Ultra-deep induction curing for trackpads

Abstract

This specification discloses an exemplary trackpad (112) having a ground contact portion (202) for use with a track-based machine (100) to propel and support the machine (100) across a support surface. The trackpad (112) may be a trackpad (112) that forms a link in a chain forming a track (102) for the track-based machine (100). The trackpad (112) includes a cast body (114) formed of a first alloy steel having a first strength and toughness. The trackpad (112) includes a roll path (116) that contacts the rollers (502) of the track-based machine (100). The roll path (116) is hardened through an induction hardening process to achieve a hardness level at a depth of 32 millimeters or more from the surface of the roll path (116). The roll path (116) is shaped and positioned to contact the roller (110) of the track drive assembly, thereby reducing wear and fatigue on the trackpad (112) as a result of the contact and force transmitted through the roller (502).

Description

Technical Field

[0001] The present disclosure relates to a hardening process for tracks for track-type machines. More specifically, the present disclosure relates to a track having a roller path that is induction hardened to a depth exceeding twice the typical depth by using an ultra-deep induction hardening process.

Background Art

[0002] Track-type machines are widely used in construction, mining, forestry, and other similar industries. The undercarriage of such track-type machines utilizes a track assembly rather than wheels to provide ground-engaging propulsion. Such track assemblies may be preferred in environments where generating sufficient traction is an issue, such as those frequently found in the industries described above. Specifically, rather than rolling on a working surface with wheels, a track-type machine moves around one or more rotatable track engagement elements, such as drive sprockets, idlers, tensioners, and rollers, and utilizes one or more track assemblies that include an endless loop of ground-engaging track shoes and coupling track links that define an outer surface and support an inner surface.

[0003] Typical track chain assembly designs include track pins fixedly or rotatably coupled to a pair of chain links, and bushings rotatably positioned between the links and around the track pins. Such track chain assemblies can operate in very harsh environments where track joints can be exposed to various abrasive mixtures of water, dust, sand, rock, or other minerals or chemical elements. For heavy machines such as electric rope shovels, track pads that incorporate the track rails and track shoes into a single integrated body are used.

[0004] A track chain assembly may include multiple crawler shoes connected end-to-end via pins to form an endless loop. The endless loop of crawler shoes may be wound around a corresponding drive wheel, one or more idler wheels, and at least one roller. The drive wheel may engage with the pins (or bushings housing the pins) and with the drive lugs or other features of the crawler shoe, thereby transmitting torque from the engine to the track assembly. The idler wheels and rollers may guide the track assembly in a substantially elliptical trajectory around the drive wheel. A tensioner may be positioned between the idler wheel and the drive wheel to push these components apart, thereby maintaining the desired tension of the track assembly. The crawler shoes may function to transmit torque from the drive wheel to the ground surface as a drive linear (traction) force. The weight of the machine may be transmitted from the drive wheel, idler wheel, and roller to the ground surface through the crawler shoes as a bearing force.

[0005] For example, U.S. Patent No. 10,669,602 ('602 patent) describes a manufacturing process for a component subject to wear. The process involves depositing a cladding layer having a thickness greater than 0.5 mm onto a steel body of the component. The steel body is described to have a hardness of about 43 HRC to about 60 HRC using a hardening process. The hardening process involves heat-treating the component to austenitize it, and then quenching it in a liquid bath. After heating, the component may be tempered after being removed from the liquid bath. In one embodiment, the '602 patent includes a track shoe for a track-type machine. However, the addition of additional material (cladding) to the component increases the processing time of the crawler shoe (e.g., trackpad), as well as increasing complexity and cost. The interfaces between the drive wheel, idler wheel, and roller described in the '602 patent may encounter high contact stresses that lead to typical trackpad galling failure.

[0006] The exemplary embodiments of this disclosure are intended to overcome the aforementioned shortcomings. [Overview of the project]

[0007] In exemplary embodiments of the present disclosure, one general aspect includes a track system for a track-based machine. The track system includes a chassis that supports the track-based machine. The system also includes a sprocket coupled to the chassis and driven by a motor and rollers coupled to the chassis. The system also includes a set of track pads that form an infinite loop around the chassis, with adjacent track pads coupled through bushings, and the track pads of the set of track pads may include a body made of alloy steel having a first surface configured to contact a support surface and a second surface configured to contact a roller, the body being made by at least induction hardening the second surface to a hardness of at least 50 HRC to a depth of 32 millimeters from the second surface.

[0008] The implementation may include one or more of the following features: The alloy steel may contain, by weight percent, carbon in the range of 0.30 to 0.40 percent, manganese in the range of 0.80 to 1.30 percent, nickel in the range of 1.00 to 1.70 percent, chromium in the range of 0.80 to 1.30 percent, and molybdenum in the range of 0.20 to 0.80 percent. The cross-sectional thickness of the trackpad from the first surface to the second surface may be in the range of 250 mm to 400 mm. The body may be induction hardened to a depth of at least 10 percent of the cross-sectional thickness to a hardness in the range of 50 HRC to 60 HRC. The trackpad may have a mass in the range of 1000 to 2000 kilograms. The induction hardening of the main body may include setting the fixture distance between the induction coil and the second surface to a target distance, performing two or more preheating induction passes using the induction coil with a first set of parameters, performing an austenization pass using the induction coil with a second set of parameters, hardening the second surface with a polymer hardening material, and tempering the main body after hardening. The fixture distance may be in the range of 4 mm to 7 mm. The first set of parameters may include induction power in the range of 170 kW to 200 kW, induction frequency in the range of 300 Hz to 700 Hz, scanning speed in the range of 60 mm / min to 90 mm / min, and a maximum surface temperature of 1000 degrees Celsius. A second set of parameters may include an induction power in the range of 170 to 200 kilowatts, an induction frequency in the range of 300 to 700 hertz, a scanning speed in the range of 55 millimeters / min to 70 millimeters / min, a maximum surface temperature of 1000 degrees Celsius, a minimum temperature of 820 degrees Celsius at a depth of 32 millimeters from the second surface, and a flow rate of polymer quenching material in the range of 20 cubic meters / hour to 30 cubic meters / hour. The polymer quenching material may contain polymer at a concentration of at least 10 percent.

[0009] One general embodiment includes a method for forming a trackpad for a track-based machine. The method includes casting a body for the trackpad using alloy steel. The method also includes causing hardening of the body through a heat treatment and quenching process. The method further includes causing induction heat treatment of the roller path of the trackpad by setting the fixture distance between the induction coil and the roller path to at least a target distance; performing two or more preheating induction passes using the induction coil using a first set of parameters; performing an austenization pass using the induction coil using a second set of parameters; quenching the roller path using a polymer quenching material; and tempering the body after quenching.

[0010] One common embodiment includes a trackpad. The trackpad includes a body formed of alloy steel, the body having a first surface configured to contact a support surface and a second surface configured to contact a roller, the body being created by induction hardening on the second surface by at least setting the fixture distance between the induction coil and the second surface to a target distance, performing two or more preheating induction passes using the induction coil with a first set of parameters, performing an austenization pass using the induction coil with a second set of parameters, hardening the second surface using a polymer hardening material, and tempering the body after hardening. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view of a track chain assembly for a track-type machine, which implements a track pad having ultra-deep hardening on a roll path, according to at least one embodiment. [Figure 2] This is a perspective view of a trackpad having ultra-deep hardening according to at least one embodiment. [Figure 3]This is a diagram illustrating a process for curing the roll path of a trackpad, according to at least one embodiment. [Figure 4] A cross-sectional view of a trackpad having an induction component for inductive heat treatment of the trackpad surface, according to at least one embodiment, is shown. [Figure 5] This is a cross-sectional view of a composite trackpad that contacts the rollers of a track chain assembly, according to at least one embodiment. [Figure 6] Another cross-sectional view of a trackpad in contact with a roller of a track chain assembly, according to at least one embodiment. [Figure 7] This flowchart illustrates an exemplary method for curing the trackpad described herein, according to at least one embodiment. [Modes for carrying out the invention]

[0012] References are made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to identical or similar parts. Various embodiments of the present disclosure include track chain members such as track pads, and track chains that may use multiple track chain members according to various embodiments of the present disclosure.

[0013] Figure 1 is a perspective view of a track chain assembly 100 for a track-type machine, which implements a composite trackpad according to at least one embodiment. The track chain assembly 100 may be part of a track-type machine that is supported by a frame and has an engine configured to drive a track-type undercarriage. The track-type machine may be any machine that performs industry-related operations, such as mining, construction, agriculture, or another industry known in the art. For example, the track-type machine may be a material handling machine such as a front excavator, rope excavator, hydraulic excavator, dozer, loader, or another material handling machine.

[0014] The track chain assembly 100 includes a chassis frame 104 that supports a drive wheel 106, an idler wheel 108, and rollers 110. The chassis frame 104 may include various components or elements for supporting different components of the track-type machine. The drive wheel 106 can be driven by the engine of the track-type machine to rotate the track chain 102 around the chassis frame 104, thereby propelling the track-type machine.

[0015] The track chain 102 is coupled to the undercarriage frame 104 in a conventional manner. The track-type machine may include multiple track chains 102 for propelling the track-type machine. The track chain 102 includes, among other components, multiple coupled track pads 112 that form an endless loop extending around a drive wheel 106, an idler wheel 108, and a roller 110. The roller 110 is also mounted on the undercarriage frame 104 to support the track-type machine and the guide track chain 102.

[0016] The unique design of the track chains 102, as well as the overall track and undercarriage system from which they are part, is intended to enable tracked machinery to operate in certain environments, such as soft ground conditions, without becoming stuck. While the use of excavators or rope shovels in mechanical environments is discussed herein, it should be understood that the machinery may comprise different types of machines. For example, tracked tractors or even semi-tracked machinery are contemplated herein. Furthermore, the machinery may employ conveyors or other types of machinery in which tracks are used for purposes other than ground engagement elements. The machinery may also include several types of hydraulic excavators, bulldozers, diggers, backhoes, etc.

[0017] The trackpad 112 includes a cast body 114 made of an alloy steel such as medium carbon steel, which forms the primary structural portion of the trackpad 112. The cast body 114 includes a contact surface for resting on a support surface and a bushing contact surface for linking the trackpad 112 together within the track chain 102. The cast body 114 also includes a roll path 116. The roll path 116 may contact the rollers of the undercarriage frame 104, as shown and described with respect to Figures 5 and 6.

[0018] In some embodiments, the trackpad 112 may be sized in such a way that certain forming processes are unavailable. For example, the dimensions of the trackpad 112 may exceed a length of 800mm to 3600mm × a width of 300mm to 600mm × a thickness of 250mm to 400mm, which may make it impossible to form through a forging press due to the size constraints of the forging press. In some embodiments, the trackpad 112 may have a mass in the range of 1000 to 2000 kilograms, which may also result in forming and / or hardening processes that can be used for smaller-scale trackpads where the trackpads of the sizes and dimensions described herein are unavailable. Additionally, effective heat treatment and processing to a specific hardness and / or through annealing may be difficult due to the size of the trackpad 112, as it may retain a large amount of heat during processing, making it difficult to harden and achieve the necessary hardness and toughness levels to withstand the forces the trackpad 112 will experience during use.

[0019] In typical trackpads and conventional induction hardening processes, hardness may not extend beyond approximately 17 millimeters. In the embodiments described herein, hardening allows for reaching an ultra-deep level at a depth of approximately 32 millimeters. In conventional trackpads, hardening to a limited depth, such as up to 20 millimeters, can lead to abnormal or unexpected wear. In some embodiments, the depth may be in the range of 20 to 40 millimeters. In typical induction hardening systems, for trackpads, the induction frequency is typically in the range of approximately 1000 to 4000 Hz in conventional processes. To achieve a desired hardness depth and thereby improve the lifespan and wear characteristics of the trackpad, a frequency of approximately 300 Hz may be used in the induction process. Thus, existing induction heating processes may be used with different parameters and settings to achieve hardness at a desired depth. Additionally, the use of induction heating described herein on trackpads having the size and mass characteristics described herein allows for control of surface heating, thereby reducing grain growth in the trackpad material and controlling grain size.

[0020] In one embodiment, induction curing may be carried out at a frequency of 300 Hz to reach the depths shown herein. Thus, for track pads of track-based machinery such as electric rope shovels (ERS), the technologies and systems described herein may enable curing to a depth of 32 millimeters or more from the surface of the roll path 116 to a Rockwell hardness range of 50 C (HRC) to 60 HRC.

[0021] Therefore, the trackpad 112 can be formed from a material that has sufficient toughness to survive harsh environments such as mining, while also being able to withstand the forces applied through the trackpad assembly to support the weight of the track-type machine. For example, the cast body 114 can be formed from hardenable steel having high toughness and impact resistance. In some embodiments, the cast body 114 can be formed from medium carbon alloy steel.

[0022] In some embodiments, the alloy steel may include a medium carbon steel alloy containing carbon in the range of 0.30 to 0.40 weight percent, manganese in the range of 0.80 to 1.30 weight percent, nickel in the range of 1.00 to 1.70 weight percent, chromium in the range of 0.80 to 1.30 weight percent, and molybdenum in the range of 0.20 to 0.80 weight percent. In some embodiments, the alloy steel may include additional elements and / or components not listed herein.

[0023] In some aspects, at least a portion of the present disclosure relates to the formation, creation, and / or manufacture of a track pad 112, its components, and a system such as the track chain assembly 100 and / or track-type machine in which the track pad is used.

[0024] The formation of the track pad 112 may include casting a body for the track pad 112 from alloy steel. The body can be hardened through conventional heat treatment and quenching processes. The body can be processed to improve the hardness, toughness, and / or other properties of the track pad.

[0025] To harden the roll path 116 of the track pad 112, induction hardening of the roll path 116 can be used to improve the wear characteristics of the track pad 112. Induction hardening of the roll path 116 may include setting a fixture distance between induction heating systems (e.g., coils). The fixture distance can be set such that the distance between the coil and the surface of the roll path 116 is in the range of 4 millimeters to 7 millimeters. The coil can be movable parallel to the surface of the roll path 116 while maintaining the fixture distance.

[0026] After the fixture distance is set, the process for curing the roll path 116 further includes performing two or more preheating induction passes over the roll path 116 with the induction coil at the fixture distance. The preheating passes may be performed using a first set of parameters. For example, the preheating passes may include two to five passes of the induction coil. The preheating passes may be performed using an induction coil that provides 170 to 200 kilowatts of power to the roll path 116. In addition, the first parameter may be the frequency of the coil set in the range of 300 to 700 Hz. The coil may move over the roll path 116 at a scanning speed in the range of 60 mm / min to 90 mm / min. In this way, the roll path may be preheated before curing, and the preheating achieves heating to a certain depth from the roll path 116. The surface of the roll path 116 may be maintained below 1000 degrees Celsius during induction preheating.

[0027] Following the preheating pass, the austenization pass and quenching may be performed on the roll path 116 using a second set of induction coils and parameters. The second set of parameters may include induction coils that supply 170 to 200 kilowatts of power to the roll path 116. Additionally, the first and second parameters may be performed at a frequency of the coil set in the range of 300 to 700 Hz. The coils may move on the roll path 116 at a scanning speed in the range of 55 mm / min to 70 mm / min. The surface of the roll path 116 may be maintained below 1000 degrees Celsius during the austenization pass. Additionally, the temperature may be at least 820 degrees Celsius at a depth of at least 32 mm. Quenching after the austenization pass may include quenching the roll path 116 using a polymer quenching material. The polymer quenching material may include a polymer quenching material having a polymer concentration of at least 10 percent within the quenching material. The quenching material can be delivered to the roll path 116 at a rate of 20 cubic meters / hour to 30 cubic meters / hour. In certain embodiments, the quenching polymer can be delivered to the roll path 116 at a rate of 28 cubic meters / hour.

[0028] After the austenuation pass, the trackpad 112 may be tempered, particularly after quenching. Tempering may occur at temperatures up to 180 degrees Celsius. Tempering may occur after a delay of 3 hours following quenching. Additionally, tempering may occur at the tempering temperature for up to 240 minutes.

[0029] After processing the roll path 116, one or more additional surfaces may be processed with respect to the roll path 116 in a manner similar to that described above. For example, a ground contact surface may be processed to provide a hardness depth as described herein, which can increase its hardness and improve the lifespan of the trackpad 112.

[0030] Figure 2 is a perspective view of a composite trackpad showing a roll path 116 according to at least one embodiment. The trackpad 112 of this disclosure may be applicable to any track-type mobile machine. However, the disclosed trackpad 112 may be particularly applicable to larger machines where the forces passing through the track assembly are significant and can affect the lifespan of the trackpad 112. This may be particularly important for expensive 24-hour operating machines where downtime and the cost of replacement trackpads are high for the owner.

[0031] Figure 2 shows a trackpad 112 which may include one or more pairs of spaced-apart links 204 and 206 that are generally parallel to each other. Each link 204 and 206 may include at least one pinhole formed at its end to connect to the links of other trackpads 112, thereby forming a chain. The trackpad 112 may include a ground engagement surface 202. The ground engagement surface 202 may be located on the bottom side of the cast body 114. In this embodiment, the ground engagement surface 202 and links 204 and 206 are integrally formed as a single cast and / or forged component. In other embodiments, links 204 and 206 and the ground engagement surface 202, as well as other components described herein, may be formed separately and joined together as needed by any suitable process known in the art, such as welding and / or the use of threaded fasteners. The ground engagement surface 202 may have any external geometric shape known in the art. For example, the ground engagement surface 202 may generally be plate-like, include transverse ridges or grooves, have openings, and / or include any other features common in the art.

[0032] The cast body 114 includes a roll path 116 positioned above the insert 118. The roll path 116 may be positioned between links 204 and 206. The roll path 116 may define a surface for guiding the rollers of the drive assembly across the trackpad 112. The roll path 116 may include a wear surface that engages with the rollers. The weight of the track-type machine may be transmitted from the rollers through the roll path 116.

[0033] The roll path 116 may be planar, arched, or have any suitable shape for engaging with the roller. For example, the roller may have a curve, and the roll path 116 may be shaped with a similar curve. When the machine is in motion, additional rolling and sliding forces between the roll path 116 and the roller create frictional wear of the roll path 116. Abrasive debris such as gravel, dust, sand, or other ground material may adhere between the roller and the roll path 116, causing additional wear and / or grinding of the roll path 116.

[0034] The roll path 116 may be cured as described herein. Induction curing of the roll path 116 of the trackpad 112 may be used to improve the wear properties of the trackpad 112. Induction curing of the roll path 116 may include setting a fixture distance between induction heating systems (e.g., coils). The fixture distance may be set such that the distance between the coil and the surface of the roll path 116 is in the range of 4 to 7 millimeters. The coil may be movable parallel to the surface of the roll path 116 while maintaining the fixture distance.

[0035] After the fixture distance is set, the process for curing the roll path 116 further includes performing two or more preheating induction passes over the roll path 116 with the induction coil at the fixture distance. The preheating passes may be performed using a first set of parameters. For example, the preheating passes may include two to five passes of the induction coil. The preheating passes may be performed using an induction coil that provides 170 to 200 kilowatts of power to the roll path 116. In addition, the first parameter may be the frequency of the coil set in the range of 300 to 700 Hz. The coil may move over the roll path 116 at a scanning speed in the range of 60 mm / min to 90 mm / min. In this way, the roll path may be preheated before curing, and the preheating achieves heating to a certain depth from the roll path 116. The surface of the roll path 116 may be maintained below 1000 degrees Celsius during induction preheating.

[0036] Following the preheating pass, the austenization pass and quenching may be performed on the roll path 116 using a second set of induction coils and parameters. The second set of parameters may include induction coils that supply 170 to 200 kilowatts of power to the roll path 116. Additionally, the first and second parameters may be performed at a frequency of the coil set in the range of 300 to 700 Hz. The coils may move on the roll path 116 at a scanning speed in the range of 55 mm / min to 70 mm / min. The surface of the roll path 116 may be maintained below 1000 degrees Celsius during the austenization pass. Additionally, the temperature may be at least 820 degrees Celsius at a depth of at least 32 mm. Quenching after the austenization pass may include quenching the roll path 116 using a polymer quenching material. The polymer quenching material may include a polymer quenching material having a polymer concentration of at least 10 percent within the quenching material. The quenching material can be delivered to the roll path 116 at a rate of 20 cubic meters / hour to 30 cubic meters / hour. In certain embodiments, the quenching polymer can be delivered to the roll path 116 at a rate of 28 cubic meters / hour.

[0037] After the austenuation pass, the trackpad 112 may be tempered, particularly after quenching. Tempering may occur at temperatures up to 180 degrees Celsius. Tempering may occur after a delay of 3 hours following quenching. Additionally, tempering may occur at the tempering temperature for up to 240 minutes.

[0038] After processing the roll path 116, one or more additional surfaces may be processed with respect to the roll path 116 in a manner similar to that described above. For example, the ground engagement surface 202 and / or drive lug 120 may be processed to provide a hardness depth as described herein, which can increase their hardness and improve the lifespan of the trackpad 112.

[0039] In the embodiment shown in Figure 2, the trackpad 112 includes a pair of drive lugs 120 positioned on the upper side of the cast body 114, which engage with the drive wheels in the track assembly. The drive lugs 120 may be positioned between links 204 and 206 on either side of the roll path 116. In other embodiments, the drive lugs 120 may be positioned elsewhere on the trackpad 112, and fewer or more drive lugs 120 may be included. The drive lugs 120 may contact the opening, pocket portion, or teeth portion of the drive wheel in the track assembly to receive torque from the engine and provide traction force to the trackpad 112 to move the machine. The drive lugs 120 may have one or more wear surfaces that contact the drive wheel. When the machine is moving, these wear surfaces may experience grinding and wear from the force transmitted by the drive wheel, which can be amplified if abrasive debris gets caught between the drive lugs 120 and the drive wheel.

[0040] In some embodiments, the drive lug 120 may be partially and / or entirely formed from a material having high resistance to wear and abrasion, including high impact strength, tensile strength, and yield strength. In some embodiments, manganese steel may be used for the drive lug 120, for example, an alloy of steel having 10% or more manganese contained therein. In some embodiments, the alloy may have 12-14% manganese steel. In some embodiments, ASTM A128 steel may be used for the drive lug. The manganese steel alloy for the drive lug hardens rapidly in use without increasing brittleness, thereby providing greater wear and abrasion resistance to the sprocket of the track assembly than the cast body 114. In some embodiments, other work-hardening alloys and materials may be used to form the drive lug, including stainless steel and other steel alloys having similar work-hardening properties to manganese steel.

[0041] To withstand bearing forces without cracking or breaking, the drive lugs may be formed from a high-strength metal such as manganese steel. While manganese steel can be cast to produce drive lugs 120 of any suitable shape and dimensions, it may become brittle after casting. Therefore, the drive lugs 120 may be solution-treated to achieve an austenite grain structure within the metal, which improves overall toughness. Before casting, chromium may be added to the manganese steel to promote faster working hardening of the austenitic manganese steel. Because austenitic manganese steel is also soft, the drive lugs 120 may experience plastic deformation during use. Instead of implementing an expensive and time-consuming heat treatment process to harden the cast body 114, the working hardening of the drive lugs 120 may provide the hardness necessary to withstand the forces experienced during use. The drive lugs 120 and / or inserts for the drive lugs 120 may be formed and friction-welded, or otherwise joined to the cast body 114.

[0042] Figure 3 shows a process 300 for curing the roll path 314 of a trackpad 304 according to at least one embodiment. The trackpad 304 may be similar to and / or identical to the trackpad 112, and the roll path 314 may be similar to and / or identical to the roll path 116. To cure the roll path 314 of the trackpad 304, induction curing of the roll path 314 may be used to improve the wear properties of the trackpad 304. Induction curing of the roll path 314 may include setting a fixture distance between the induction heating system 306 and the roll path 314 in step 302. The fixture distance may be set such that the distance between the coil and the surface of the roll path 314 is in the range of 4 to 7 millimeters. The coil may be movable parallel to the surface of the roll path 314 (e.g., along direction 310) while maintaining the fixture distance.

[0043] After the fixture distance is set in step 302, the process 300 for curing the roll path 314 further includes performing two or more preheating induction passes over the roll path 314 in step 308, with the induction coil at the fixture distance. The preheating passes may be performed using a first set of parameters. For example, the preheating passes may include two to five passes of the induction coil. The preheating passes may be performed using an induction coil that provides 170 to 200 kilowatts of power to the roll path 314. In addition, the first parameter may be the frequency of the coil set in the range of 300 to 700 Hz. The coil may move over the roll path 314 at a scanning speed in the range of 60 mm / min to 90 mm / min. In this way, the roll path may be preheated before curing, and the preheating achieves heating to a certain depth from the roll path 314. The surface of the roll path 314 may be maintained below 1000 degrees Celsius during induction preheating.

[0044] Following the preheating pass, process 300 may include in step 312 that an austenization pass and quenching may be performed on the roll path 314 using an induction coil and a second set of parameters. The second set of parameters may include an induction coil that supplies 170 to 200 kilowatts of power to the roll path 314. In addition, the first and second parameters may be implemented at a frequency of the coil set in the range of 300 to 700 Hz. The coil may move on the roll path 314 at a scanning speed in the range of 55 mm / min to 70 mm / min. The surface of the roll path 314 may be maintained below 1000 degrees Celsius during the austenization pass. In addition, at a depth of at least 32 mm from the surface of the roll path 314, the temperature may be at least 820 degrees Celsius.

[0045] Following the austenization pass, in step 316, process 300 may include quenching with a third parameter. Quenching after the austenization pass may include quenching the roll path 314 using polymer quenching material 318. Polymer quenching material 318 may include polymer quenching having a polymer concentration of at least 10 percent in the quenching material. The polymer quenching material may be delivered to the roll path 314 at a rate of 20 cubic meters / hour to 30 cubic meters / hour. In certain embodiments, the quenching polymer may be delivered to the roll path 314 at a rate of 28 cubic meters / hour.

[0046] Following the autosterification pass, the trackpad 304 may typically be tempered in step 320 using a heat source 322 after quenching. Tempering may occur at temperatures up to 180 degrees Celsius. Tempering may occur after a delay of 3 hours following quenching. Additionally, tempering may occur at the tempering temperature for up to 240 minutes.

[0047] After processing the roll path 314, one or more additional surfaces may be processed with respect to the roll path 314 in a manner similar to that described above. For example, a ground contact surface may be processed to provide a hardness depth as described herein, which can increase its hardness and improve the lifespan of the trackpad 304.

[0048] Figure 4 shows a cross-sectional view 400 of a trackpad 402 having an induction component 404 for inductively heat-treating the surface 412 of the trackpad 402, according to at least one embodiment. During the induction heat treatment described herein, the induction component 404 is set at a fixture distance 406 ranging from 4 to 7 millimeters from the surface 412 of the trackpad 402. The induction component 404 is maintained at the fixture distance 406 as the induction component 404 traverses the surface 412 of the trackpad 402 parallel to it (e.g., along direction 408).

[0049] The induction component 404 may be used to induce curing the surface area 410 of the trackpad 402 according to process 300. The surface area 410 may extend to a depth of 32 millimeters or more within the body of the trackpad 402, the depth being measured from the surface 412.

[0050] Figures 5 and 6 provide cross-sectional views of a track pad 112 having a roll path 116 with ultra-deep hardening that contacts a roller 110 of a track chain assembly 100, according to at least one embodiment. The roller 110 includes a roller surface 502 that contacts the roll path 116. The roller 110 is coupled to a chassis frame 104 that supports the weight of the track-type machine. Thus, the roller 110, and therefore the roller surface 502, transmit forces to the roll path 116 and the track pad 112 to support the track-type machine.

[0051] The internal structure of the trackpad 112 may have a variety of geometric shapes, including aisles, rows, holes, protrusions, and various other shapes and configurations. In some embodiments, the composite trackpad 112 has a solid body. In some embodiments, as shown in Figure 6, the trackpad 112 may include a variety of internal geometric shapes. The trackpad 112, more specifically the cast body 114, provides structural support to the trackpad 112, thereby being sized and configured to support a tracked machine.

[0052] Figure 7 is a flowchart showing an exemplary method for curing the trackpad described herein, according to at least one embodiment. The trackpad 112 described herein may be applicable to any track-type mobile machine. However, the disclosed trackpad may be particularly applicable to larger machines where the forces passing through the track assembly are significant and can affect the lifespan of the trackpad. This may be particularly important for expensive 24-hour operating machines where downtime and the cost of replacement trackpads are high for the owner.

[0053] Process 700 may be carried out to produce the trackpad described herein for use in a tracked machine. In 702, Process 700 includes casting a body using alloy steel. The alloy steel may have sufficient toughness to survive harsh environments such as mining, while also being able to withstand the forces applied through the trackpad assembly to support the weight of the tracked machine. For example, the cast body may be formed of a hardenable steel having high toughness and impact resistance. In some embodiments, the cast body may be formed of a medium carbon alloy steel. For example, the cast body may include a medium carbon steel alloy containing carbon in the range of 0.30–0.40 weight percent, manganese in the range of 0.80–1.30 weight percent, nickel in the range of 1.00–1.70 weight percent, chromium in the range of 0.80–1.30 weight percent, and molybdenum in the range of 0.20–0.80 weight percent. In some embodiments, the alloy steel may include additional elements and / or components not listed herein.

[0054] Process 700, in 704, includes uniformly hardening the cast body to a first hardness level. The hardness may be based on the operating environment and / or intended use of the trackpad, but may include directly hardening the cast body.

[0055] In step 706, process 700 may include induction heat treatment (e.g., induction hardening) of the roll path of the cast body. The induction heat treatment process may include sub-processes 708-714 for induction hardening of the roll path. In order to harden the roll path of the trackpad, in step 708, a fixture distance may be set between the induction heating system and the roll path. The fixture distance may be set such that the distance between the coil and the surface of the roll path 314 is in the range of 4 to 7 millimeters. The coil may be movable parallel to the surface of the roll path while maintaining the fixture distance.

[0056] After the fixture distance is set in step 708, process 700 further includes, in step 710, performing two or more preheating induction passes on the roll path with the induction coils at the fixture distance. The preheating passes may be performed using a first set of parameters. For example, the preheating passes may include two to five passes of the induction coils. The preheating passes may be performed using induction coils that provide 170 to 200 kilowatts of power to the roll path. Additionally, the first parameter may be the frequency of the coil set in the range of 300 to 700 Hz. The coils may move along the roll path at a scanning speed in the range of 60 mm / min to 90 mm / min. In this way, the roll path may be preheated before curing, and the preheating achieves heating to a certain depth from the roll path. The surface of the roll path may be maintained below 1000 degrees Celsius during induction preheating.

[0057] Following the preheating pass, process 700 may include in step 712 that an austenization pass and quenching may be performed on the roll path using an induction coil and a second set of parameters. The second set of parameters may include an induction coil supplying 170 to 200 kilowatts of power to the roll path. In addition, the first and second parameters may be implemented at a frequency of the coil set in the range of 300 to 700 Hz. The coil may move along the roll path at a scanning speed in the range of 55 mm / min to 70 mm / min. The surface of the roll path may be maintained below 1000 degrees Celsius during the austenization pass. In addition, at a depth of at least 32 mm from the surface of the roll path, the temperature may be at least 820 degrees Celsius.

[0058] Following the austenization pass, in step 712, process 700 may include quenching with a third parameter. Quenching after the austenization pass may include quenching the roll path using a polymer quenching material. The polymer quenching material may include a polymer quench having a polymer concentration of at least 10 percent in the quenching material. The polymer quenching material may be delivered to the roll path at a rate of 20 cubic meters / hour to 30 cubic meters / hour. In certain embodiments, the quenching polymer may be delivered to the roll path at a rate of 28 cubic meters / hour.

[0059] Following the autosterification pass, the trackpad can typically be tempered in step 714 using a heat source after quenching. Tempering can occur at temperatures up to 180 degrees Celsius. Tempering can occur after a delay of 3 hours following quenching. Additionally, tempering can occur at the tempering temperature for up to 240 minutes.

[0060] After processing the roll path, in step 716, one or more additional surfaces may be processed in a manner similar to that described above for the roll path 314. For example, the ground contact surface may be processed to provide a hardness depth as described herein, which can increase its hardness and improve the lifespan of the trackpad. Finally, in order to prepare the trackpad for assembly by a track-type machine, additional machining and / or finishing may be performed on the trackpad in 718.

[0061] It should be noted that some of the operations of process 700 may be performed in a different order than presented, with additional elements and / or without some elements. Furthermore, some of the operations of process 700 may be performed substantially simultaneously and therefore may complete in a different order than the operations shown above.

[0062] Industrial applicability This disclosure describes systems, structures, and methods for improving the wear resistance and toughness of components, such as components of track-type machinery. These improved components may include track pads used in track chain assemblies of track-based machinery. Track pads as disclosed herein may have roll paths and / or wear surfaces having ultra-deep hardening performed thereon on the contact surface of the track pad. The contact surface may be a surface that contacts the rollers of a track drive assembly for track-based machinery. While track pads and procedures for forming track pads are discussed in the context of track-type machinery and the undercarriages of such track-type machinery, it is naturally possible that track pads and the mechanisms for forming them are applicable across a wide range of mechanical systems, such as any mechanical system that can benefit from improved wear resistance of the contact surface to friction and abrasion in high force transmission regions.

[0063] As a result of the systems, apparatus, and methods described herein, consumable parts of machinery, such as trackpads, may have a longer lifespan. For example, the trackpads described herein may have a longer lifespan than conventional trackpads not formed by the mechanisms described herein. In some cases, trackpads and / or other components may enable a 25% to 400% improvement in the wear life of consumable parts of track-type machinery. This reduces field downtime, decreases the frequency of service and maintenance, and reduces the overall cost of heavy machinery such as track-type machinery. Improved reliability and reduced field-level downtime also improve the user experience, allowing the machinery to dedicate itself to its intended purpose for a longer time and a greater proportion of its overall lifespan. Improved machine uptime and reduced periodic maintenance may enable a more efficient allocation of resources (e.g., fewer but more reliable machines at a construction site). Thus, the technologies disclosed herein improve the efficiency of project resources (e.g., construction resources, mining resources, etc.), provide higher uptime for project resources, and improve the financial performance of project resources.

[0064] While aspects of this disclosure have been specifically shown and described with reference to the embodiments described above, it will be understood that various additional embodiments are intended by modifications of the disclosed machines, systems, and methods without departing from the spirit and scope of the disclosed content. Such embodiments should be understood to fall within the scope of this disclosure as determined by the claims and any equivalents thereof.

[0065] The listing of value ranges in this specification is merely intended to serve as a convenient way to refer individually to the individual values ​​within those ranges unless otherwise specified herein, and each individual value is incorporated herein as if it were listed individually. Unless otherwise specified herein, all methods described herein may be carried out in any suitable order.

Claims

1. A track system (102) for a track-based machine (100), The undercarriage (104) supports the aforementioned truck-based machine (100), A sprocket (106) is coupled to the aforementioned undercarriage (104) and driven by a motor, A roller (110) coupled to the undercarriage (104), The set of trackpads (112) forms an infinite loop around the suspension (104), and adjacent trackpads (112) are connected through bushings (204), and the trackpads (112) of the set of trackpads (112) are A track system (102) comprising a body (114) made of alloy steel, having a first surface (202) configured to contact a support surface and a second surface (116) configured to contact the roller (110), wherein the body (114) is created by at least induction hardening the second surface (116) to a hardness of at least 50 HRC to a depth of 32 millimeters from the second surface (116).

2. The aforementioned alloy steel, in weight percentage, Carbon in the range of 0.30 percent to 0.40 percent, Manganese in the range of 0.80 to 1.30 percent, Nickel in the range of 1.00 to 1.70 percent, Chromium in the range of 0.80 to 1.30 percent, and The track system (102) according to claim 1, comprising a medium carbon steel alloy containing molybdenum in the range of 0.20 to 0.80 percent.

3. The track system according to claim 1, wherein the cross-sectional thickness of the trackpad (112) from the first surface to the second surface is in the range of 250 mm to 400 mm.

4. The track system according to claim 3, wherein the main body (114) is induction hardened to a depth of at least 10 percent of the cross-sectional thickness to a hardness in the range of 50 HRC to 60 HRC.

5. The track system according to claim 1, wherein the trackpad (112) has a mass in the range of 1,000 to 2,000 kilograms.

6. A method for forming a trackpad (112) for a track-based machine (100), Casting the main body (114) for the trackpad (112) using alloy steel, The heat treatment and quenching process causes the main body (114) to harden, at least, Setting the fixture distance (406) between the induction coil (404) and the roller path (116) to the target distance, Using a first set of parameters, two or more preheating induction paths are performed using the induction coil (404). Using a second set of parameters, the austenuation path is performed using the induction coil (404). The roller path (116) is quenched using a polymer quenching material, and A method comprising tempering the main body (114) after quenching, thereby causing induction heat treatment of the roller path (116) of the trackpad (112).

7. The first set of parameters is Inductive power in the range of 170 kilowatts to 200 kilowatts, Induction frequencies in the range of 300 Hz to 700 Hz, Scanning speeds ranging from 60 mm / min to 90 mm / min, The method according to claim 6, comprising a maximum surface temperature of 1000 degrees Celsius.

8. The second set of parameters is Inductive power in the range of 170 kilowatts to 200 kilowatts, Induction frequencies in the range of 300 Hz to 700 Hz, Scanning speeds ranging from 55 mm / min to 70 mm / min, With a maximum surface temperature of 1000 degrees Celsius, The minimum temperature at a depth of 32 millimeters from the roller path at 820 degrees Celsius, The method according to claim 6, comprising a flow rate of the polymer quenching material in the range of 20 cubic meters / hour to 30 cubic meters / hour.

9. Trackpad (112), It comprises a body (114) made of alloy steel, and the body (114) is A first surface (202) configured to contact the support surface, The main body (114) has a second surface (116) configured to contact the roller (110), and the main body (114) has at least, Setting the fixture distance (406) between the induction coil (404) and the second surface (116) to the target distance, Using a first set of parameters, two or more preheating induction paths are performed using the induction coil (404). Using a second set of parameters, the austenuation path is performed using the induction coil (404). The second surface (116) is quenched using a polymer quenching material, and A trackpad (112) is formed by induction hardening of the second surface (116) by tempering the main body (114) after quenching.

10. The trackpad (112) has a mass in the range of 1,000 to 2,000 kilograms. The aforementioned alloy steel, in weight percentage, Carbon in the range of 0.30 percent to 0.40 percent, Manganese in the range of 0.80 to 1.30 percent, Nickel in the range of 1.00 to 1.70 percent, Chromium in the range of 0.80 to 1.30 percent, A trackpad (112) according to claim 9, comprising a medium carbon steel alloy containing molybdenum in the range of 0.20 to 0.80 percent.

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