part comprises a casting material and a plurality of inserts embedded in the casting material. The inserts are, in particular, each individually embedded in the casting material, i.e., surrounded by the casting material. The inserts are, in particular, not directly surrounded by the casting material. According to the invention, the inserts are each, at least partially, surrounded by a buffer layer.

[0119] The wear part is, in particular, a grinding roller, grinding plate, or grinding segment. The wear part can correspond to the wear part described in the fifth aspect of the invention. PCT154403 - Buffer layer 20

[0120] The buffer layer can correspond to the buffer layer described in the fifth aspect of the invention. The casting material can correspond to the casting material described in the fifth aspect of the invention. The inserts can correspond to the inserts described in the first aspect of the invention and / or the fifth aspect of the invention.

[0121] The casting material can surround the inserts, at least in certain areas, without direct contact. A buffer layer is specifically arranged between the casting material and the inserts. The casting material can also be in direct contact with the inserts, at least in certain areas. For example, the thickness of the buffer layer can be reduced to zero during the casting process, so that the casting material comes into contact with the inserts, at least in certain areas.

[0122] The inserts can be completely surrounded by the buffer layer. The inserts can be completely surrounded by the buffer layer, except for the outer base. The inserts can be surrounded by the buffer layer on their lateral surfaces.

[0123] The buffer layer can have a thickness of 0 to 10 millimeters, in particular 1 to 5 millimeters, and especially 1.3 to 1.7 millimeters. In particular, the buffer layer can have a thickness of 1 to 1.5 millimeters. Such a thickness can sufficiently reduce cracking or breakage of the inserts during the casting of the material. Additionally, the buffer layer can at least partially compensate for the differing degrees of expansion of the inserts and the material during use of the wear part, for example, during a grinding process. The buffer layer can reduce cracking in the wear part, in particular in the inserts and / or the material, during use. The thickness of the buffer layer is, in particular, the thickness of the buffer layer.

[0124] The buffer layer can have a thickness of 0.5 percent to 20 percent, preferably 2 percent to 10 percent, preferably 2 percent to 5 percent, preferably 2.5 percent to 3.5 percent, of the inner diameter of the inserts. The inner diameter of the inserts is, in particular, the shortest distance between two opposite lateral edges of the outer base of the inserts through the center of the outer base. The inner diameter of the inserts is, in particular, defined as the diameter of the incircle of the outer base of the inserts.

[0125] The buffer layer can have a thickness of 0.5 percent to 20 percent, preferably 2 percent to 10 percent, preferably 2 percent to 5 percent, preferably 2.5 percent to 3.5 percent, of the outer diameter of the inserts. The outer diameter of the inserts is, in particular, the longest distance between two opposite side edges of the outer base of the inserts through the center point of the outer buffer layer.

[0126] Base area. The outer diameter of the inserts is specifically defined as the diameter of the circumcircle of the outer base area of ​​the inserts.

[0127] The casting material can include metal casting material, in particular high-alloy, wear-resistant cast iron. The inserts can include ceramics, in particular silicon ceramics, for example, silicon nitride or silicon carbide. The inserts can consist of ceramics, in particular silicon ceramics. The use of wear-resistant cast iron in combination with ceramic inserts can improve the wear resistance of the wear part. However, due to the different coefficients of thermal expansion of these materials, stresses and cracking can occur. The use of the buffer layer can reduce these stresses and / or cracking.

[0128] According to a seventh aspect of the invention, a mill for bulk materials, in particular for minerals or ores, comprises a wear part according to the sixth aspect of the invention.

[0129] An eighth aspect of the invention comprises the use of a buffer layer between ceramic inserts and a metal casting material during the manufacture of a wear part to reduce cracks and / or fractures in the wear part, particularly in the metal casting material and / or in the ceramic inserts. Alternatively or additionally, the eighth aspect of the invention comprises the use of a buffer layer between ceramic inserts and a metal casting material during the manufacture of a wear part to compensate for differing thermal expansions of the ceramic inserts and the metal casting material, particularly during the casting of the metal casting material.

[0130] The inserts can be configured as described in the first, second, fifth, or sixth aspect of the invention. The inserts can be configured as described in the fifth or sixth aspect of the invention. The metal casting material can be configured as the first or second casting material described in the first or second aspect of the invention. The metal casting material can comprise the first and / or second casting material described in the first or second aspect of the invention. The metal casting material can be configured as the casting material described in the fifth or sixth aspect of the invention.

[0131] The following statements refer to the first aspect, the second aspect, the third aspect, the fourth aspect, the fifth aspect, the sixth aspect, the seventh aspect, and the eighth aspect of the invention.

[0132] The wear part can be a grinding roller or a grinding plate. The grinding roller can have a radius of 90 mm to 1500 mm, preferably 250 mm to 1250 mm. The radius of the grinding roller is defined in particular as the radial distance from the axis of rotation of the grinding roller to the working surface of the grinding roller. The grinding plate PCT154403 - buffer layer 22

[0133] The grinding plate can have a radius of 200 mm to 3600 mm, preferably 500 mm to 3350 mm. The radius of the grinding plate is defined in particular as the radial distance from the center of the grinding plate to an outer edge of the grinding plate.

[0134] The inserts are primarily wear inserts. The inserts can be densely packed. The inserts can be solid. The inserts can be made entirely of ceramic. The inserts can have a density of 2 grams per cubic centimeter (g / cm³). 3) up to 4 grams per cubic centimeter, preferably 2.5 grams per cubic centimeter up to 3.5 grams per cubic centimeter, preferably 3.1 grams per cubic centimeter up to 3.3 grams per cubic centimeter.

[0135] The inserts can be essentially pore-free. The inserts can have a pore content of less than 5% by volume, preferably less than 3% by volume, preferably less than 1% by volume. The inserts can have a pore content of less than 0.1% by volume.

[0136] The inserts can consist essentially of silicon ceramic. The ceramic inserts can comprise a silicon-carbon compound, in particular silicon carbide. The inserts can consist of a silicon-carbon compound, in particular silicon carbide. The inserts can comprise a silicon-nitrogen compound, in particular silicon nitride. The inserts can consist of a silicon-nitrogen compound, in particular silicon nitride.

[0137] The inserts can contain at least 70% silicon by mass, preferably 80% silicon by mass, preferably 90% silicon by mass, particularly in the form of silicon carbide or silicon nitride. The inserts can contain at least 70% silicon by mass, preferably 80%, preferably 90% silicon by mass, or silicon carbide or silicon nitride.

[0138] Ceramics possess particularly good wear-resistant properties. The use of ceramics, especially silicon ceramics such as silicon nitride or silicon carbide, can improve the wear resistance of the wear part. Alternatively, the inserts can include, or consist of, hard metals, for example, tungsten carbide cemented carbides.

[0139] The inserts can have the shape disclosed in EP application No. 24168081.8 entitled “Silicon ceramic inserts in grinding wear parts”, filed on 2 April 2024, in particular the shapes disclosed therein in Figures 2 to 12 and 18, and the accompanying description. Instead of the polygonal upper / outer area, the inserts can also have a cylindrical / circular upper / outer area.

[0140] The casting material, the first casting material, the second casting material, and / or the third casting material may include or consist of wear-resistant material, such as metal casting material or white-hardening cast iron. The casting material, PCT154403 - Buffer Layer 23

[0141] The first, second, and / or third casting material may comprise or consist of high-alloy, wear-resistant cast iron. The casting material may comprise or consist of nickel chilled cast iron. The nickel chilled cast iron may be Ni-Hard, in particular Ni-Hard IV. The nickel chilled cast iron may contain 8% to 10% chromium by mass. The nickel chilled cast iron may contain 4% to 6.5% nickel by mass. The nickel chilled cast iron may contain 1.5% to 2.5% silicon by mass. The nickel chilled cast iron may essentially contain 9% chromium by mass, 5% nickel by mass, and 2% silicon by mass.

[0142] The wear resistance of the wear part can be improved by using a wear-resistant material, particularly in an outer area or on the grinding surface. Wear resistance can be further enhanced by using wear-resistant inserts, for example, made of ceramic. Wear-resistant materials can be brittle and prone to cracking or fracture, especially during rapid temperature changes. Cracking or fracture in the casting material and / or inserts can be reduced or prevented by using a buffer layer and / or preheating the mold or inserts.

[0143] Part of the casting material, the first casting material and / or the third casting material, may include or consist of a ductile casting material. A ductile material ensures a good bond between the inserts and the casting material. In particular, a ductile material is less susceptible to cracking, so the inserts remain firmly anchored in the casting material even under continuous cyclic loading. Part of the casting material, the first casting material and / or the third casting material, may, for example, include or consist of cast iron or cast steel.

[0144] The buffer layer can consist of several individual layers. For example, it can consist of one, two, three, four, five, six, seven, eight, nine, or ten individual layers. The buffer layer can be applied in multiple individual layers. For example, 0.1 to 0.5 millimeters, and in particular 0.2 to 0.3 millimeters, of the buffer layer can be applied with each pouring, brushing, spraying, rolling, coating, or dipping process. The previously applied individual layer can be allowed to dry between each process.

[0145] The buffer layer can have a modulus of elasticity of 5 to 100 megapascals, in particular 7 to 50 megapascals, and in particular 10 to 15 megapascals. The casting material can have a modulus of elasticity of 150 to 250 gigapascals, in particular 170 to 220 gigapascals, and in particular 180 to 210 gigapascals. The inserts, in particular the ceramic inserts, PCT154403 - buffer layer 24

[0146] They can exhibit an elastic modulus of 300 to 500 gigapascals, in particular 350 to 450 gigapascals, and especially 380 to 430 gigapascals. The previously defined values ​​for the elastic modulus can, in particular, be values ​​for the compression modulus or the modulus of elasticity under compression.

[0147] The elastic modulus of the casting material can be at least 100 times, in particular at least 1000 times, and in particular at least 10000 times, the elastic modulus of the buffer layer. The elastic modulus of the inserts (in particular the ceramic inserts) can be at least 200 times, in particular at least 2500 times, and in particular at least 25000 times, the elastic modulus of the buffer layer. The elastic moduli refer in particular to the solidified or cured state at room temperature.

[0148] The buffer layer can be applied to all surfaces of the inserts, in particular the outer surfaces, the outer base, and the inner base. The buffer layer can be applied to the outer surfaces of the inserts. The inner base of the inserts may not have a buffer layer. This improves the bond between the inserts and the metal casting.

[0149] The buffer layer can contribute to, or be designed to, compensate for differing thermal expansion rates between the metal casting and the inserts. The buffer layer can contribute to, or be designed to, reduce residual stresses in the inserts and / or the metal casting, particularly those caused by differing thermal expansion rates of the metal casting and the inserts. The buffer layer can contribute to, or be designed to, compensate for differing expansion and / or deformation between the metal casting and the inserts.

[0150] The method according to the first aspect of the invention can be used to manufacture a wear part according to the second and / or sixth aspect of the invention. The method may also include process steps from the method according to the fifth aspect of the invention.

[0151] The wear part according to the second aspect of the invention can be manufactured using process steps of the method according to the first and / or fifth aspect of the invention. The components described in the wear part, in particular the inserts, the casting material, the buffer layer and / or the release agents, can be designed as described in the first, fifth or sixth aspect of the invention.

[0152] The mill according to the third aspect of the invention can comprise one or more wear parts according to the second and / or sixth aspect of the invention. PCT154403 - Buffer layer 25

[0153] The use according to the fourth aspect of the invention may include the method or method steps according to the first and / or fifth aspect of the invention. The use according to the fourth aspect of the invention may be carried out with a wear part according to the second and / or sixth aspect of the invention.

[0154] The method according to the fifth aspect of the invention can be used to manufacture a wear part according to the second and / or sixth aspect of the invention. The method may also include process steps from the method according to the first aspect of the invention.

[0155] The wear part according to the sixth aspect of the invention can be manufactured using process steps of the method according to the first and / or fifth aspect of the invention. The components described in the wear part, in particular the inserts, the casting material, the buffer layer and / or the release agents, can be designed as described in the first, second or fifth aspect of the invention.

[0156] The mill according to the seventh aspect of the invention may comprise one or more wear parts according to the second and / or sixth aspect of the invention.

[0157] The use according to the eighth aspect of the invention may include the method or method steps according to the first and / or fifth aspect of the invention. The use according to the eighth aspect of the invention may be carried out with a wear part according to the second and / or sixth aspect of the invention.

[0158] As used in the description of the various described embodiments and the attached claims, the singular forms are to be understood as also including the plural forms and vice versa, unless the context clearly indicates otherwise.

[0159] The terms "first," "second," "third," and "fourth" are simply to be understood as designations for a specific element or component and do not necessarily indicate a particular order or arrangement of the components or elements mentioned. For example, the presence of a fourth element / component does not necessarily imply the presence of a first, second, or third element / component, and vice versa.

[0160] For the purposes of this description and the accompanying claims, unless otherwise specified, all numbers expressing amounts, quantities, percentages, etc., are to be understood as being modified in all cases by the term "approximately". Furthermore, all ranges include the specified maximum and minimum values ​​as well as all intermediate ranges, which may or may not be expressly enumerated herein. In this context, a number A is therefore to be understood as A ± 5% of A. In this context, a number A can be understood to include numerical values ​​that are within the general standard error for measuring the property PCT154403 - Buffer Layer 26.

[0161] The number A may, in some cases as used in the appended claims, deviate by the percentages listed above, provided that the amount by which A deviates does not substantially impair the fundamental and novel feature(s) of the claimed invention.

[0162] Advantageous embodiments of the invention are explained in more detail below with reference to the accompanying figures.

[0163] Figure 1 shows a perspective view of a wear part according to the invention in the form of a grinding roller.

[0164] Figure 2 shows a perspective view and a side view of an insert according to the invention as shown in Fig. 1.

[0165] Figure 3 shows a perspective view of a casting mold according to the invention for a wear part according to the invention in the form of a grinding roller.

[0166] Figure 4 shows a perspective sectional view of the mold according to the invention as shown in Fig. 3.

[0167] Figure 5 shows a top view of a section of a first exemplary embodiment of a casting mold according to the invention, as well as a sectional view of a section of a first exemplary embodiment of a wear part according to the invention.

[0168] Figure 6 shows a top view of a section of a second exemplary embodiment of a casting mold according to the invention, as well as a sectional view of a section of a second exemplary embodiment of a wear part according to the invention.

[0169] Figure 7 shows a top view of a section of a third exemplary embodiment of a casting mold according to the invention, as well as a sectional view of a section of a third exemplary embodiment of a wear part according to the invention.

[0170] Figure 8 shows a top view of a section of a grinding surface of a wear part according to the invention.

[0171] Figure 9 shows a top view of a section of a grinding surface of a wear part according to the invention in an alternative embodiment to Fig. 8.

[0172] Fig. 1 shows a perspective view of a wear part 1 according to the invention in the form of a grinding roller. The grinding roller 1 has a cast material 2 and a plurality of inserts 3. The inserts 3 are surrounded by or embedded in the cast material 2. The grinding roller 1 has a working surface 4. The working surface 4 is also referred to as the grinding surface 4. In the intended use of the grinding roller 1, the working surface 4 faces the material to be ground. The working surface 4 is arranged in the radially outer region of the grinding roller 1. The inserts 3, or the outer buffer layer 27, are formed by the PCT154403.

[0173] The bases 5 of the inserts 3 are arranged within the work surface 4. The outer bases 5 of the inserts 3 form the work surface 4. The inserts 3 are shown with a regular octagonal cross-section for illustrative purposes only. Other cross-sectional shapes, such as a circle, are also possible.

[0174] Fig. 2 shows a perspective view and a side view of an insert 3 according to the invention as shown in Fig. 1. By way of example, this insert has an octagonal shape in its outer region. Alternatively, the insert 3 has an outer base 5 and an inner base 6. The outer base 5 is arranged opposite the inner base 6. The insert 3 extends along a longitudinal direction 100 between the inner base 6 and the outer base 5. The outer base 5 has, by way of example, a regular octagonal cross-section. The inner base 6 has, by way of example, a circular cross-section. The insert 3 has an outer region 7 and an inner region 8. The outer region 7 comprises the outer base 5. The inner region 8 comprises the inner base 6. Optionally, a notch 9 is arranged between the inner region 7 and the outer region 8.The notch 9 extends circumferentially around the insert 3. In some embodiments, the notch 8 may be interrupted. The outer region 7, or outer base 5, optionally has a larger diameter than the inner region 8, or inner base 6. This ensures that the insert 3 does not fit completely through a recess in a separating plate. The outer region 7 has eight lateral surfaces 10. The insert 3 shown in Fig. 2 has an exemplary mushroom shape. As an alternative to the octagonal cross-section shown in Fig. 2, the outer region 7, or outer base 5, can have a circular cross-section, as shown in Figs. 3, 4, and 9.

[0175] Fig. 3 shows a perspective view of a mold 11 for a wear part 1 according to the invention in the form of a grinding roller. The mold 11 has a core 12 and an outer area 13. Between the core 12 and the outer area 13, the mold 11 defines a casting area 14. By way of example, the casting area 14 is shown as a ring in Fig. 3, since the mold 11 shown in Fig. 3 is designed for the production of a grinding roller 1. The mold 11 shown in Fig. 3 is intended for the production of an entire grinding roller 1. It is also possible for the mold 11 to be designed for the production of a segment of the grinding roller 1, for example, 30 degrees of the grinding roller. This is particularly advantageous for grinding rollers 1 with a large diameter. Other shapes of the mold 11 are also possible and result in particular from the wear part to be produced.

[0176] In the mold 11, particularly in the casting area 14, a separating agent 15 in the form of a separating plate is arranged. The separating plate 15 is annular and extends circumferentially around the core 12. The separating plate 15 can consist of several PCT154403 - buffer layer 28

[0177] The separating plate segments are composed of a plurality of recesses 16. The separating plate 15 has a plurality of recesses 16. The recesses 16 are, for example, arranged regularly in the separating plate 15, as shown in Fig. 3. A plurality of inserts 3 are arranged in the recesses. One insert 3 is arranged in each recess 16.

[0178] The separating plate 15 divides the casting area 14 into a first casting area 17 and a second casting area 18. The first casting area 17 is located inside the mold 11 and forms an inner area of ​​the wear part 1. The second casting area 18 is located in an outer area of ​​the mold 11 and forms an outer area of ​​the wear part 1, in particular the working / grinding surface 4 of the wear part. The inserts 3 extend through the recesses 16 in the separating plate 15. The inner area 8 of the inserts 3 is located in the first casting area 17. The outer area 7 of the inserts 3 is located in the second casting area 18.

[0179] Fig. 3 shows the mold 11 including separating plate 15 and inserts 3 before casting the casting material, in particular before casting the first casting material and the second casting material.

[0180] Fig. 4 shows a perspective sectional view of the mold 11 shown in Fig. 3. The mold 11, or rather the outer area 13 of the mold 11, is shown as an example of a hybrid mold. The hybrid mold 11 has a first component 19 and a second component 20. The first component 19 can consist of water glass-bonded sand. The second component 20 can consist of furan resin-bonded sand. The first component 19 defines the working surface 4 of the wear part 1 to be produced.

[0181] Fig. 5 shows a top view of a section of a first exemplary embodiment of a casting mold 11 according to the invention. Only the casting area 14, or a section thereof, is shown. Fig. 5 also shows a sectional view of a section of a first exemplary embodiment of a wear part 1 according to the invention, using a grinding roller as an example. The section plane is orthogonal to the axis of rotation of the grinding roller 1.

[0182] The casting area 14 comprises a first casting area 17 and a second casting area 18, which are separated by a separating agent 15 in the form of a separating plate. The inserts 3 are arranged in recesses 16 in the separating plate. The inserts 3 extend into the first casting area 17 and the second casting area 18. Alternatively, the inserts 3 can be arranged or attached to a side of the separating agent 15 facing the second casting area 18 and, in particular, may not extend through the separating agent 15. During casting, the first casting area 17 is first filled with a first casting material 21, thereby embedding the inner area 8 of the inserts 3 in the first casting material 21. The separating plate 15 prevents the first casting material 21 from flowing into the second casting area 18. Due to the high temperature of the first PCT154403 - buffer layer 29

[0183] The second casting area 18 and the inserts 3 are preheated with the casting material 21, in particular by thermal radiation and / or thermal conduction. Subsequently, a second casting material 22 is poured into the second casting area 18, thereby embedding the outer area 7 of the inserts 3. The outer base surfaces 5 of the inserts 3 form part of the grinding surface 4 of the manufactured wear part 1.

[0184] The second casting material 22 is a wear-resistant casting material, as described, for example, in the first aspect of the invention. According to a first alternative of the first embodiment, the first casting material 21 is also a wear-resistant casting material, in particular the same material as the second casting material 22. According to a second alternative of the first embodiment, the first casting material 21 is a ductile casting material, in particular more ductile than the second casting material 22, for example cast iron or cast steel, as described, for example, in the first aspect of the invention.

[0185] Optionally, the inserts 3 are at least partially surrounded by a buffer layer 23. The buffer layer 23 is applied before casting the first casting material 21 and the second casting material 22. The buffer layer 23 can also be present after the casting process, i.e., in the finished wear part 1. The buffer layer 23 can, for example, be configured as described in the fifth or sixth aspect of the invention.

[0186] Fig. 6 shows a top view of a section of a second exemplary embodiment of a casting mold 11 according to the invention. Only the casting area 14, or a section thereof, is shown. Fig. 6 also shows a sectional view of a section of a second exemplary embodiment of a wear part 1 according to the invention, using a grinding roller as an example. The section plane is orthogonal to the axis of rotation of the grinding roller 1.

[0187] The casting area 14 comprises a first casting area 17 and a second casting area 18, which are separated by a separating element 15 in the form of a separating plate. The inserts 3 are arranged on or attached to a support 24 in the form of a support plate. The inserts 3 and the support plate 24 are arranged in the second casting area 18. During casting, the first casting area 17 is first filled with a first casting material 21. The separating plate 15 prevents the first casting material 21 from flowing into the second casting area 18. In contrast to the first exemplary embodiment, the separating plate 15 has no recesses. The high temperature of the first casting material 21 preheats the second casting area 18 and the inserts 3, particularly by thermal radiation. Subsequently, a second casting material 22 is poured into the second casting area 18, thereby embedding the inserts 3. The outer PCT154403 buffer layer 30

[0188] The base surfaces 5 of the inserts 3 represent a part of the grinding surface 4 of the manufactured wear part 1.

[0189] The second casting material 22 is a wear-resistant casting material, as described, for example, in the first aspect of the invention. According to a first alternative of the second embodiment, the first casting material 21 is also a wear-resistant casting material, in particular the same material as the second casting material 22. According to a second alternative of the second embodiment, the first casting material 21 is a ductile casting material, in particular more ductile than the second casting material 22, for example cast iron or cast steel, as described, for example, in the first aspect of the invention.

[0190] Optionally, the inserts 3 are at least partially surrounded by a buffer layer 23. The buffer layer 23 is applied before casting the first casting material 21 and the second casting material 22. The buffer layer 23 can also be present after the casting process, i.e., in the finished wear part 1. The buffer layer 23 can, for example, be configured as described in the fifth or sixth aspect of the invention.

[0191] Fig. 7 shows a top view of a section of a third exemplary embodiment of a casting mold 11 according to the invention. Only the casting area 14, or a section thereof, is shown. Fig. 7 also shows a sectional view of a section of a third exemplary embodiment of a wear part 1 according to the invention, using a grinding roller as an example. The section plane is orthogonal to the axis of rotation of the grinding roller 1.

[0192] The casting area 14 comprises a first casting area 17, a second casting area 18, and a third casting area 25. The third casting area 25 is arranged between the first casting area 17 and the second casting area 18. A first separating element 15, in the form of a first separating plate, separates the second casting area 18 from the third casting area 25. A second separating element 26, in the form of a second separating plate, separates the third casting area 25 from the first casting area 17. The second casting area 18 forms an outer region of the wear part 1, in particular the grinding surface 4. The first casting area 17 forms the interior of the wear part 1. The first separating element 15 is arranged closer to the future grinding surface 4 than the second separating element 26.

[0193] The inserts 3 are arranged in recesses 16 in the first separating plate 15. The inserts 3 extend into the second casting area 18 and the third casting area 25. First, the first casting area 17 is filled with a first casting material 21. The second separating plate 25 prevents the first casting material 21 from flowing into the third casting area 25. The second separating plate 25, in particular, has no recesses. Due to the high temperature of the first casting material 21, the third casting area 25 and the inserts PCT154403 - buffer layer 31

[0194] 3. Preheated, in particular by thermal radiation. Subsequently, a third casting material 27 is poured into the third casting area 25, thereby embedding the inner area 8 of the inserts in the third casting material 27. The first separating plate 15 prevents the third casting material 27 from flowing into the second casting area 18.

[0195] The high temperature of the third casting material 27 preheats the second casting area 18 and the inserts 3, primarily through thermal radiation and / or conduction. Subsequently, a second casting material 22 is poured into the second casting area 18, thereby embedding the outer area 7 of the inserts 3. The outer base surfaces 5 of the inserts 3 form part of the grinding surface 4 of the manufactured wear part 1.

[0196] The second casting material 22 is a wear-resistant casting material, as described, for example, in the first aspect of the invention. According to a first alternative of the third exemplary embodiment, the first casting material 21 and the third casting material 27 are also wear-resistant casting materials, in particular the same material as the second casting material 22. According to a second alternative of the third exemplary embodiment, the first casting material 21 is a ductile casting material, in particular more ductile than the second casting material 22, for example cast iron or cast steel, as described, for example, in the first aspect of the invention. The third casting material 27 is also a ductile casting material, in particular the same material as the first casting material 21.

[0197] Optionally, the inserts 3 are at least partially surrounded by a buffer layer 23. The buffer layer 23 is applied before casting the first casting material 21, the second casting material 22, and the third casting material 27. The buffer layer 23 can also be present after the casting process, i.e., in the finished wear part 1. The buffer layer 23 can, for example, be configured as described in the fifth or sixth aspect of the invention.

[0198] Fig. 8 shows a top view of a section of a grinding surface 4 of a wear part 1 according to the invention. The inserts 3 are embedded in the second casting material 22, that is, at least partially surrounded by the second casting material 22. The second casting material 22 and the outer base surfaces 5 of the inserts 3 form the grinding surface 4 of the wear part. The inserts 3, in particular the outer surfaces 10 of the inserts 3, are surrounded, at least partially, by a buffer layer 23. The buffer layer 23 is arranged between the inserts 3 and the second casting material 22. By way of example, the inserts 3, or rather the outer base surfaces 5 of the inserts 3, have an octagonal shape in Fig. 8. However, this is only to be understood as an example. Other shapes, such as inserts 3 with a circular cross-section, as shown in Figs. 3 and 4, are also possible. PCT154403 - Buffer layer 32

[0199] Fig. 9 shows a further top view of a section of a grinding surface 4 of a wear part 1 according to the invention in an alternative embodiment to Fig. 8. In comparison to Fig. 8, the outer base surfaces 5 of the inserts 3 have a circular cross-section in the embodiment shown in Fig. 9.

Claims

PCT154403 - Buffer layer 33 Claims 1. Method for manufacturing a wear part (1), in particular a grinding roller or a grinding plate of a mill, comprising: - Providing a mold (11) for the wear part (1), - Provision of deployments (3), - Applying a buffer layer (23) to the inserts (3), - Arranging the inserts (3) in the mold (11), and - Pouring a casting material (2) into the mold (11), wherein the buffer layer (23) has a lower modulus of elasticity than the inserts (3) and the casting material (2).

2. Method according to claim 1, wherein the buffer layer (23) has a thickness of 0.3 millimeters to 10 millimeters, in particular 1 millimeter to 5 millimeters, in particular 1.3 millimeters to 1.7 millimeters, before the casting material (2) is poured into the mold (11).

3. Method according to claim 1 or 2, wherein the buffer layer (23) comprises refractories, carrier liquid, binders and / or regulating agents.

4. Method according to one of the preceding claims, wherein the buffer layer (23) is applied to the inserts (3) by pouring, brushing, spraying, rolling, electrostatic coating and / or dipping.

5. Method according to one of the preceding claims, wherein the casting material (2) has a temperature of 1000 degrees Celsius to 2000 degrees Celsius, preferably 1200 degrees Celsius to 1600 degrees Celsius, preferably 1300 degrees Celsius to 1500 degrees Celsius, when poured into the mold.

6. A method according to any one of the preceding claims, wherein the casting material (2) has a coefficient of thermal expansion of 7 micrometers per Kelvin to 15 micrometers per Kelvin, in particular of 8.5 micrometers per Kelvin to 13.5 micrometers per Kelvin, in particular of 9 micrometers per Kelvin to 13 micrometers per Kelvin, and the inserts have a coefficient of thermal expansion of 1 micrometer per Kelvin to 7 micrometers per Kelvin, in particular of 2 micrometers per Kelvin to 6 micrometers per Kelvin, in particular of 3 micrometers per Kelvin to 5 micrometers per Kelvin. PCT154403 - Buffer layer 34 7. Method according to one of the preceding claims, wherein the casting material (2) comprises metal casting material, in particular high-alloy, wear-resistant cast iron.

8. Method according to any of the preceding claims, wherein the inserts (3) comprise ceramics, in particular consist of ceramics.

9. Method according to one of the preceding claims, wherein providing the mold (11) comprises producing a hybrid mold, wherein the hybrid mold in particular comprises a first component (19) of water glass-bound sand and a second component (20) of furan resin-bound sand.

10. Method according to any of the preceding claims, wherein the method comprises preheating the mold (11) and / or the inserts (3), in particular before casting the casting material (2).

11. Wear part (1), in particular a grinding roller or a grinding plate of a mill, comprising a casting material (2), and a plurality of inserts (3) embedded in the casting material (2), wherein the inserts (3) are each at least partially surrounded by a buffer layer (23), wherein the buffer layer (23) has a lower modulus of elasticity than the inserts (3) and the casting material (2).

12. Wear part according to claim 11, wherein the buffer layer (3) has a thickness of 0.1 millimeters to 10 millimeters, in particular of 1 millimeter to 5 millimeters, in particular of 1.3 millimeters to 1.7 millimeters.

13. Wear part according to claim 11 or 12, wherein the casting material (2) comprises metal casting material, in particular high-alloy, wear-resistant cast iron, and the inserts (3) comprise ceramic, in particular silicon ceramic.

14. Mill for bulk material, in particular minerals or ores, comprising a wear part (1) according to one of claims 11 to 13. PCT154403 - Buffer layer 35 15. Use of a buffer layer (23) between ceramic inserts (3) and a metal casting material (2) in the manufacture of a wear part (1) to compensate for different thermal expansion of the ceramic inserts (3) and the metal casting material (2) and / or to reduce cracks and / or fractures in the wear part (1), in particular in the metal casting material (2) and / or in the ceramic inserts (3).

16. Method according to any one of claims 1 to 10, wear part according to any one of claims 11 to 13, mill according to claim 14 or use according to claim 15, wherein the casting material (2) comprises white-hardening cast iron or nickel chilled cast iron, and wherein the inserts (3) comprise ceramic, in particular silicon ceramic.

17. Method according to any one of claims 1 to 10, wear part according to any one of claims 11 to 13, mill according to claim 14 or use according to claim 15, wherein the buffer layer (23) is thixotropic.

18. Method according to any one of claims 1 to 10, wear part according to any one of claims 11 to 13, mill according to claim 14 or use according to claim 15, wherein the buffer layer has a modulus of elasticity of 5 megapascals to 100 megapascals, in particular 7 megapascals to 50 megapascals, in particular 10 megapascals to 15 megapascals.

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