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Abstract

The present invention relates to a work coil for a high-efficiency track link for high-frequency heat treatment and a cooling technology for controlling crystal grain size using the same. The present invention for this purpose is a work coil formed by a structure that surrounds the upper surface and a portion of the left and right sides of a track link, spaced apart at a certain distance, wherein the work coil is integrally formed while including two terminal portions, and includes a transverse portion that is connected to each other while the work coil traverses between each spaced-apart terminal portion, and each terminal portion is extended in the longitudinal direction of the work coil, bent in the left and right side directions of the work coil, extended downward to form a side coil portion, and then connected again to the transverse portion.

Description

Technology Field

[0001] The present invention relates to a work coil for a high-efficiency track link for high-frequency heat treatment and a cooling technology for controlling crystal grain size using the same. Background Technology

[0003] The crawler track chain is designed so that multiple drag shoes are installed in a continuous sequence to support the entire equipment while driving.

[0004] The track shoes are interconnected to the track links, which are mounted on the left and right track shoes respectively to interconnect the track shoes, and the left and right track links are interconnected by connecting pins.

[0005] Since wear resistance, impact resistance, and toughness are required to withstand various fatigue, impact, tensile, and wear loads associated with such track driving environments, material selection and heat treatment conditions are very important.

[0006] In particular, high-frequency heat treatment is typically used during heat treatment. However, in the case of extra-large track links requiring a hardened layer depth of 14 mm or more, if the temperature is heated to 900 degrees or higher to meet the deep hardened layer specifications during operation, the crystal grain size increases, and if the temperature is heated to 900 degrees or lower, it must be heated slowly at low power, which causes a problem of significantly reduced production yield.

[0007] In addition, track links must have an appropriate grain size; if the grain size is low, the bonding strength of the steel material in the track links decreases, making them weak against impact and prone to fracture.

[0008] As an example of public knowledge, Korean registered patent No. 10-1456216, 'Track link coil device for high-frequency heat treatment applied to a high-frequency heat treatment device,' has the objective of the invention to enable uniform heating by forming a stepped step on the first outer horizontal bar and the second outer horizontal bar so that there are no areas where the induced magnetic field sags, and to increase heat treatment efficiency by preventing the coiling phenomenon of the magnetic field at the ends by spacing the silicon steel plates formed on both sides of the first outer horizontal bar and the second outer horizontal bar at a predetermined distance from the first connecting bar and the second connecting bar, and the third connecting bar and the fourth connecting bar.

[0009] However, the example of the above notice contains many problems as follows.

[0010] First, the aforementioned coil device is inefficient, so the burden of exhibition costs is very high when operating continuously at high frequency output.

[0011] Secondly, although iron cores are installed in connecting bars and the like to increase the efficiency of induction heating, the efficiency of the iron cores actually decreases as they absorb the heat generated during high-frequency induction heating. Furthermore, corrosion caused by the cooling water necessitates frequent replacement of the iron cores, resulting in high repair costs for the work coils used in the track links.

[0012] Third, since two independent magnetic fields are generated in the coil device, the product sticks to the work coil of the coil device during continuous high-frequency heat treatment, causing a short circuit, and coil breakage and product defects continue to occur. To improve this, neodymium magnets are installed in a continuous stack on the conveyor that transports the track link to prevent it from sticking to one side of the magnetic field, but the phenomenon of the track link sticking to the coil continues to occur.

[0013] Fifth, in addition to the examples mentioned in the aforementioned notice, the work coils for track links currently used domestically utilize two identical single-winding coils installed on the left and right sides, which generate noise due to vibrations in the coils. This is because the high current flowing through the single-winding coils results in poor coil efficiency, causing the high-frequency heat treatment machine to fail to consume as much power as it supplies. Consequently, vibrations from the high-frequency current cause the coils to break, eventually leading to cracking and damage to the copper pipe around which the coils are wound, and the magnetic field penetrating the installed iron core, causing it to melt.

[0014] Sixth, the work coils currently used for track links consist of two coils, each equipped with an iron core on its upper surface. However, if the efficiency of the iron core in either of the two locations decreases, the magnetic field becomes uneven, causing the high-frequency heat treatment hardened layer to form with severe deviations and resulting in defects. Consequently, there is a problem requiring frequent checks to replace the iron cores on both sides, and the replacement costs are also high.

[0015] Seventh, in conventional high-frequency heat treatment, the grain size is approximately #6. However, while buyers for overseas exports require a grain size of #7 or higher, there is currently no cooling technology capable of controlling the grain size while simultaneously performing high-frequency heat treatment. Prior art literature

[0017] Republic of Korea Registered Patent No. 10-1456216 The problem to be solved

[0018] The present invention, aimed at solving the above-mentioned problems, is intended to provide a high-frequency heat treatment device using a work coil for a high-efficiency track link based on extensive heat treatment experience.

[0019] In addition, another objective of the present invention is to provide a cooling technology capable of controlling grain size. means of solving the problem

[0021] The present invention is a work coil having a structure that is spaced apart at a certain distance and wraps around the upper surface and parts of the left and right sides of a track link, and

[0022] The above work coil is formed integrally while including two terminal sections, and includes a transverse section that is connected to each other while the work coil traverses between each spaced-apart terminal section, and each terminal section is extended in the longitudinal direction of the work coil, then bent in the left and right side directions of the work coil to extend downward, then forms a side coil section, and is connected again to the transverse section.

[0023] In addition, the terminal portion applied in the present invention is characterized by being formed to extend vertically from the upper surface of the track link so as to be connected to power.

[0024] In addition, the work coil applied in the present invention is characterized by being made of a rectangular pipe.

[0025] In addition, the present invention is characterized by the fact that a plurality of support guide bars are installed on the upper and side surfaces of the terminal section, side coil section, and transverse section applied to the present invention, and a support guide plate is further installed to fix the support guide bars at a certain distance apart.

[0026] In addition, according to another aspect of the present invention, a cooling device for controlling crystal grain size using a work coil of the present invention is characterized by comprising a transfer conveyor for a track link, a work coil installed above the transfer conveyor to heat the track link and perform high-frequency heat treatment, a water jacket that transfers the heated track link into the interior for cooling, and a guide bar that aligns the track link left and right and prevents it from deviating when the track link is transferred.

[0027] In addition, the track link applied in the present invention is characterized by being installed to enable forward and backward movement.

[0028] Furthermore, the present invention is achieved through a method for controlling a desired crystal grain size, comprising: a track link heating step in which the track link reaches a temperature state of 900±10 degrees while passing through a work coil oscillating at 1-3 kHz; a slow cooling step in which the heated track link is cooled to a temperature of the A2 transformation point state while being transported; and a rapid cooling step in which the track link that has undergone the slow cooling step is rapidly cooled while passing through a water jacket. Effects of the invention

[0030] According to the present invention, by improving the structure of a conventional work coil, the effect of reducing frequent replacement costs due to power loss, vibration, noise, and damage is achieved. That is, since no iron core is mounted at all on the upper part of the work coil for a track link, there can be no heating unevenness even when heated for a long time, and the lifespan of the work coil is also at least five times longer than that of a conventional track link coil.

[0031] Specifically, conventional work coils, which are fundamentally inefficient, generate excessive output, and since high-frequency heat treatment devices typically perform most operations with an output of about 80-95%, power loss due to excessive output must be accepted; however, the structure of the work coil according to the improved invention can reduce wasted power loss.

[0032] Furthermore, conventional work coils have problems such as short circuits caused by the product and the work coil sticking together, noise generation due to vibration of the work coil, and insufficient induction heating effect on the product even when the output is increased to the maximum. However, since the work coil of the present invention induces heat in proportion to the increase in output, it is possible to achieve the same hardened layer depth even at a slightly lower output compared to existing work coils, and it is possible to reduce electricity costs by more than 15%. Brief explanation of the drawing

[0034] FIG. 1 is a drawing showing a track link among products heat-treated at high frequency through a work coil according to the present invention. FIG. 2 is a series of drawings showing each cross-sectional view and high-frequency heat treatment pattern of a track link applied as an example to the present invention. FIG. 3 is a plan view, front view, and side view of a work coil according to the present invention. Figure 4 is a diagram showing the formation of a magnetic field during high-frequency heat treatment of a work coil. FIG. 5 is a drawing showing the application of the work coil applied in the present invention. FIG. 6 is a drawing showing the state of actually performing high-frequency heat treatment through a work coil according to the present invention. FIG. 7 is a cooling device applied to the present invention. FIG. 8 is a drawing showing the pressure injection part of the cooling device according to the present invention. Figure 9 is a drawing showing the state of high-frequency heat treatment by heating the track link without mounting an iron core. Specific details for implementing the invention

[0035] Hereinafter, preferred embodiments according to the present invention will be described in detail.

[0036] FIG. 1 is a drawing showing a track link among products heat-treated at high frequency through a work coil according to the present invention, FIG. 2 is a drawing showing each cross-sectional view and high-frequency heat treatment pattern of a track link applied as an example to the present invention, FIG. 3 is a plan view, front view, and side view of a work coil according to the present invention, and FIG. 4 is a drawing showing the formation of a magnetic field during high-frequency heat treatment of the work coil.

[0037] First, as an example of FIG. 1, the track link (20) applied to the present invention has left and right track links installed by means of connecting pins, and the upper and side surfaces of the track link (20) on which a track shoe (not shown) is installed are heat-treated to a certain depth, and the state of the heat treatment is specifically illustrated in FIG. 2.

[0038] To perform high-frequency heat treatment of the track link (20) shown in FIGS. 1 and 2, the work coil (10) shown in FIGS. 3 and 4 is applied.

[0039] The work coil (10) applied in the present invention is a work coil (10) formed to wrap around the upper surface and a portion of the left and right sides of the track link, and the work coil (10) is formed integrally while including two terminal portions (12a) (12b), and includes a transverse portion (13) that is connected to each other while the work coil (10) traverses between each spaced terminal portion, and each terminal portion (12a) (12b) is extended in the longitudinal direction of the work coil (10), then bent in the left and right side direction of the work coil (10) and extended downward to form side coil portions (14a) (14b) and then connected again to the transverse portion (13).

[0040] The longitudinal direction described in this invention is the horizontal direction as identified in the drawings, and is a direction in which the length is relatively longer than the vertical direction.

[0041] Furthermore, the track link (20) applied to the present invention is installed in the longitudinal direction during high-frequency heat treatment according to the present invention, and performs high-frequency heat treatment while moving through the conveyor described later.

[0042] Each terminal section (12) is a +, - terminal connected to a high-frequency heat treatment device according to the present invention and is extended in a direction opposite to the track link (20) so as to be applicable to power connection and various sizes and types of high-frequency heat treatment products.

[0043] Meanwhile, to describe the work coil (10) in its entirety, for example, each vertical terminal section (12a) (12b) located on the upper surface is extended horizontally in the opposite direction from where each terminal section (12a) (12b) starts, and then forms a horizontal coil section (11) and is finished. From the part where the horizontal coil section (11) is finished, it is bent downward at 90 degrees to form a single unit, then extended again in the direction of each terminal section (12) to form a side coil section (14a) (14b), and from the part where the extended side coil section (14a) (14b) is finished, it is bent upward at 90 degrees again and is formed in a shape connected to a transverse section (13).

[0044] The transverse section (13) applied in the present invention divides each terminal section (12a)(12b) into different locations, and in particular, the first transverse section (13a) among the transverse sections (13) is located in the center of the work coil (10).

[0045] Additionally, each terminal section (12) is positioned at a spaced-apart and staggered relative to the first transverse section (13a), and the track link (20) is positioned between the side coil sections (14a) (14b) of the work coil (10) and at the lower part of the horizontal coil section (11) extended from each terminal section (12a) (12b) during high-frequency heat treatment work, and since the structure is open between the side coil sections (14a) (14b) overall, the track link (20) is transported between the open side coil sections (14a) (14b).

[0046] Continuing, FIG. 4 is a diagram showing the formation of a magnetic field during high-frequency heat treatment of a work coil. As shown in FIGS. 1 to 4, when power is applied to perform high-frequency heat treatment, the magnetic field starts from the terminal portion (12a) on one side, for example, the + terminal, passes through the side coil portion (14a) and the transverse portion (13) on one side, passes through the side coil portion (14b) on the other side, and enters the - terminal. Since the power is AC power, a magnetic field is repeatedly formed in the coil link (10).

[0047] Meanwhile, the shape of the coil link (10) is such that when the coil makes one cycle and returns to the starting point by turning in the same direction, it becomes a 2-turn coil, so a large magnetic field is formed in the bent part during high-frequency oscillation.

[0048] This track link (20) is located at the center of the magnetic field, and is advantageous for preventing a short circuit caused by the phenomenon in which the work coil (10) and the track link (20) stick together and push each other towards the center of the magnetic field due to the force of the work coil (10) pushing the track link (20).

[0049] As illustrated in FIG. 5, the above operation is such that the transverse section (13) connected to each terminal section (12a) (12b) has a high-frequency induced magnetic field angle such as the magnetic field axis AA and magnetic field axis BB, which are each side coil section (14a) (14b).

[0050] The magnetic field axes AA and BB intersect, generating a strong magnetic flux at C, which is the high-frequency heat treatment area of ​​the track link (20). This magnetic flux allows a deep hardened layer to be obtained on the track link (20) without using an iron core applied in the conventional technology.

[0051] In addition, when high-frequency oscillation occurs, the transverse section (13) pushes the magnetic field downward, and due to this magnetic field, the track link (20) is attached to the bottom of the conveyor described later and stably holds the track link (20).

[0052] In particular, the side coil sections (14a) and (14b) serve to collect the magnetic field, creating a magnetic field center axis that traverses the entire area, and a large magnetic field is created horizontally at the center of the high-frequency hardening section of the track link (20), so that the track link (20) is heated without shaking.

[0053] The magnetic field generated in this way presses down on the track link (20), and the left and right side coil sections (14a) (14b) push the track link (20) with the magnetic field to keep it centered, allowing it to work without shaking in the center. The work coil (10) induces the energy generated by the high-frequency heat treatment device entirely into the track link (20), thereby reducing vibration of the work coil (10), minimizing noise generation, and producing a groundbreaking effect in reducing electricity costs.

[0054] In addition, FIG. 5 is a drawing of a work coil applied to the present invention. As shown in FIG. 5, the work coil (10) is made of a rectangular pipe, and a plurality of support guide bars (30) are installed on the upper and side surfaces of the terminal section (12a)(12b), side coil section (14a)(14b), and transverse section (13), and a support guide plate (32) is further installed to fix the support guide bars (30) at a certain distance apart.

[0055] The support guide bar (30) combines the terminal portion (12a)(12b), the side coil portion (14a)(14b), and the transverse portion (13) to be integral with the support guide plate (32), and prevents the support guide plate (32) from shaking by connecting the terminal portion (12a)(12b), the side coil portion (14a)(14b), and the transverse portion (13).

[0056] FIG. 6 is a drawing showing the state of actually performing high-frequency heat treatment through the work coil according to the present invention, showing that an iron core is not applied to the work coil (10) according to the present invention. FIG. 6 (b) is a side view, showing that even when heating by generating high-frequency oscillation without fixing the track link (20) which is the object to be heated, the track link (20) does not move and is heated well.

[0057] FIG. 7 is a cooling device applied to the present invention. As illustrated, the cooling device (40) for controlling the crystal particle size using a work coil (10) according to the present invention comprises a transfer conveyor (42) for a track link, a work coil (10) installed above the transfer conveyor (42) to heat the track link (20) and perform high-frequency heat treatment, a water jacket (44) that cools the heated track link (20) by transferring it inside, and a guide bar (46) that aligns the track link (20) left and right and prevents it from deviating when the track link (20) is transferred.

[0058] The above-mentioned transfer conveyor (42) is structured such that a track link (20) is installed and transferred in conjunction with the operation of the transfer conveyor (42).

[0059] Additionally, the water jacket (44) is installed on the conveyor (42), but is structured to be transportable in the forward and reverse directions relative to the direction of travel of the conveyor (42).

[0060] The guide bar (46) is also installed on the outer side of the transfer conveyor (42) and performs the role of supporting and guiding both sides of the track link (20), thereby helping the track link (20) move more safely.

[0061] The water jacket (44) applied in the present invention minimizes the effect of the heat-affected layer, which inevitably undergoes annealing during heat treatment.

[0062] Typically, the cooling water jackets used in conventional track link high-frequency heat treatment currently applied in Korea are manufactured and used with a size sufficient to cool only the high-frequency area.

[0063] When cooling with such a cooling water jacket, heat flow is transferred to the track link body during cooling, creating significant annealing—in other words, a heat-affected zone, a term used in heat treatment.

[0064] Since this heat-affected layer has low hardness, it degrades to the material hardness of the track link, resulting in a hardened layer on the surface situated on top of a layer with low material hardness.

[0065] These results occur when working on rocky mountains such as mines, where the entire load of heavy equipment is borne by a part of the track link when stepping on sharp or pointed rocks. As a result, the high-frequency hardened layer on the surface of the track link cracks, and the high-frequency hardened layer peels off from the heat-affected layer located underneath due to delamination.

[0066] In order to minimize the heat-affected layer having the above-mentioned problems, the present invention allows for cooling at a location 50% or more below the height of the track link so that cooling occurs in all directions, and thus heat energy does not move downward during cooling, thereby minimizing the formation of the heat-affected layer.

[0067] More specifically, as shown in FIG. 8, the present invention is equipped with a pressure injection unit (45) that uniformly equalizes the pressure at which cooling water is injected into the interior of the water jacket (44) and ultimately induces the injection of cooling water at the same pressure.

[0068] As mentioned above, since cracks typically occur mostly due to uneven cooling during heat treatment, if the pressure of the quenching water sprayed through the cooling water spray holes is made uniform, the occurrence of cracks and deformation is significantly reduced.

[0069] To this end, as shown in FIG. 8, the pressure injection unit (45) includes a pressure plate (45a) and a support unit (45b). In addition to fixing the pressure plate (45a), the support unit (45b) performs the function of appropriately separating the inner surface of the water jacket by a certain distance so that the cooling water injected from the injection hole (44a) collides with the pressure plate (45a) and spreads uniformly in a radial manner.

[0070] Additionally, the coolant is blocked by the pressure plate (45a) and spreads radially, and flows into the water jacket (44). When a certain water pressure is reached overall, the coolant is sprayed through the injection port (44a) at the same pressure.

[0071] When cooling water is supplied without the pressure plate (45a) according to the present invention, high-pressure quenching water is first sprayed through the spray hole (44a), and the cooling speed is fastest in a certain part of the heat treatment object that is in direct contact with the sprayed cooling water, reaching the MS point (martensite starting point) in that certain part, and hardening begins.

[0072] However, areas other than the specific parts that come into contact first do not reach the MS point, causing non-uniformity between the hardened and unhardened structures in the already hardened metal structure. This difference in shrinkage pressure becomes a cause of heat treatment cracks.

[0073] To solve these problems, the present invention can improve irregular cooling conditions by installing a pressure plate (45a) inside the water jacket (44) to induce cooling with similar pressure in all directions.

[0074] Furthermore, the present invention is achieved through a method for controlling the desired crystal grain size, comprising: a track link heating step in which the track link (20) reaches a temperature state of A3 while passing through a work coil (10) that oscillates at 0.5-10 Khz; a slow cooling step in which the heated track link (20) is cooled to a transformation point state of A2 [760 degrees in the case of pure iron] while being transported; and a rapid cooling step in which the track link (20) that has undergone the slow cooling step is rapidly cooled while passing through a water jacket (44).

[0075] Briefly looking at the present invention, track links (20) are aligned and supplied in a line through a transfer conveyor (42), continuously heated through a work coil (10), and then passed through a water jacket (44) to continuously perform heat treatment and cooling.

[0076] Most high-frequency heat treatments obtain a martensite structure by cooling immediately after heating, but for products requiring a deep hardened layer, the surface heating temperature inevitably rises even when working at a low frequency of 0.5-3 kHz, making it difficult to resolve this issue with current domestic processes.

[0077] However, the present invention aims to solve the above problems. That is, the basic heat treatment method is to heat steel to A3 or higher to transform it into a 100% austenite structure and dissolve carbon, and then bring the dissolved carbon to room temperature through rapid cooling.

[0078] In the case of specifications requiring a high-frequency heat treatment depth of 14 mm or more, the temperature inevitably rises above 900 degrees. However, if the temperature is lowered and heated slowly, production yield decreases, and if the material is heated in the air for a long time, a problem arises where a large amount of oxide scale forms on the surface.

[0079] For this reason, the reality is that extra-large track links in the domestic heavy equipment industry are currently being produced with a grain size of approximately #6.

[0080] The heating temperature applied in this invention is heated to a maximum of 940 degrees or less, and the track link is moved to provide a heating time sufficient to satisfy the hardened layer depth. This high-frequency heat treatment device uses a work coil oscillating at 0.5-3 kHz to induce a large magnetic field in the track link without using an iron core, thereby heating the core of the workpiece. This is a heat treatment technique that can obtain a deep hardened layer without significantly raising the surface material temperature.

[0081] The heated track link is continuously moved along the conveyor (42) and enters the cooling water jacket. At this time, when the temperature to be cooled reaches the A2 transformation point [760 degrees in the case of pure iron], the heat treatment is finished by rapid cooling.

[0082] While high-frequency heat treatment is typically performed by rapidly cooling immediately after heating is finished, the reason the present invention selects the A2 transformation point temperature is to utilize this advantage to cool, as steel shrinks rapidly at 760 degrees [A2 transformation point].

[0083] As the heating temperature of steel increases, its volume expands, but it contracts rapidly at the A2 transformation point [760 degrees]. When steel is heated and its temperature rises, the grain size increases as the temperature rises. When the steel is rapidly cooled to room temperature while in a greatly expanded state, the result is that the grain size becomes #7 or smaller.

[0084] The principle of the present invention is a cooling method in which the track link (10) is heated to approximately A3 and then cooled by lowering the temperature to 760 degrees [A2 transformation point] without immediately cooling. This means that the material shrinks rapidly, which implies that the crystal grain size is reduced. By performing ultra-rapid cooling in the shrunken state to create a martensite structure, cracks and deformation are prevented, and a result with a crystal grain size of #7 or higher is obtained. The A2 transformation point [760 degrees in the case of pure iron] may vary slightly depending on the composition of the material.

[0085] In the present invention, the track link (10) must be heated to A3 or higher to dissolve carbon in a 100% austenite structure and attempt rapid cooling at the A2 transformation point.

[0086] If the temperature is raised to the A2 transformation point [760 degrees] from the beginning and then cooled, the resulting product will have undissolved pearlite and ferrite structures remaining within the martensite structure, which will produce a product with significantly reduced impact or tensile strength.

[0087] In the process of making the crystal grain size #7 or larger according to the present invention, a gap is provided in the water jacket to allow cooling at the A2 transformation point [760 degrees] on a transfer conveyor that continuously performs high-frequency processing on a track link of approximately 900 degrees. The track link is moved forward and backward in the direction of the work coil, positioned in a section where the temperature drops to the A2 transformation point according to the size of the track link, and cooling is started.

[0088] In addition, since the time it takes for the temperature to drop varies depending on the size of the track link, a water jacket is installed at the point where the A2 transformation point [760 degrees] is reached, and cooling water is constantly sprayed to rapidly cool the track link entering the water jacket continuously, thereby performing high-frequency heat treatment.

[0089] Meanwhile, since the A2 transformation point is 760 degrees for pure iron, the A2 transformation point temperature varies slightly depending on the material or composition of the steel material used in the track link.

[0090] In other words, just as the melting point decreases as the amount of impurities increases, the transformation point also decreases as the amount of impurities increases. Therefore, the optimal temperature can be found by sampling materials used between 690 and 750 degrees, and through this sampling process, a grain size of #7 or higher can be obtained.

[0091] By performing such sampling operations at 750°C, 740°C, 730°C, and 720°C in increments of 10°C, the temperature that produces the best crystal grain size can be found. Through the experiments of the present invention, on average, when processed by ultra-rapid cooling at 740°C, the crystal grain size result was obtained as #7 to #10.

[0092] The present invention may be practiced in various other forms without departing from its spirit or principal features. Accordingly, the foregoing embodiments are merely examples in all respects and should not be interpreted restrictively. The scope of the present invention is defined by the claims and is not restricted by the text of the specification. Furthermore, all variations or modifications falling within the equivalent scope of the claims are within the scope of the present invention. Explanation of the symbols

[0094] 10: Work Coil 20: Track Link 30: Support guide bar 40: Cooling device

Claims

Claim 1 A work coil is formed with a structure that surrounds the upper surface and parts of the left and right sides of a track link, spaced apart at a certain distance; the work coil is formed by extending vertically from the upper surface of the track link to connect power, and is formed integrally while including two terminal sections to oscillate at 0.5-10 kHz; the work coil is formed by traversing between the spaced-apart terminal sections and includes a transverse section that connects to each other; each terminal section extends in the longitudinal direction of the work coil, is bent toward the left and right sides of the work coil to extend downward, forms a side coil section, and then connects to the transverse section; the transverse section divides each terminal section into different positions; the first transverse section is located in the center of the work coil, and each terminal section is spaced apart from the first transverse section and located at staggered positions; during high-frequency heat treatment, the track link is structured so that the space between the side coil sections of the work coil is open, and the track link is transported through the open side coil sections to be heated to a temperature state of A3, and as the heated track link is transported, it is slowly cooled to the A2 transformation point state. A work coil for a high-efficiency track link for high-frequency heat treatment, characterized by comprising a water jacket that cools a slow-cooled track link by transferring it internally, a guide bar that aligns the track link left and right during transfer and prevents it from deviating, and controls the crystal grain size through high-frequency heat treatment, wherein a pressure injection unit is installed on the inner surface of the water jacket, the pressure injection unit includes a pressure plate and a support unit, the support unit serves to fix the pressure plate and is spaced a certain distance from the inner surface of the water jacket to ensure uniform radial spreading after colliding with the pressure plate, the water jacket is installed to enable forward and backward movement, a plurality of support guide bars are installed on the upper and side surfaces of the terminal part, side coil part, and transverse part, and a support guide plate is further installed to fix the support guide bars at a certain distance.

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