KR20200089390A - Track bush manufacturing method based on high frequency heat treatment - Google Patents

Abstract

According to the present invention, provided are a track bushing with improved surface hardness, a track bushing manufacturing method based on bore high-frequency thermal treatment and a bore high-frequency thermal treatment apparatus for manufacturing a track bushing. According to the present invention, the track bushing with improved surface hardness, the track bushing manufacturing method based on bore high-frequency thermal treatment and the bore high-frequency thermal treatment apparatus for manufacturing a track bushing have technical characteristics, wherein the generation of a crack is minimized by improving the surface hardness through an increase in carbon content, a reduction in chrome content and the addition of molybdenum, and a hardening thermal treatment is performed on the entire surface of a track bushing material, and then, a high-frequency thermal treatment is performed on the inner circumference surface of the track bushing material, so that a softening section of a core part of the track bushing can be minimized to extend an abrasion lifespan through the area expansion of an outer hardening layer and also the side hardness of the track bushing can be continuously maintained while minimizing side abrasion.

Description

Track bush with improved surface hardness, track bush manufacturing method based on internal high-frequency heat treatment, and internal track high-frequency heat treatment device for track bush manufacturing{Track bush manufacturing method based on high frequency heat treatment}

The present invention relates to a track bush manufacturing method based on a track bush with improved surface hardness, an inner diameter high frequency heat treatment, and an inner diameter high frequency heat treatment device for manufacturing a track bush. More specifically, the surface hardness is improved by increasing carbon content, reducing chromium content, and adding molybdenum. To minimize the occurrence of cracks, and to perform the front hardening heat treatment for the track bushing material, and then perform the high frequency heat treatment for the inner circumferential surface of the track bushing material, thereby minimizing the softening section of the track bush core and expanding the outer hardened layer area. Through this, the track bushing with improved surface hardness can be minimized while the lateral hardness of the track bush is continuously maintained while the wear bushing can be extended while the track bush is manufactured. It is about.

Construction heavy equipment, tanks, and agricultural machinery are often implemented as caterpillars. Such a caterpillar vehicle is driven while the entire weight of the equipment is supported by a caterpillar composed of a track chain in which several parts are continuously connected and assembled.

The track shoes forming the track chain are interconnected by track bolts and nuts arranged in two holes drilled on the left and right sides of the track link, and the track links on the left and right are track pins. ). Here, the track pin is wrapped by a track bush as shown in FIG. 1 to prevent abrasion, and the track bush is manufactured in a tubular shape as the track pin must be inserted therein.

The life of the track chain is greatly affected by the degree of wear on the outer surface of the track bush, which is directly transmitted by the traction force of the sprocket. Accordingly, in order to improve the mechanical properties of the track bush, conventionally, the track bush is manufactured by bore-cutting the inner diameter of a medium carbon low alloy steel (medium carbon + chromium + bronze alloy steel) round bar, or after forming a tube shape through material drawing A track bush was manufactured by performing quenching heat treatment and high frequency heat treatment.

In addition, various heat treatment techniques have been applied to improve the mechanical properties of the track bush. Quenching and tempering heat treatment for the track bushing material, through hardening and tempering for the track bushing material. ) Quenching heat treatment techniques such as heat treatment are applied, and carburizing heat treatment for surface hardening of track bushing materials and high-frequency heat treatment for inner/outer diameter of track bushing materials are also currently applied.

Here, the high-frequency heat treatment for the trackbush material is to rapidly heat the surface of the trackbush material using an induction magnetic field, and then cool it.A soft soft zone (softening section) is formed in the center of the material during heat treatment, and a hardened layer is formed on the inner and outer peripheral surfaces of the material. It is a heat treatment technique. However, in the case of such high-frequency heat treatment, there was a disadvantage that only a relatively shallow cured layer was obtained, and when heat treatment was performed to create a deep cured layer for the purpose of extending the wear life of the outer surface of the track bush, the softening section in the center of the material This spread has resulted in degrading quality.

This leads to premature wear of the outer surface of the track bush that directly receives the traction of the sprocket, and the softening section formed in the center of the material spreads to the side of the track bush, causing abnormal wear when in contact with the track seal. In addition, foreign matter has been introduced into the gap between the track bush and the track pin, causing seizing, and thus it is not expected to improve the quality or increase the life.

Republic of Korea Patent Registration No. 10-0619226 "Method of manufacturing track link bushing for heavy equipment" Republic of Korea Patent Application Publication No. 10-2009-0120325 "Method of manufacturing bush for track link"

Accordingly, the present invention improves the problems of the prior art, and improves the surface hardness through increasing carbon content, reducing chromium content, and adding molybdenum, thereby improving a new type of track bushing with improved surface hardness to minimize crack generation. It is aimed at providing.

In addition, the present invention performs a front hardening heat treatment on the track bushing material and then performs a high frequency heat treatment on the inner circumferential surface of the track bushing material, thereby minimizing the softening section of the track bush core and extending the wear life through the expansion of the outer hardened layer area. It is an object of the present invention to provide a new type of internal high frequency heat treatment based track bush manufacturing method and internal high frequency heat treatment device for manufacturing track bushes that can minimize side wear while maintaining the side hardness of the track bush continuously.

According to a feature of the present invention for achieving the above object, the present invention is characterized in that the carbon steel is made of a material in which 0.5 to 0.7 wt% of carbon, 0.3 to 0.6 wt% of chromium, and 0.3 to 0.7 wt% of molybdenum are added. Provides a track bush with improved surface hardness.

According to another feature of the present invention for achieving the above object, the present invention is a material cutting step of cutting the tube-shaped raw material to form the track bushing material (2); A front curing heat treatment step of heating the track bushing material 2 so as to transfer heat to the outer circumferential surface, the inner circumferential surface and the inside of the track bushing material 2, and then cooling the entire track bushing material 2; A first tempering step of performing a tempering heat treatment on the front-cured heat-treated track bush material (2); Inner diameter high frequency heat treatment step of induction heating and cooling the inner circumferential surface of the first tempered track bushing material 2; A second tempering step of performing a tempering heat treatment on the track bushing material 2, which has been subjected to internal high-frequency heat treatment; It provides a method for manufacturing a track bush with an internal diameter high-frequency heat treatment, characterized in that it comprises; a post-processing step of generating the track bush 3 through a post-processing process for the second tempered track bushing material 2.

In the method for manufacturing an inner diameter high frequency heat treatment-based track bush according to the present invention, the inner frequency high frequency heat treatment step has a structure in which the high frequency induction heating portion and the cooling portion gradually move from the inner one end of the track bushing material 2 to the other end. However, it is possible to ensure that high-frequency induction heating and cooling for the same site are sequentially performed with a minimum time interval set in synchronization with each other.

In the inner diameter high frequency heat treatment based track bush manufacturing method according to the present invention, the inner high frequency heat treatment step may allow the cooling treatment on the outer peripheral surface of the track bushing material 2 to be simultaneously performed.

According to another feature of the present invention for achieving the above object, the present invention is installed at a set point high-frequency induction heater body 100 to induce the generation of high-frequency; A cooling water supply unit body 200 installed at a set point to supply cooling water at a set pressure; A material fixing jig 300 in which the tube-shaped track bushing material 2 is erected and fixed vertically; It is connected to the high frequency induction heater main body 100 and is disposed vertically inside the track bushing material 2 fixed to the material fixing jig 300, and is top from the bottom of the inner circumferential surface of the track bushing material 2 Heating coil 400 to perform high-frequency induction heating while moving upward; The cooling water supply unit is connected to the main body 200, and is connected to the lower end of the heating coil 400 to move upwardly integrally with the heating coil 400, and the inner diameter injection nozzle 510 along the outer circumference. An inner diameter cooling jacket 500 formed and spraying cooling water to the inner circumferential surface of the track bushing material 2; It is connected to the main body of the cooling water supply 200, and is disposed surrounding the track bushing material 2 on the outside of the track bushing material 2, and the outer diameter side spray nozzle 610 is formed along the inner circumferential surface to track the track. Provided is an inner diameter high frequency heat treatment apparatus for manufacturing a track bush, characterized in that it comprises a configuration including; an outer diameter cooling jacket (600) that sprays cooling water to the outer circumferential surface of the bush material (2).

In the inner diameter high frequency heat treatment apparatus for manufacturing a track bush according to the present invention, the material fixing jig 300 is formed with a circular mounting groove 311 in which the track bushing material 2 is fitted and fixed on an upper surface. A plate-shaped horizontal fixing plate 310 in which a plurality of coolant discharge holes 312 arranged in a set pattern in the groove 311 penetrates the lower surface; It may be formed in a configuration including a; vertically extending from the lower surface of the horizontal fixing plate 310 in a downward direction and inducing rotation of the horizontal fixing plate 310.

According to the track bush with improved surface hardness according to the present invention, the occurrence of cracks is minimized by improving the surface hardness through increasing carbon content, reducing chromium content, and adding molybdenum. And according to the track bore manufacturing method based on the inner bore high frequency heat treatment according to the present invention and the bore bore heat treatment device for track boke production, the track bushing material is subjected to a front hardening heat treatment, and then a high frequency heat treatment is performed on the inner circumferential surface of the track bush material. By minimizing the softening section of the bush core, the wear life is extended through the expansion of the outer hardened layer area, and the side hardness of the track bush is continuously maintained to minimize side wear.

1 is a view for showing the assembly and wear parts of the track bush applied to heavy equipment;
Figure 2 is a block diagram of a method for manufacturing an inner diameter high frequency heat treatment based track bush according to the present invention;
3 is a block diagram of a method for manufacturing a track bushing based on an internal diameter high frequency heat treatment according to an embodiment of the present invention;
4 is a system configuration for implementing a track bush manufacturing method based on an internal diameter high frequency heat treatment according to an embodiment of the present invention;
5 is a view for giving a track bush manufactured by a method for manufacturing an inner diameter high frequency heat treatment based track bush according to an embodiment of the present invention;
6 is an enlarged view of a portion “B” of FIG. 5;
7 is an exploded view of a main part of an inner diameter high frequency heat treatment apparatus for manufacturing a track bush according to an embodiment of the present invention;
Figure 8 is a main part of the inner diameter high-frequency heat treatment apparatus for manufacturing a track bush according to an embodiment of the present invention;
9 is a view for showing a horizontal fixing plate of the material fixing jig according to an embodiment of the present invention;
10 is a view for showing a heating coil and an inner diameter cooling jacket according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings FIGS. 1 to 10. On the other hand, in the drawings and detailed description, workers in this field can easily know from general track bushing, front hardening heat treatment, tempering, internal high frequency heat treatment, high frequency induction heater, high frequency induction heating, cooling water supply, spray nozzle, etc. Figures and references to construction and operation are simplified or omitted. In particular, in the illustration and detailed description of the drawings, a detailed description and illustration of specific technical configurations and operations of elements not directly related to the technical features of the present invention are omitted, and only the technical configurations related to the present invention are briefly illustrated or described. Did.

The track bush according to the present invention is made of a material in which 0.5 to 0.7 wt% of carbon, 0.3 to 0.6 wt% of chromium, and 0.3 to 0.7 wt% of molybdenum are added to carbon steel. In particular, the track bush according to the embodiment of the present invention is made of low carbon steel as a main material, and in addition to low carbon steel, carbon (C) 0.5 to 0.7 wt%, silicon (Si) 0.1 to 0.4 wt%, manganese (Mn) 0.6 to 0.8 wt%, phosphorus (P) 0.03 wt% or less, sulfur (S) 0.008 wt% or less, copper (Cu) 0.06 wt% or less, chromium (Cr) 0.5 to 0.6 wt%, molybdenum (Mo) 0.3 to 0.7 wt%, It is made of a material to which aluminum (Al) 0.01 to 0.06 wt% is added. This is a carbon content is increased compared to the material of the conventional track bush, while the chromium content is reduced, molybdenum not included in the material of the conventional track bush is added, through which the surface hardness of the track bush 3 Improved to minimize cracking. This makes it possible to prevent premature wear of the outer surface of the track bush 3.

The track bush manufacturing method based on the inner diameter high frequency heat treatment according to the present invention is performed through a material cutting step, a front hardening heat treatment step, a first tempering step, an inner diameter high frequency heat treatment step, a second tempering step, and a post processing step as shown in FIG. 2. do.

The material cutting step is a step of cutting the tube-shaped raw material to form the track bushing material 2. Here, the raw material is made of the aforementioned material. That is, low carbon steel is used as the main material, and in addition to low carbon steel, carbon (C) 0.5 to 0.7 wt%, silicon (Si) 0.1 to 0.4 wt%, manganese (Mn) 0.6 to 0.8 wt%, phosphorus (P) 0.03 wt% or less , Sulfur (S) 0.008 wt% or less, Copper (Cu) 0.06 wt% or less, Chromium (Cr) 0.5 to 0.6 wt%, Molybdenum (Mo) 0.3 to 0.7 wt%, Aluminum (Al) 0.01 to 0.06 wt% added It is made of material.

Here, the method for manufacturing an inner diameter high frequency heat treatment-based track bush according to an embodiment of the present invention performs a roughing step after a material cutting step, as shown in FIG. 3, and then performs a front hardening heat treatment step.

The front hardening heat treatment step is a step of heating the track bushing material 2 so as to transfer heat to the outer circumferential surface, the inner circumferential surface and the inside (deep) of the track bushing material 2, and then cooling the entire track bushing material 2. This is because it is possible to manufacture the track bush 3 of the desired quality only when the front hardening heat treatment step is performed before the inner high frequency heat treatment step. Here, the front hardening heat treatment step according to an embodiment of the present invention is such that the track bushing material 2 is supplied to the material transport conveyor 9 through the step feeder 4, as shown in FIG. 4, and the material transport conveyor 9 Through this, the track bushing material 2 is continuously and uniformly supplied to the electric furnace 5. And while the track bushing material 2 passes through the electric furnace 5, it is rapidly heated not only to the outer circumferential surface and inner circumferential surface of the track bushing material 2, but also to the inside (deep), and then the entire part is submerged in the cooling water tank 6, Accordingly, the entire track bushing material 2 is cured.

The first tempering step is a step in which the tempering heat treatment is performed while the track bushing material 2 which has been heat-hardened is passed through the tempering heat treatment furnace 7 as shown in FIG. 4. Through this, residual stress of the track bushing material 2 is removed.

Here, the method for manufacturing an inner diameter high frequency heat treatment-based track bush according to an embodiment of the present invention performs a first magnetic particle detection step after the first tempering step as shown in FIG. 3, and then performs an inner diameter high frequency heat treatment step.

The internal high-frequency heat treatment step is a step of high-frequency induction heating and cooling the inner peripheral surface of the first tempered track bushing material 2. Herein, the internal-diameter high-frequency heat treatment step according to the embodiment of the present invention allows the track bushing material 2 to be supplied to the material transfer conveyor 9 through the step feeder 4 as shown in FIG. 4, and the material transfer conveyor 9 Through this, the track bushing material 2 is continuously and uniformly supplied to the atmospheric region of the internal high-frequency heat treatment apparatus 1.

In addition, the internal high-frequency heat treatment step according to an embodiment of the present invention is performed with a structure in which the high-frequency induction heating portion and the cooling portion gradually move from one end portion of the track bushing material 2 to the other end portion, and the high-frequency induction for the same portion The heating and cooling are synchronized to each other and performed sequentially with a minimum time interval set.

In addition, the internal high-frequency heat treatment step according to an embodiment of the present invention allows the cooling treatment on the outer peripheral surface of the track bushing material 2 to be performed simultaneously. Heat generated during high-frequency induction heating to the inner circumferential surface of the track bushing material (2) is transferred to the entire track bushing material (2), and the surface hardness of the raised outer circumferential surface and side surface may be loosened by the front hardening heat treatment. In order to do this, the cooling treatment for the outer peripheral surface of the track bushing material 2 is performed simultaneously.

Here, the internal high-frequency heat treatment step rapidly cools the track bushing material 2 by spraying coolant with the track bushing material 2.

The internal high frequency heat treatment step according to an embodiment of the present invention is performed through the internal high frequency heat treatment device 1 for manufacturing a track bush according to an embodiment of the present invention to be described later.

The second tempering step is a step in which the tempering heat treatment is performed while the track bushing material 2 heat-treated with the inner diameter high-frequency passes through the tempering heat treatment furnace 7 ′ as shown in FIG. 4. Through this, residual stress of the track bushing material 2 is removed.

Here, the method for manufacturing an inner diameter high frequency heat treatment-based track bush according to an embodiment of the present invention performs a second magnetic particle detection step after the second tempering step as shown in FIG. 3, and then performs a post-processing step.

The post-processing step is a step of post-processing the second tempered track bushing material 2 with a post-processing device 8 to generate a track bush 3. In the post-processing step, the outer peripheral surface of the track bushing material 2 may be polished, or the inner peripheral surface/outer surface/side surface of the track bushing material 2 may be processed.

The track bush 3 manufactured through the inner diameter high frequency heat treatment based track bush manufacturing method according to the embodiment of the present invention configured as described above has an outer hardened layer region as shown in FIGS. 5 and 6 and a deep softening section. Minimized.

The inner diameter high frequency heat treatment apparatus 1 for manufacturing a track bush according to an embodiment of the present invention is a high frequency induction heater body 100, a cooling water supply apparatus body 200, a material fixing jig 300, as shown in FIGS. 7 to 10, It consists of a configuration including a heating coil 400, an inner diameter cooling jacket 500, and an outer diameter cooling jacket 600.

The high frequency induction heater main body 100 is installed at a set point to induce generation of high frequency. The heating coil 400 is connected to a CT box (Cable Termination Box) 110 provided in the high-frequency induction heater main body through a fastening nut.

The cooling water supply main body 200 is installed at a set point to supply cooling water at a set pressure. The connection pipes 210 and 220 such as hoses connected to the inner diameter cooling jacket 500 and the outer diameter cooling jacket 600 are connected to the cooling water supply device main body 200.

The material fixing jig 300 is a jig in which the tube-shaped track bushing material 2 is erected and fixed vertically. Here, the material fixing jig 300 according to the exemplary embodiment of the present invention is configured to include a horizontal fixing plate 310 and a vertical swivel 320.

The horizontal fixing plate 310 is formed in a plate shape, and a circular mounting groove 311 in which the track bushing material 2 is fitted and fixed is formed on the upper surface as shown in FIG. 9. The mounting groove 311 has a plurality of cooling water discharge holes 312 arranged in a set pattern through the lower surface. In particular, the horizontal fixing plate 310 according to the embodiment of the present invention allows one cooling water discharge hole 312 to be formed at the center, and a plurality of cooling water discharge holes 312 in a circle along the center of the cooling water discharge hole 312 ). Here, the cooling water discharge hole 312 is formed to be inclined to the outside corresponding to the rotating horizontal fixing plate 310 so that the cooling water can be discharged smoothly.

The vertical swivel 320 is formed to extend downward from the lower surface of the horizontal fixing plate 310, and is integrally coupled with the horizontal fixing plate 310. In particular, the vertical swivel 320 according to an embodiment of the present invention is connected to the driving motor 800 to rotate, through which the rotation of the horizontal fixing plate 310 is induced. As the horizontal fixing plate 310 rotates, high-frequency induction heating and cooling of the track bushing material 2 fixed to the horizontal fixing plate 310 can be performed uniformly over the entire region, thereby forming a uniform high-frequency pattern. There will be.

The heating coil 400 is connected to the main body 100 of the high frequency induction heater, and is disposed vertically inside the track bushing material 2 fixed to the material fixing jig 300, and the inner peripheral surface of the track bushing material 2 High-frequency induction heating is performed while moving upward from the bottom to the top.

The inner diameter cooling jacket 500 is connected to the main body 200 of the cooling water supply unit to receive cooling water, and is disposed at the lower end of the heating coil 400 to move upwards integrally with the heating coil 400. The inner diameter side injection nozzle 510 is formed along the circumference of the outer circumferential surface of the inner diameter cooling jacket 500 to spray cooling water to the inner circumferential surface of the track bushing material 2 to rapidly cool the inner circumferential surface of the track bushing material 2. Here, the inner diameter injection nozzle 510 according to the embodiment of the present bruise is formed to be inclined downward toward the center axis direction of the track bushing material 2.

Here, the heating coil 400 and the inner diameter cooling jacket 500 are fixedly arranged on the lower outer circumferential surface and the lower end of the fixing tube 700. Accordingly, high-frequency induction heating and cooling of the same parts of the track bushing material 2 are sequentially performed in synchronization with each other with a minimum time interval set.

The outer diameter cooling jacket 600 is connected to the cooling water supply unit main body 200, and is disposed while surrounding the track bushing material 2 on the outside of the track bushing material 2, and the outer diameter side injection nozzle 610 along the inner circumferential surface. This is formed to spray the coolant to the outer peripheral surface of the track bushing material (2). Here, the outer diameter cooling jacket 600 continuously sprays cooling water from the inner diameter high frequency heat treatment step to the end point. Here, the outer diameter-side injection nozzle 610 according to the embodiment of the present bruise is formed to be inclined downward toward the center axis direction of the track bushing material 2.

The track bore manufacturing method and the bore bore heat treatment apparatus for track boke manufacturing according to the embodiment of the present invention constituted as described above and the track boke material (2) are subjected to front hardening heat treatment for the track bush material (2) and then the track bush material (2). Since high-frequency heat treatment is performed on the inner circumferential surface, the softening section of the core of the track bush 3 is minimized so that the wear life can be extended through the expansion of the outer hardened layer area, and the lateral hardness of the track bush 3 is continuously maintained. Make sure that side wear is minimized.

As described above, the method for manufacturing an inner diameter high frequency heat treatment based track bush and the inner diameter high frequency heat treatment apparatus for track bush production according to the embodiments of the present invention are shown in accordance with the above description and drawings, but this is for example only, and the present invention Those skilled in the art will appreciate that various changes and modifications are possible without departing from the technical spirit.

1: Inner diameter high frequency heat treatment device for track bush manufacturing
2: Track bush material
3: track bush
4, 4': Step feeder
5: electric furnace
6: Cooling water tank
7, 7': Tempering heat treatment furnace
8: Post-processing processing device
9: Material transfer conveyor
100: high-frequency induction heater body
110: CT box
120: connecting cable
200: cooling water supply body
210, 220: connector
300: material fixing jig
310: horizontal fixed plate
311: mounting groove
312: cooling water discharge hole
320: vertical swivel
400: heating coil
500: inner diameter cooling jacket
510: inner diameter injection nozzle
600: outer diameter cooling jacket
610: outer diameter injection nozzle
700: fixed tube
800: drive motor

Claims (5)

A track bush with improved surface hardness, characterized by being made of a material in which 0.5 to 0.7 wt% of carbon, 0.3 to 0.6 wt% of chromium, and 0.3 to 0.7 wt% of molybdenum are added to carbon steel. A material cutting step of cutting the tubular raw material to form a track bushing material 2;
A front hardening heat treatment step of heating the track bushing material 2 so as to transfer heat to the outer circumferential surface, the inner circumferential surface and the inside of the track bushing material 2, and then cooling the entire track bushing material 2;
A first tempering step of performing a tempering heat treatment on the front-cured heat-treated track bush material (2);
An inner diameter high frequency heat treatment step of induction heating and cooling the inner circumferential surface of the first tempered track bushing material 2;
A second tempering step of performing a tempering heat treatment on the track bushing material 2, which has been subjected to internal high-frequency heat treatment;
And a post-processing step of generating the track bush (3) through a post-processing process for the second tempered track bushing material (2). According to claim 2,
The inner diameter high frequency heat treatment step,
High-frequency induction heating and cooling regions are performed in a structure that gradually moves from one end of the track bushing material (2) to the other, while the high-frequency induction heating and cooling for the same region are synchronized with each other to establish a set minimum time interval. While having it performed sequentially,
Method for manufacturing an inner diameter high frequency heat treatment based track bush, characterized in that cooling treatment for the outer peripheral surface of the track bushing material (2) is performed simultaneously. A high frequency induction heater main body 100 installed at a set point to induce generation of high frequencies;
A cooling water supply unit body 200 installed at a set point to supply cooling water at a set pressure;
A material fixing jig 300 in which the tubular track bushing material 2 is erected and fixed vertically;
It is connected to the high frequency induction heater main body 100 and is disposed vertically inside the track bushing material 2 fixed to the material fixing jig 300, and is top from the bottom of the inner circumferential surface of the track bushing material 2 Heating coil 400 to perform high-frequency induction heating while moving upward;
The cooling water supply unit is connected to the main body 200, and is connected to the lower end of the heating coil 400 to move upwardly integrally with the heating coil 400, and the inner diameter injection nozzle 510 along the outer circumference. An inner diameter cooling jacket 500 formed and spraying cooling water to the inner peripheral surface of the track bushing material 2;
It is connected to the main body of the cooling water supply 200, and is disposed surrounding the track bushing material 2 on the outside of the track bushing material 2, and the outer diameter side spray nozzle 610 is formed along the inner circumferential surface to track the track. Track bush manufacturing inner diameter high frequency heat treatment apparatus, characterized in that consisting of a configuration comprising; outer diameter cooling jacket 600 to spray the cooling water to the outer peripheral surface of the material (2). The method of claim 4,
The material fixing jig 300,
A circular mounting groove 311 in which the track bushing material 2 is fitted and fixed is formed on the upper surface, and a plurality of cooling water discharge holes 312 arranged in a setting pattern in the mounting groove 311 penetrates the lower surface. Plate-shaped horizontal fixing plate 310 formed by;
It is formed in a downward direction from the lower surface of the horizontal fixing plate 310, a vertical rotating table 320 for guiding the rotation of the horizontal fixing plate 310; inner diameter high frequency heat treatment for manufacturing a track bush, characterized in that it comprises a configuration comprising a Device.

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