Replaceable bucket tooth

Abstract

The present invention relates to a replaceable bucket tooth with enhanced durability and performance characteristics. This innovative tooth design addresses the challenge of meeting high material demands while extending operational lifespan. Previous manufacturing methods of bucket teeth, such as weld overlay, mechanical attachment of diverse materials, and differential heat treatments including induction hardening, flame hardening, and selective salt bath quenching cannot be used to create a multi metallic bucket tooth. The manufacturing described herein allows for unprecedented design freedom, enabling the strategic placement of different materials at varying thicknesses throughout the tooth structure resulting in a replaceable bucket tooth which optimizes the tooth's performance in specific areas subject to different mechanical stresses, corrosive environments, or physical demands. The invention also encompasses a bucket tooth arrangement incorporating this replaceable tooth, suitable for use in excavator or mining buckets.

Description

[0001] REPLACEABLE BUCKET TOOTH

[0002] The present disclosure relates to a replaceable bucket tooth, a bucket tooth arrangement and the use of a replaceable bucket tooth or a bucket tooth arrangement in an excavator or mining bucket.

[0003] Background

[0004] A bucket tooth is a crucial component of excavating and mining equipment, including loaders, excavators, and dragline buckets. These teeth are attached to the leading edge of the bucket and perform several essential functions. Primarily, bucket teeth enhance the bucket's ability to penetrate tough materials such as rock, compacted soil, and debris. Constructed from high-strength materials like hardened steel or multi alloy compound materials, bucket teeth are engineered to endure heavy wear and tear in harsh mining environments. By protecting the bucket from damage and wear, these teeth significantly extend the operational life of the equipment.

[0005] In addition to their protective function, bucket teeth also improve the efficiency and productivity of excavation and mining operations. Their design allows for smoother and more effective digging, reducing the strain on the machinery and the amount of energy required for operation. This results in lower fuel consumption and operational costs.

[0006] Bucket teeth are typically made from a variety of high-strength materials, including hardened steel, alloy steel, carbon steel, , and high manganese steel. These materials are selected for their durability and resistance to wear and tear in harsh operating conditions. The teeth are most commonly manufactured through casting or forging processes, sometimes followed by an overlay process like chromium carbide overlay (CCO) or tungsten carbide overlay (TCO), ensuring a robust and reliable construction.

[0007] One of the key advantages of bucket teeth is their replaceability. This modularity allows for easy replacement when the teeth wear out or break, minimizing downtime and reducing maintenance costs. The ability to quickly swap out worn teeth means that equipment can return to operation swiftly, enhancing overall productivity. Furthermore, the process of replacing bucket teeth is designed to be straightforward, often requiring only basic tools and minimal time. This ease of maintenance is crucial in mining and excavation operations where equipment uptime is paramount. Regular inspection and timely replacement of bucket teeth can prevent more extensive damage to the bucket and the machine, further extending the operational life of the equipment.

[0008] The manufacturing of components requiring different mechanical, corrosive or physical properties in different areas is often complicated. There are several ways that different properties can be achieved including weld overlay, mechanically attaching different materials together, differential heat treatment by induction hardening, flame hardening, or selective salt bath quenching. All these methods have different drawbacks, and it can be very difficult, if possible, to achieve drastically different materials properties within a component, using these methods.

[0009] In some operations the operating life of the cast bucket teeth used today is a mere 8-24 hours of operation, depending on ground conditions and time of year. The most common material used is cast carbon steel at 50-55 HRC hardness or Hadfield (Mn-steel) type steel. While the tooth could be forged and machined in a better material this would not be economically feasible as any life increase would only be marginal. Instead, operators are using PTAW overlays in strategic areas of the cast tooth to increase life. The material used are often a Ni-alloy matrix with a substantial amount of W-carbide. This does work to some extent, but it suffers from a several issues e.g.:

[0010] • The overlays are relatively thin 5-15mm and the usable wear thickness of the tooth is an order of magnitude larger than that.

[0011] • The solution suffers from an eggshell effect. This causes cracking and spalling of the coating when it's too thin when the cast steel underneath the coating deforms from the massive loads. This can happen even if there is a substantial coating thickness left.

[0012] • As soon as a small section of the coating has spalled off a weak spot is formed. The wear eats away much faster at the exposed steel and an edge effect on the overlay follows where the exposed edges wear fast due to the brittle nature of the overlay without steel backing support.

[0013] The hardness and wear resistance of the materials used for bucket teeth today are limited by the toughness. Cast materials are inherently relative brittle and are today at the limit to what is usable.

[0014] The increase in life that is achieved with the overlayed teeth is limited as that overlay suffers from afore mentioned issues. On top of that, the overlay only constitutes a very small portion of the total wear volume of the tooth.

[0015] One strategy to meet the requirements both for mechanical strength and toughness is to apply a highly wear-resistant material on a strong and tough steel base as a reinforcement where needed. Advanced composites and extreme alloys can be challenging to join with other materials due to their complex structure and properties. One proposed solution to this has been presented in Journal of Manufacturing and Materials Processing, 2023,7,51, where friction welding is used to attach a 15V tool steel to a cast shovel tooth base. The use of friction welding means that there is no heat treatment performed after friction welding, the material will be less robust and of a lower quality than what is preferred in the mining industry. Furthermore, the geometries achievable with friction welding are limited.

[0016] It hence exists a need for a replaceable bucket tooth that have a longer operating life while still meeting the high demands on the materials of the tooth.

[0017] It is therefore an aspect of the present disclosure to provide a replaceable bucket tooth that shows a longer operating life while still meeting the very high demands on the materials. In addition to meeting the high material demands, the manufacturing process should have a design freedom that different materials in the tooth can be placed anywhere and at any thickness. A further object is to present disclosure on a bucket tooth arrangement comprising the replaceable bucket tooth as well as to present a disclosure of the use of the replaceable bucket tooth or a bucket tooth arrangement in an excavator or mining bucket.

[0018] SUMMARY It is an object of the invention to provide a replaceable bucket tooth, which comprises at least one steel material. The at least one of the steel material(s) is a first powder metallurgical (PM) steel comprising 2-45 Vol% hard phase particles. The hard phase particles comprise at least one of carbides, nitrides and carbonitrides. At least 80 % of the hard phase particles have a size less than 20pm, and at least 50 % of the material have a size in the range of 1-10 pm, based on the total amount of carbides. Preferably, at least 50%.

[0019] In one embodiment of the invention, at least 40% of the hard phase particles are vanadium rich carbides, nitrides and / or carbonitrides.

[0020] In another embodiment, the first powder metallurgical steel has a surface hardness of SO- 72 HRC.

[0021] In another embodiment, the powder metallurgical material in the replaceable bucket tooth is a powder metallurgical HIP.ed material.

[0022] A replaceable bucket tooth according to the invention can be a multi material component, wherein different materials can be used in one or more of a tip, a backend, a top part, a bottom part and a core.

[0023] In one embodiment of the invention, a replaceable bucket tooth is described, wherein the first powder metallurgical steel is more than 10mm thick on average.

[0024] It is a further object of the invention to provide a bucket tooth arrangement comprising a replaceable bucket tooth according to any of the embodiments described herein together with an adapter system.

[0025] It is a further object of the invention to provide a replaceable bucket tooth according to any of the embodiments described herein or a bucket tooth arrangement as described herein to be used in an excavator or mining bucket.

[0026] BRIEF DESCRIPTION OF DRAWINGS Various features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying figures in which like characters represent like parts throughout the figures, wherein:

[0027] Fig. 1A shows an isometric view of a first disclosure of a replaceable bucket tooth.

[0028] Fig. IB shows a top view of the replaceable bucket tooth in Fig 1A.

[0029] Fig. 2A shows an isometric view of a second disclosure of a replaceable bucket tooth.

[0030] Fig. 2B shows an end view of the replaceable bucket tooth in Fig. 2A.

[0031] Fig. 2C shows a cross-sectional view through the replaceable bucket tooth along the section line A-A in Fig. 2B.

[0032] Fig. 3A shows an isometric view of a third disclosure of a replaceable bucket tooth.

[0033] Fig. 3B shows an end view of the replaceable bucket tooth in Fig. 3A.

[0034] Fig. 3C shows a cross-sectional view through the replaceable bucket tooth along the section line B-B in Fig. 3B.

[0035] Fig. 3D shows a side view of the replaceable bucket tooth in Fig. 3A.

[0036] Fig. 4A shows an isometric view of a fourth disclosure of a replaceable bucket tooth.

[0037] Fig. 4B shows an end view of the replaceable bucket tooth in Fig. 4A.

[0038] Fig. 4C shows a cross-sectional view through the replaceable bucket tooth along the section line F-F in Fig. 4B.

[0039] Fig. 4D shows a cross-sectional view through the replaceable bucket tooth along the section line G-G in Fig. 4B.

[0040] Fig. 5A shows an isometric view of a fifth disclosure of a replaceable bucket tooth.

[0041] Fig. 5B shows an end view of the replaceable bucket tooth in Fig. 5A.

[0042] Fig. 5C shows a cross-sectional view through the replaceable bucket tooth along the section line D-D in Fig. 5B.

[0043] Fig. 6A shows an isometric view of a sixth disclosure of a replaceable bucket tooth.

[0044] Fig. 6B shows an end view of the replaceable bucket tooth in Fig. 6A.

[0045] Fig. 6C shows a cross-sectional view through the replaceable bucket tooth along the section line F-F in Fig. 6B.

[0046] Fig. 6D shows an isometric exploded view of the replaceable bucket tooth in Fig.6A.

[0047] DETAILED DESCRIPTION One or more specific embodiments of the present disclosure will be described below. These described embodiments are only exemplary of the present disclosure.

[0048] Present embodiments are generally directed to a replaceable bucket tooth, which replaceable bucket tooth for example can be used with excavating and mining equipment, although not restricted to this field. An example embodiment includes a HIP-fabricated replaceable bucket tooth. The teeth may be used on any equipment where use of bucket teeth is beneficial.

[0049] As used herein, the term metal alloy refers to a metallic material composed of a number of different metallic and / or non-metallic chemical elements, including a primary element and additional elements, wherein carbides and or nitrides and / or carbo nitrides are present within the alloy, as described further below.

[0050] Present embodiments involve a replaceable bucket tooth in which at least one steel material have been used to create a replaceable bucket tooth with increased hardness and wear resistance as compared to previous bucket teeth on the market.

[0051] Fig. 1A shows an isometric side view of a first disclosure of a replaceable bucket tooth 1. The replaceable bucket tooth 1 comprises at least one steel material, which at least one steel material is a first powder metallurgical (PM) steel. Fig. IB shows a top view of the replaceable bucket tooth 1 in Fig.lA. In the backend of the replaceable bucket tooth is the adapter area 7 located, which is used to connect the replaceable bucket tooth to the bucket.

[0052] The material used in the bucket teeth must be able to withstand the abrasive and high- impact nature of the materials they interact with, and the teeth will generally wear down due to a combination of abrasive wear, impact wear, thermal wear, corrosive wear, and fatigue wear. These factors collectively contribute to the gradual loss of material, sharpness, and structural integrity of the teeth. The various metal alloys of the bucket tooth may be selected for desirable material properties.

[0053] The replaceable bucket tooth 1 according to the present invention fulfills at least the following conditions: the first powder metallurgical steel preferably comprises 2-45 vol% hard phase particles; the hard phase particles comprise at least one of carbides, nitrides and carbonitrides; at least 80% of the hard phase particles, based on the total amount of carbides, have a size of less than 20 pm; and at least 50% of the hard phase particles, based on the total amount of carbides, have a size in the range of 1-10 pm.

[0054] The size of the hard phase particles is important to the materials properties and can be measured in a microscope. Hard phase particles with a smaller size (less than 5pm) are advantageous when aiming to achieve a material with higher toughness, while hard phase particles of a larger size contributes more to the material's abrasive wear resistance.

[0055] Hard phase particles are formed by the combination of alloying elements (such as chromium, tungsten, molybdenum, vanadium, niobium, and / or titanium) that together with carbon and / or nitrogen form hard compounds. Hard phase particles significantly enhance the wear resistance of steel by providing hard precipitates in the material that resists abrasion and erosion and by increasing the overall hardness of the steel. This is particularly important in high-wear applications as bucket teeth for excavators, mining buckets and the like. For a replaceable bucket tooth, it is important to maintain sharpness of the tooth. By varying the type, size, and distribution of hard phase particles, the mechanical properties of steel can be finely tuned to meet specific application requirements. By selecting and combining materials with different wear-resistant properties in different areas of the tooth, the longevity and effectiveness of the sharp edge for penetration and the surface of the replaceable bucket tooth can be optimized.

[0056] The material will be heat treated so that the surface hardness is 50-72 HRC depending on the specific toughness vs wear resistance that is needed. It is also possible to heat treat the teeth using a special process to get different hardness in different areas of the replaceable bucket tooth. In some embodiments it would for example be beneficial to have a hard tip part of the replaceable bucket tooth that gradually transitions to a softer and tougher backend or adapter area of the replaceable bucket tooth.

[0057] The powder metallurgical material can be a material that has undergone Hot Isostatic Pressing (HIP), i.e. a HIP.ed material. Within the HIP manufacturing process, a HIP process chemically bonds powder metal into a solid part under "extreme" temperature and pressure. One advantage with the HIP process is that it is possible to create unique alloys and material combinations that traditional manufacturing methods cannot achieve.

[0058] For example, after the HIP process has been applied to join the metal powders of the multi- metallic part, the final part may be realized with reduced or no machining time, with little or no welding, and without special overlay and / or heat treatment processes of some traditional manufacturing techniques, thereby reducing manufacturing time and cost relative to traditional manufacturing techniques. Furthermore, the use of a HIP manufacturing process generally provides the capability to efficiently construct pressure-controlling equipment components having a complex shape while avoiding or reducing time-consuming and / or costly complex thermal processing, welding, and / or machining steps.

[0059] The HIP process is preferably a near net shape (NNS) HIP process. Near Net Shape (NNS) HIP is a powder metallurgy manufacturing process in which powdered material is fed into a canister (container) previously manufactured by means of welded sheet metal. The consolidated powder forms the finished or near finished of the component with little or no machining.

[0060] The first PM steel of the present invention will hence be placed into a canister and sealed. The canister is loaded into the HIP vessel and a standard HIP will be performed with parameters adapted to the materials used, where the canister is deformed in a predetermined manner and the inner powder is densified. One example of standard parameters that can be used is a temperature of 900-1250°C, a pressure of 300-3000 bar during a duration of 5 minutes to 10 hours.

[0061] After the Hot Isostatic Pressing is performed a heat treatment will be done by austentizing at 980-1250C depending on alloys used. Quenching is performed using air, gas or oil depending on the cooling rate needed. A double or triple tempering at 500-600°C will be used to achieve the best toughness. The heat treatment is performed to further optimize the mechanical properties and microstructure of the material and will enhance the characteristics such as hardness, strength, toughness, and wear resistance.

[0062] In area(s) exposed to highest wear a high alloyed tool steel will preferably be used. These are tool steels with a high vanadium content giving the excellent abrasive wear resistance. This is due the large volume fraction of V-rich carbides and / or nitrides and / or carbonitrides in the microstructure. The material will have a high hardness due to the carbon and alloying content combined with the formation of hard carbides embedded in a hard martensitic matrix, resulting in an enhanced wear resistance due to the presence of vanadium, tungsten, molybdenum and / or chromium rich carbides, nitrides and / or carbonitrides while still maintaining good toughness as a result of the fine microstructure achieved with the PM HIP process.

[0063] Other types of highly abrasion resistant tool steels with a lower amount and different types of carbides / nitrides and / or carbonitrides than the V-rich steels can also be used. However, steels mainly having Cr-rich carbides are less desirable due to the lower hardness of the Cr- carbides at 900-1500 HV. Alloying with V, the Cr-carbide can reach up to 2000 HV hardness but the V-rich MC carbide or MX carbonitride is significantly harder at 2600-3000 HV. M represents one or more metal atoms; C represents carbon; and X represents a combination of carbon (C) and nitrogen (N). The high alloying content makes the material unsuitable for a casting or forging manufacturing process.

[0064] The first powder metallurgical steel can have different compositions (e.g., a different chemical composition). It is possible to use a first composition of the first metallurgical steel in one part of the tooth and another composition of the first metallurgical steel in another part of the tooth, or another metal alloy. For example, in certain embodiments, the tip 2 of the replaceable bucket tooth 1 may be made of a first powder metallurgical steel, while another part of the replaceable bucket tooth 1 is made of either another composition of the first powder metallurgical steel or of a second steel material, as well be described more in detail with reference to Figs. 2-5 below. In one embodiment the replaceable bucket tooth 1 comprises a first powder metallurgical steel that can be used in a replaceable bucket tooth 1 according to the invention, which first powder metallurgical steel comprises (in weight %):

[0065] Cr 3-15

[0066] Mo 1-10

[0067] V 3-25

[0068] Si 0.1-2

[0069] Mn 0.1-2

[0070] C 2-6

[0071] Optionally

[0072] Co 5-11

[0073] W 0-15

[0074] Balance Fe apart from impurities.

[0075] The first powder metallurgical steel can in some applications also comprise small amounts of Nb and / or Ti, in amounts of 0-0.5 weight-%.

[0076] In some embodiments the replaceable bucket tooth 1 comprises a first powder metallurgical steel that can be used in a replaceable bucket tooth 1 according to the invention, which first powder metallurgical steel consists of (in weight %):

[0077] Cr 3-15

[0078] Mo 1-10

[0079] V 3-25

[0080] Si 0.1-2

[0081] Mn 0.1-2

[0082] C 2-6

[0083] Optionally

[0084] Co 5-11

[0085] W 0-15

[0086] Balance Fe apart from impurities. This first powder metallurgical steel can also be referred to as the primary wear material. It is the main material subjected to wear in the replaceable bucket tooth and is specifically designed to bear the brunt of wear in the replaceable bucket tooth. This embodiment of the first powder metallurgical steel can be used alone or be combined with the broadest definition of the second steel materials, as well as any one of the other proposed example compositions of the second steel materials. Hence, in addition to having the higher wear resistance, the first powder metallurgical steel can also have the function of protecting other materials in the replaceable bucket tooth.

[0087] According to one embodiment, the first powder metallurgical steel can be a composite material having >10 vol.% of added carbides with size larger than 20pm.

[0088] According to another embodiment, at least 40% of the hard phase particles in the first powder metallurgical tool steel are vanadium rich carbides, nitrides and / or carbonitrides.

[0089] Cr contributes to overall hardness and hardenability. Higher levels (above 10%) are typically added for corrosion resistance.

[0090] Mo contributes to overall hardness and hardenability and carbide formation.

[0091] W contributes to overall hardness and hardenability and carbide formation

[0092] V contributes to overall hardness and hardenability and carbide formation. The primary former of carbides giving the high wear resistance. Levels above 20% is not readily manufacturable using conventional gas atomization.

[0093] Si and Mn are added for hardenability and manufacturability and Co for overall hardness and hardenability.

[0094] C contributes to overall hardness, hardenability and carbide formation with carbide formers. The level of carbon must be balanced with the carbide forming elements. Minimum level to ensure the matrix is austenitic at hardening temperature.

[0095] A preferred first powder metallurgical steel that can be used in a replaceable bucket tooth 1 according to the invention, comprises (in weight %): Cr 5-15

[0096] Mo 1-6

[0097] V 9-20

[0098] Si 0.1-1

[0099] Mn 0.1-1

[0100] C 2-4.6

[0101] Optionally

[0102] W 5-13

[0103] Balance Fe apart from impurities.

[0104] In some embodiments, a preferred first powder metallurgical steel that can be used in a replaceable bucket tooth 1 according to the invention, consists of (in weight %):

[0105] Cr 5-15

[0106] Mo 1-6

[0107] V 9-20

[0108] Si 0.1-1

[0109] Mn 0.1-1

[0110] C 2-4.6

[0111] Optionally

[0112] W 5-13

[0113] Balance Fe apart from impurities.

[0114] A more preferred first powder metallurgical steel that can be used in a replaceable bucket tooth 1 according to the invention, comprises (in weight %):

[0115] Cr 5-15

[0116] Mo 1-6

[0117] V 9-15

[0118] Si 0.1-1

[0119] Mn 0.1-1

[0120] C 2.3-4.6

[0121] Optionally Balance Fe apart from impurities.

[0122] In some embodiments, a more preferred first powder metallurgical steel that can be used in a replaceable bucket tooth 1 according to the invention, consists of (in weight %):

[0123] Cr 5-15

[0124] Mo 1-6

[0125] V 9-15

[0126] Si 0.1-1

[0127] Mn 0.1-1

[0128] C 2.3-4.6

[0129] Optionally

[0130] W 5-11

[0131] Balance Fe apart from impurities.

[0132] The total carbide content of the first powder metallurgical steel is preferably above 15%, more preferably 20 %, even more preferably 25 %, even more preferably 30 %.

[0133] The present invention makes it possible to provide a multi material replaceable bucket tooth. This is an advantage since it will be possible to position materials with higher wear resistance and lower toughness in areas where they are needed and materials with lower wear resistance and higher toughness where needed in the replaceable bucket tooth. In this way it will be possible to manufacture bucket teeth with increased operating life and reliability while still being cost effective.

[0134] When more than one material is used for the replaceable bucket tooth 1, each material needed is chosen to provide adequate wear resistance and toughness in the various areas of the replaceable bucket tooth 1 and they need to be possible to heat treat with the same or very similar parameters. One advantage of using different metal alloys in different portions of the part is hence that it is possible to produce a replaceable bucket tooth 1 where the outer layer is hard and resistant to wear, while an inner core is made of a tougher, more resilient material for higher loading force applications. A tip 2 or a tip portion 20 of the replaceable bucket tooth 1 can for example be made of a hard wear-resistant material and a tougher material can be used in the core 6, backend 3 and / or adapter area 7. replaceable bucket tooth 1 according to the invention can hence be a multi material component, wherein different materials can be used in one or more of a tip 2, a backend 3, a top part 4, a bottom part 5 ,a core 6 and an adapter area 7. It is also possible to use the same material in more than one of the different parts of the replaceable bucket tooth 1, as will be described more in detail below with reference to the figures.

[0135] The tip 2 of the replaceable bucket tooth 1 is the front-most part that makes initial contact with the material being excavated, the backend 3 of the replaceable bucket tooth 1 is a rear section of the replaceable bucket tooth where also the adapter area 7 is located, the top part 4 of the replaceable bucket tooth 1 is the area closest to the upper surface of the replaceable bucket tooth, the bottom part 5 of the replaceable bucket tooth 1 is the area closest to the lower surface of the bucket tooth and the core 6 is an internal or central part of the replaceable bucket tooth 1, as shown in the accompanying figures.

[0136] Additionally, by using different metal alloys in different portions of the part, a greater range of material properties (e.g., strength, toughness, ductility, hardness, corrosion resistance) is available compared to the range of material properties achievable using a traditional, single metal alloy bucket tooth with special thermal processing steps or overlay.

[0137] The embodiment having a first powder metallurgical steel can for example be combined with a super martensitic stainless steel (SMSS) or a suitable tool steel (TOS) as a second steel material to manufacture a multi-metallic replaceable bucket tooth. These materials are preferred because they achieve excellent properties through the heat treatment process that has been optimized for the first powder metallurgical steel. The second steel material is preferably also a PM steel.

[0138] By using HIP diffusion bonding to join the first powder metallurgical steel with a super martensitic stainless steel (SMSS) and / or a tool steel (TOS) as the second steel material it is possible to manufacture a multi-metallic replaceable bucket tooth that has appropriate toughness in specific parts of a replaceable bucket tooth, as will be described more in detail with reference to the figures below. The leading edge of the replaceable bucket tooth, i.e. the front, cutting edge of the replaceable bucket tooth that makes initial contact with the material being excavated or moved, is preferably at least 5-10 HRC harder than the adapter area of the replaceable bucket tooth. This edge is critical for the tooth's cutting and penetrating performance, and it is important to avoid chips, cracks, and deformation over time.

[0139] A second steel material which can be used in at least a part of a replaceable bucket tooth 1 comprises (in weight %):

[0140] Cr 3-7

[0141] Mo 0-2

[0142] Si 0.1-2.0

[0143] Mn 0.1-1.0

[0144] C 0.2-0.5

[0145] V 0.1-2

[0146] Nb 0-1

[0147] Nb+V 0.3-2

[0148] Balance Fe apart from impurities.

[0149] This second steel material can be used in combination with any composition of the first powder metallurgical steel and / or with any other of the proposed second steel material.

[0150] A preferred composition of the second steel material which can be used in at least a part of a replaceable bucket tooth 1 comprises (in weight%):

[0151] Cr 4-6

[0152] Mo 1-2

[0153] Si 0.5-1.5

[0154] Mn 0.1-0.5

[0155] C 0.3-0.5

[0156] V 0.2-2

[0157] W 0-6

[0158] Nb 0-1

[0159] Nb+V 0.3-2 Balance Fe apart from impurities.

[0160] A more preferred composition of the second steel material which can be used in at least a part of a replaceable bucket tooth 1 comprises (in weight%):

[0161] Cr 4-6

[0162] Mo 1.1-1.8

[0163] Si 0.5-1.5

[0164] Mn 0.1-0.5

[0165] C 0.3-0.5

[0166] V 0.2-1.5

[0167] W 0-5.3

[0168] Nb 0-0.5

[0169] Nb+V 0.3-2

[0170] Balance Fe apart from impurities.

[0171] A third steel material which can be used in at least a part of a replaceable bucket tooth 1 comprises (in weight %):

[0172] Cr 12.5-17

[0173] Mo 1-3

[0174] Ni 3-8

[0175] Si 0.1-1.0

[0176] Mn 0.2-1.5

[0177] N 0.04-0.14

[0178] C < 0.03

[0179] Optionally

[0180] Cu 0.1-2.0

[0181] Balance Fe apart from impurities.

[0182] A preferred composition of a third steel material which can be used in at least a part of a replaceable bucket tooth 1 comprises (in weight %):

[0183] Cr 12.5-17

[0184] Mo 1-2 Ni 5-8

[0185] Si 0.2-1.0

[0186] Mn 0.2-1

[0187] N 0.04-0.14

[0188] C < 0.05

[0189] Optionally

[0190] Cu 0.1-2.0

[0191] Balance Fe apart from impurities.

[0192] A more preferred composition of a third steel material which can be used in at least a part of a replaceable bucket tooth 1 comprises (in weight %):

[0193] Cr 12.5-17

[0194] Mo 1-2

[0195] Ni 5-8

[0196] Si 0.2-0.7

[0197] Mn 0.2-0.7

[0198] N 0.04-0.14

[0199] C < 0.03

[0200] Optionally

[0201] Cu 0.1-2.0

[0202] Balance Fe apart from impurities.

[0203] This third steel material can be used in combination with any composition of the first powder metallurgical steel and / or with any other of the compositions of the second steel materials. For clarity, any combination of first steel with second and / or third steel is encompassed, including combinations of first and third steel without the second, and first and second steel without the third.

[0204] Additionally, using a HIP manufacturing can enable the manufacturing of surface layers of metal alloy at thicknesses not achievable using weld-based processes (e.g., inlaying, overlaying, cladding) and using metal alloys that are not conducive to welding-based processes. In some embodiments, the at least one steel material may have a defined thickness. In one specific embodiment, the first powder metallurgical steel is at least 10 mm thick, on average. If a HIP manufacturing process is used, thicknesses for the different materials may be independently controlled to any suitable thickness, such as about 3 millimeters (mm) or greater, about 6 mm or greater, about 10 mm or greater, between 3 mm and 25 mm, between 6 mm and 25 mm, about 25 mm or greater.

[0205] The thickness of the different materials can be controlled in any conventional way, including, but not limited to, the use of separating plates between layers of powder to control thickness and prevent mixing of different materials, these plates are typically removed before the HIP process; by using removable filling templates or molds, which creates specific shapes or thicknesses when the powder is added, the templates are then extracted before the container is sealed for HIP processing; the powder can be pre-formed before entering the HIP process, which allows a more precise control over the final shape and thickness, as described in EP 15712980.0; or by filling the powder in distinct layers or levels to create controlled thickness variations.

[0206] As mentioned above, the present invention makes it possible to create a replaceable bucket tooth 1 with different properties in different parts of the tooth by positioning materials of different compositions in different parts of the canister to create a replaceable bucket tooth 1 with high wear resistance and high strength. It could for example be advantageous to have a material with higher wear resistance on one side, i.e. a higher alloyed or harder tool steel on the side of the tooth that is subjected to heavier wear. Another possibility is to use an alloy with higher wear resistance in the center of the tooth to maintain tooth sharpness as wear progresses during use of the bucket. Another way to maintain tooth sharpness is to have a higher hardness at the center of the tooth, which can be accomplished by heat treatment, which will result in a gradual transition of hardness from the surface of the tooth to the center.

[0207] Figs. 2A-2C, 3A-3E, 4A-4C and 5A-5C all show different possible designs, where materials having different properties are placed in different part of the tooth. The designs showed in the figures are not intended to restrict the scope of the invention, but to show that there are several possible designs. The person skilled in the art will understand that also other designs or combination of designs are possible within the scope of the claims.

[0208] Figs. 2A-C shows a second disclosure of replaceable bucket tooth 1, where Fig.2A shows in isometric side view of the tooth 1, Fig. 2B shows an end view and Fig. 2C shows a cross- sectional side view along the section line A-A in Fig. 2B.

[0209] In this second disclosure, a top part 4 of the replaceable bucket tooth 1 comprises a first powder metallurgical tool steel, a bottom part 5 of the replaceable bucket tooth 1 comprises a different first powder metallurgical tool steel than the top part 4 and a backend 3 comprises a second steel material. The first powder metallurgical steel in the bottom part 5 gives a higher wear resistance to the side subjected to heavier wear than the composition of first powder metallurgical steel used in the top part 4, which is less subjected to wear. The adapter area 7 is located in or adjacent to the backend of the replaceable bucket tooth.

[0210] Figs. 3A-D shows a third disclosure of a replaceable bucket tooth 1, where Fig. 3A shows a shows an isometric view of a third disclosure of a replaceable bucket tooth 1, Fig.3B shows an end view of the replaceable bucket tooth 1 in Fig.3A, Fig. 3C shows a cross-sectional view through the replaceable bucket tooth 1 along the section line B-B in Fig.3 B and Fig. 3D shows a side view of the replaceable bucket tooth 1 in Fig.3A.

[0211] In this third disclosure a tip 2 of the replaceable bucket tooth 1 comprising at least one first powder metallurgical tool steel and a backend 3 of the replaceable bucket tooth 1 comprises a second steel material. The first powder metallurgical tool steel requires a higher wear resistance than the second steel material in the backend 3. The adapter area 7 is located in or adjacent to the backend of the replaceable bucket tooth.

[0212] In some embodiments, multiple different variants of the same composition can be combined in different parts of the tooth. For example, several different compositions of the first powder metallurgical steel can be used in the same part of the replaceable bucket tooth 1. steels can be used, for example two or more different compositions of a first powder metallurgical steel can be combined in the tip 2 of the tooth. Figures 3D is provided to show the tooth looks from the other sides of the tooth, the other embodiments herein all have corresponding sides although not shown specifically for each embodiment.

[0213] Fig. 4A-C shows a fourth disclosure of a replaceable bucket tooth 1, where Fig. 4A shows an isometric view of a fourth disclosure of a replaceable bucket tooth 1, Fig. 4B shows an end view of the replaceable bucket tooth 1 in Fig.4A and Fig.4C shows a cross-sectional view through the replaceable bucket toothl along the section line F-F in Fig.4B and Fig. 4 D shows a cross-sectional view through the replaceable bucket tooth 1 along the section line G-G in Fig. 4B.

[0214] In this fourth disclosure, the tip 2 consists of three different areas: a central tip area X made of a first composition of a first powder metallurgical steel, and two side tip areas Y, one on each side of the central tip area X, which side tip areas Y are made of a different composition of a first powder metallurgical steel than the one in the central tip area X. This makes it possible to tailor-make the replaceable bucket tooth 1 even more to withstand the loads in the different parts of the replaceable bucket tooth 1 or customize and specifically designed to meet the unique needs for a specific task.

[0215] A backend 3 of the replaceable bucket tooth 1 comprises a second steel material and / or third steel material. The first powder metallurgical tool steel requires a higher wear resistance than the second / third steel material in the backend 3. The adapter area 7 is located in or adjacent to the backend of the replaceable bucket tooth.

[0216] Fig. 5A-C shows a fifth disclosure of a replaceable bucket tooth 1, where Fig. 5A shows an isometric view of a fifth disclosure of a replaceable bucket tooth 1, Fig. 5B shows an end view of the replaceable bucket tooth 1 in Fig.5A and Fig.5C shows a cross-sectional view through the replaceable bucket tooth 1 along the section line D-D in Fig.5B.

[0217] Ensuring the replaceable bucket tooth's sharpness as it undergoes wear is a critical feature. As the tooth tip rounds off due to wear, its ability to penetrate the bank during digging decreases, particularly in frozen ground conditions. The current cast material is usually not through-hardened, meaning the core is softer than the surface. Consequently, the core wears out faster, making it challenging to maintain a sharp tooth tip. To mitigate this issue, cast teeth are often designed with geometries that encourage a sharper wear pattern. These design features typically involve removing material from the tooth, which could otherwise enhance its lifespan. An alternative solution is to incorporate a more wear-resistant tool steel at the tooth's core, thereby maintaining sharpness as wear progresses.

[0218] In this fifth disclosure a tip 2 of the replaceable bucket tooth 1 comprises a first powder metallurgical steel, a core 6 comprises a first composition of a second steel material and a backend 3 comprises a third steel material. The adapter area 7 is located in or adjacent to the backend of the replaceable bucket tooth.

[0219] Figs. 6A-D shows a sixth disclosure of a replaceable bucket tooth 1, where Fig. 6A shows an isometric view of a sixth disclosure of a replaceable bucket tooth 1, Fig. 6B shows an end view of the replaceable bucket tooth 1 in Fig.6A and Fig.6C shows a cross-sectional view through the replaceable bucket tooth 1 along the section line C-C in Fig.6B. Fig. 6D shows an isometric exploded view of the replaceable bucket tooth of Fig.6A.

[0220] In this sixth disclosure a tip portion 20 of the replaceable bucket tooth 1 removably attached to an intermediate adapter 10. The tip portion 20 is a HIP.ed wear resistant tip portion which can be a multi material part, i.e. according to any of the designs above or any other possible design(s).

[0221] The replaceable bucket tooth 1 is in this disclosure designed with an intermediate adapter 10 between a tooth tip portion 20 and the bucket. The intermediate adapter 10 is an adapter that is mechanically locked to the HIP.ed part of the replaceable bucket tooth 1 and to the excavator bucket. The intermediate adapter 10 contains two adapter areas 7, as can be seen in Fig.6D, one that connects to the HIPed part and another that connects to the bucket, these sections are not shown in the figures. With this embodiment, the tip portion 20, which wears out faster than the intermediate adapter 10, can be replaced, instead of replacing the entire bucket tooth, and thus reduce costs. The intermediate adapter 10 can for example be made of a common cast material used in bucket tooth on the market today, to lower cost, but it would also be possible to use other materials.

[0222] The intermediate adapter can also be used in combination with other embodiments described herein. The embodiment shown in Fig.6D is shows an example of how the intermediate adapter 10 can be locked to the HIPed part (i.e. the tooth tip portion 20 / tip 2) using a central pin that passes through aligned holes in the intermediate adapter 10 and the HIPed part 20;2. Any other way of connecting the two parts to each other can be used.

[0223] The tip portion 20 of this embodiment can be made according to any of the described embodiments for the tip 2. The tip portion 20 can include one or more of the tip 2, the backend 3 the top part 4, the bottom part 5, and the core 6 according to any of the embodiments described herein.

[0224] The tip portion 20 is removably attached to the intermediate adapter 10 in any conventional way.

[0225] The person skilled in the art understands that the examples shown in the drawings are provided as examples and does not cover and limit other possibilities.

[0226] Some further examples, not shown in the drawings, are for example a replaceable bucket tooth 1, wherein a top part 4 and bottom part 5 comprises at least one first powder metallurgical tool steel and a core 6, which core 6 is placed between the top part 4 and bottom part 5, comprises a third material. Another example is a replaceable bucket tooth 1 wherein a top part 4 and a bottom part 5 comprises a first powder metallurgical tool steel, a core 6 comprises a third material and a backend 3 comprises a second steel material. The first powder metallurgical tool steel can be arranged as a shell around the other materials in the replaceable bucket tooth 1.

[0227] Also, other combination of the different powder metallurgical steels, second steel material and / or third steel materials as presented here in is possible. The replaceable bucket tooth 1 according to the present disclosure can further be used together with an adapter system as a bucket tooth arrangement, wherein the adapter system can be a conventional adapter system that enables quick and reliable assembly and disassembly of the replaceable bucket tooth 1 to and from the bucket . The replaceable bucket tooth 1 or the bucket tooth arrangement can further be used in an excavator or mining bucket.

[0228] The adapter area 7 requires not only high strength but also sufficient toughness to cope with the shock loading in this area. The geometry of the adapter area 7 can also make it more sensitive with stress concentrations. Some degree of wear resistance is also required as this area is also subjected to wear although not as severe as the tip portion.

[0229] As mentioned above, the intermediate adapter 10 is not subjected to the same wear as the tooth and do not need to be replaced as often as the teeth. Additionally, by using different metal alloys in different portions of the replaceable bucket tooth 1, a greater range of material properties (e.g., strength, toughness, ductility, hardness, corrosion resistance) is available because it is possible to tailor a material that is suitable for the tip 2 / tip portion 20 which wears out faster and another material that is suitable for the intermediate adapter 10 that has sufficient toughness and strength.

[0230] Materials suitable for the adapter area 7, according to any of the embodiments, are for example hot work tool steels such as for example a Cr, W or Mo type hot work tool steel. One example of a suitable material is Cr-type H13 subjected to a heat treatment cycle optimized for the wear resistant tool steel, although other hot work tool steels is very likely to give adequate properties in temperature ranging from room temperature down to -40°C. Other steel material that can be used is an SMSS, as mentioned above, or a simpler C-steel.

[0231] Wear testing

[0232] The wear resistance of the alloys used in the tip / tip portion of the tooth have been tested in an abrasion test similar to the ASTM G65-16(2021)procedure A wear test. Testing parameters were the same, but a slightly different abrasive sand was used in the test due to availability. The ASTM G65 standard, procedure A, also describes that a reference test can be performed on D2 steel. The results from this shows that the setup according to the invention produces a volume loss within the standard value for D2. However, it is in the lower range.

[0233] The high stress test is performed with the same parameters, except for the distance which is 1 / 3 of the low stress test. The rubber wheel used in the low stress test is replaced by a steel wheel with 150-170 HB hardness in the high stress test.

[0234] The relative performance between the grades is still relevant and the results can be seen in Table 1:

[0235]

[0236] Table 1

[0237] In general, the higher volume content of carbides (more C, Cr, V, Mo and W) and the harder the carbides are the better the wear resistance.

[0238] The alloys described herein for use as material for the replaceable bucket tooth 1 have a significantly higher alloying content as compared to a cast steel. None of the alloys with the very high alloying content considered for the tip of the tooth can be manufactured using conventional metallurgy i.e. they cannot be made using the same casting manufacturing process as is used to day to make bucket teeth.

[0239] Conventional wear-resistant components and methods for producing them generally involve multiple processing stages, each contributing to the overall structure and properties of the final component. Such stages typically include preparation of the body material, filling with raw powders, optional pressing, sintering, hot forging, and in some cases overlay formation and final heat treatment. Each step plays an important role in ensuring the desired characteristics, such as improved wear resistance and good adhesion between the core and body, are achieved in the final product.

[0240] In contrast, the tooth in the present application is manufactured in a single stage combining two or more materials. This places specific requirements on the materials, such as their individual chemistries, so that the interface between the two materials is sound and free from unwanted phases and / or cracks or weak spots. Furthermore, in order to obtain good properties for both materials during heat treatment, the consolidation and heat treatment temperatures of the materials have been carefully investigated, adjusted, and optimized by the inventors to achieve compatibility.

[0241] The latter requirement is the major challenge, since the heat treatment is optimized for the performance of the first alloy(s). This involves a heat treatment temperature that is significantly higher than what is normally recommended for the other alloys. A major issue due to this is that severe grain growth occurs, which generally results in poor properties. However, through the inventors' systematic investigations and development of the material according to the present claims, it was surprisingly found that no, or only very limited, grain growth occurred in these materials. While the disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the following appended claims.

Claims

28CLAIMS1. A replaceable bucket tooth (1), characterized in that the replaceable bucket tooth (1) comprises at least one steel material, wherein at least one of the steel material(s) is a first powder metallurgical steel; wherein the first powder metallurgical steel comprises 2-45 Vol% hard phase particles, wherein the hard phase particles comprise at least one of carbides, nitrides and carbonitrides, wherein at least 80% of the hard phase particles, based on the total amount of carbides, nitrides and / or carbonitrides, have a size of less than 20 pm, wherein at least 50% of the hard phase particles, based on the total amount of carbides, nitrides and / or carbonitrides, have a size in the range of 1-10 pm.

2. A replaceable bucket tooth (1) according to claim 1, wherein at least 40% of the hard phase particles are vanadium rich carbides, nitrides and / or carbonitrides.

3. A replaceable bucket tooth (1) according to claim 1 or 2, wherein the first powder metallurgical steel has a surface hardness of 50-72 HRC.

4. A replaceable bucket tooth (1) according to claim 1, 2 or 3, wherein the at least one steel material is a HIP.ed material.

5. A replaceable bucket tooth (1) according to any of claims 1-4, wherein the first powder metallurgical steel comprises (in weight %):Cr 3-15Mo 1-10V 3-25Si 0.1-2Mn 0.1-2C 2-6OptionallyCo 5-11W 0-15Balance Fe apart from impurities.

6. A replaceable bucket tooth (1) according to claim 5, wherein the total amount of V, Mo, W and Cr is >10 %.

7. A replaceable bucket tooth (1) according to any of the preceding claims, further comprising a second steel material, which second steel material comprises (in weight %):Cr 3-7Mo 0-2Si 0.1-2.0Mn 0.1-1.0C 0.2-0.5V 0.1-2Nb 0-1Nb+V 0.3-2Balance Fe apart from impurities.

8. A replaceable bucket tooth (1) according to any of claims 1-7, further comprising a third steel material, which third steel material comprises (in weight %):Cr 12.5-17Mo 1-3Ni 3-8Si 0.1-1.0Mn 0.2-1.5N 0.04-0.14C < 0.03OptionallyCu 0.1-2.0Balance Fe apart from impurities.

9. A replaceable bucket tooth (1) according to claim 7, which replaceable bucket tooth (1) comprises a tip (2) comprising of one or more materials according to claim 5 and a backend (3) comprising a material according to claim 7.

10. A replaceable bucket tooth (1) according to claim 8, which replaceable bucket tooth (1) comprises a tip (2) comprising one or more materials according to claim 5 and a backend (3) comprising a material according to claim 8.

11. A replaceable bucket tooth 1 according to claim 7, wherein a top part (4) of the replaceable bucket tooth (1) comprises a material according to claim 5, a bottom part (5) comprises a material according to claim 5, but with higher wear resistance than the material in the top part (4) and a backend (3) of the replaceable bucket tooth (1) comprises a material according to claim 7.

12. A replaceable bucket tooth (1) according to claim 8, wherein a top part (4) and a bottom part (5) of the replaceable bucket tooth (1) comprises a material according to claim 5 and a core (6) of the replaceable bucket tooth (1) comprises a material according to claim 8.

13. A replaceable bucket tooth (1) according to claim 8, wherein a top part (4) of the replaceable bucket tooth (1) comprises a material according to claim 5 and a core (6) of the replaceable bucket tooth (1) comprises a material according to claim 8 and a backend (3) of the replaceable bucket tooth (1) comprises a material according to claim 7.

14. A replaceable bucket tooth (1) according to claim 8, which replaceable bucket tooth (1) comprises a tip (2) comprising a material according to claim 5, a core (6) comprising a material according to claim 7 and a backend (3) comprising a material according to claim 8.

15. A replaceable bucket tooth (1) according to claim 7, wherein the replaceable bucket tooth (1) has a tip portion (20) comprising a material according to any of claims 5-7 and an intermediate adapter (10).

16. A replaceable bucket tooth (1) according to any of the preceding claims, wherein the first powder metallurgical steel is more than 10 mm thick on average.

17. A bucket tooth arrangement comprising a replaceable bucket tooth (1) according to any of the claims above and an adapter system.

18. Use of a replaceable bucket tooth (1) according to any of claims 1-16 or a bucket tooth arrangement according to claim 17 in an excavator or mining bucket.

19. A replaceable bucket tooth (1) according to claim 8, wherein the replaceable bucket tooth (1) has a tip portion (20) comprising a material according to any of claims 5-8 and an intermediate adapter (10).

Images