JP5901013B2 - Non-oxidation induction heat treatment equipment - Google Patents

Description

The present invention relates to a non-oxidation high-frequency heat treatment apparatus for heat-treating predetermined portions of various shapes of workpieces in a non-oxidation state by high-frequency induction heating or the like.

  Conventionally, for example, when brazing the end faces of a pair of workpieces, a silver solder is set between the joining end faces, and a high-frequency current is supplied from a high-frequency power source to a heating coil arranged around the joining part. Induction heating is used to melt and braze silver solder. In such an apparatus, when high quality is required for the brazed portion, a work is placed in a case such as a chamber, and an inert gas such as nitrogen gas is introduced into the case from a gas supply port provided in the case. Is supplied (injected) to make the inside of the case non-oxidized and brazed. An apparatus that performs high-frequency heat treatment in a non-oxidized state is disclosed in Patent Document 1, for example.

JP 2001-59116 A

  However, in such a heat treatment apparatus, the volume of the case itself is set to be relatively large, and a structure in which an inert gas is supplied from the gas supply port provided at a predetermined position of the case toward the entire area of the case. Therefore, the amount of inert gas supplied into the case itself increases, and the time until the entire region in the case becomes non-oxidized, that is, the time for gas replacement becomes longer. Inferior. In addition, since it is difficult to uniformly supply (inject) the inert gas to substantially the entire heat treatment portion of the work, it is difficult to maintain the non-oxidized state of the heat treatment portion of the work with high accuracy and Since it is difficult to detect the heating temperature with high accuracy, it is difficult to obtain a desired heating temperature. From these, it is difficult to obtain a high-quality heat treatment state on the workpiece.

The present invention has been made in view of such circumstances, and its purpose is to improve the efficiency of heat treatment work by reducing the amount of inert gas used and making the periphery of the heat treated portion non-oxidized in a short time. An object of the present invention is to provide an oxidation-free high-frequency heat treatment apparatus that can simultaneously obtain a high-quality heat treatment state.

In order to achieve such an object, the invention according to claim 1 of the present invention is not attached to a cylindrical body having a shape substantially corresponding to the outer shape of the heat-treated portion of the workpiece and one open end of the cylindrical body. A lid having an active gas supply port; a work support that is detachably attached to the other opening end of the cylinder; and a position corresponding to a heat treatment portion of the work on the outer periphery of the cylinder. A heating coil provided; a transistor inverter capable of supplying high-frequency current to the heating coil; and a control device that controls the transistor inverter. The cylindrical body includes an outer cylindrical body and an inner cylindrical body. Gas flow paths are provided between the bodies, and a plurality of rows of gas injection holes that can inject inert gas toward the heat treatment portion are provided in the circumferential direction at positions facing the heat treatment portion of the workpiece of the inner cylindrical body. The lid body has an outer wall and an inner wall and has a cylindrical direction. A gas flow path that expands in a conical shape and can be tightly connected to the gas flow path of the cylindrical body is provided, and the work support base or the lid body has oxygen in the inner cylindrical body at the time of gas replacement. The inert gas flows from a gas hose connected to the supply port of the lid body to a gas flow path of the lid body having a size corresponding to the inner diameter of the gas hose. And is injected into the inner cylinder through a gas flow path of the cylinder .

According to a second aspect of the present invention, a plurality of the discharge holes penetrates in the axial direction of the cylindrical body between the cylindrical positioning projections provided on the work support base and the workpiece positioning projections in the circumferential direction. It is provided . According to a third aspect of the present invention, the cylindrical body is formed of a material that allows the inside to be visually recognized, and an infrared radiation thermometer capable of detecting the temperature of the heat treatment portion is disposed outside the cylindrical body. It is characterized by. Furthermore, the invention described in claim 4 is characterized in that the heating coil is integrated with the cylindrical body and is disposed so as to be movable back and forth with respect to the work support base . The invention according to claim 5 is characterized in that the portion of the inner cylinder where the gas injection hole is provided is formed of a different material from the other portions .

According to the invention described in claim 1 or 2 of the present invention, the cylinder has the outer cylinder and the inner cylinder, the gas flow path is provided between the two cylinders, and the inert gas is provided in the inner cylinder. Since a plurality of gas injection holes that can inject gas are provided, an inert gas is injected into the inner cylinder from the relatively narrow gas flow path between the outer cylinder and the inner cylinder to the heat treatment portion. The inside of the cylinder can be replaced with gas, and the amount of inert gas used is reduced, and the periphery of the heat treatment part of the workpiece is made non-oxidized in a short time, improving the efficiency of heat treatment work and obtaining high-quality heat treatment simultaneously and easily. be able to.

In addition, since the work support base or lid is provided with a discharge hole through which oxygen in the inner cylinder can be discharged to the outside of the cylinder when the gas in the inner cylinder is replaced, The oxygen (air) can be quickly discharged from the discharge hole, and the gas replacement in the inner cylinder can be performed in a shorter time and more reliably .

According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, the cylindrical body is formed of a material that allows the inside to be visually recognized, and a heat treatment portion is formed outside the cylindrical body. Since an infrared radiation thermometer capable of detecting the temperature of the tube is provided, an inexpensive, transparent or translucent cylinder such as a quartz tube can be used as the cylinder, and the temperature of the heat treatment portion can be increased by using this cylinder. Can be detected from the outside of the cylinder, and the heat treatment quality can be further enhanced, for example, the desired heat treatment temperature can be reliably obtained .

Furthermore, according to the invention described in claim 4, in addition to the effects of the invention described in claims 1 to 3 , the heating coil is integrated with the cylindrical body so as to be movable forward and backward with respect to the work support base. Therefore, for example, the positional relationship between the cylinder and the heating coil corresponding to the shape of the workpiece can be maintained as desired, the heating state of the heat treatment portion of the workpiece can be stabilized, and the cylinder and the heating coil can be treated for heat treatment. It can be used as a tool and can be easily applied to workpieces of various shapes .

According to the invention described in claim 5, in addition to the effects of the invention described in claims 1 to 4, the portion where the gas injection hole of the inner cylinder is provided is formed of a different material from other portions. Therefore, for example, the portion where the gas injection hole is provided can be formed of a material such as ceramic, and the other portion can be formed of a material such as a quartz tube, so that a desired gas injection hole can be easily formed and the heat treatment portion of the workpiece can be heated. It is possible to accurately respond to heat treatment of various workpieces, such as using materials that correspond to temperature .

Schematic configuration diagram of non-oxidation induction heat treatment apparatus according to the present invention Cross-sectional view of the cylinder Longitudinal sectional view of the main part of the cylinder Vertical section of the lid 1 is a longitudinal sectional view of part A in FIG. Process diagram of heat treatment method using the same device Longitudinal sectional view of the main part showing a modification of the cylinder

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
1-6 has shown one Embodiment of the non-oxidation induction heat processing apparatus concerning this invention. As shown in FIG. 1, a non-oxidation induction heat treatment apparatus 1 (hereinafter referred to as a heat treatment apparatus 1) includes a cylindrical tubular body 2 in which a pair of workpieces Wa and Wb to be brazed is accommodated and set, and the tubular body. The lid 3 that closes the upper surface opening 2a in FIG. 1 that is one of the opening ends of the two and a predetermined position in the height (longitudinal) direction of the cylindrical body 2 has a predetermined interval with respect to the outer peripheral surface. And a heat treatment jig 5 including a heating coil 4 and the like which are integrally disposed.

  This heat treatment jig 5 is moved up and down so that the lower surface opening 2b of FIG. 1 which is the other opening end of the cylindrical body 2 is set on or removed from the work support 6. It is arranged to be possible. An infrared radiation thermometer 7 is disposed at a predetermined position outside the outer peripheral surface of the cylindrical body 2 of the heat treatment jig 5 toward the inside of the cylindrical body 2. A gas supply unit 9 for supplying an inert gas such as nitrogen gas or argon gas to the inside of the cylindrical body 2 is connected to a hose connector 8 provided on an upper surface portion 3a, which will be described later, of the lid 3 via a gas hose 10. The heating coil 4 is connected to a transistor inverter 11 as a high frequency power source.

  Further, a jig driving unit 12 is connected to the cylindrical body 2, and the jig driving unit 12 operates to move the heat treatment jig 5 including the cylindrical body 2, the lid body 3, and the heating coil 4 to an arrow. It can move up and down like a. And these gas supply part 9, transistor inverter 11, and jig drive part 12 are connected to control device 13 which has CPU, ROM, RAM, a timer, etc. which are not illustrated, and by the control signal of this control device 13, The operation is as described later. The infrared radiation thermometer 7 is connected to the control device 13.

  As shown in FIGS. 2 and 3, the cylindrical body 2 has a cylindrical shape corresponding to the outer peripheral surface shape of the cylindrical workpieces Wa and Wb, and is formed of a transparent or translucent quartz tube whose inside is visible. The outer cylindrical body 2A and the inner cylindrical body 2B are provided, and a gas channel 15 having a predetermined width is formed between the two cylindrical bodies 2A and 2B. Further, a gas injection portion 16 formed in an annular shape with a predetermined width is provided at a position corresponding to the heat treatment portion of the workpieces Wa and Wb at a predetermined position in the height direction of the inner cylinder 2B. 16, for example, a large number of circular gas injection holes 16a are formed in the direction of the central axis of the inner cylinder 2B.

  At this time, the gas injection holes 16a are set to have an inner diameter at which a predetermined injection pressure is obtained, and are formed in a plurality of rows in the circumferential direction, and the upper and lower gas injection holes 16a are in the staggered position or the same. As shown in FIG. 2 and FIG. 3, the gas in the gas flow path 15 is injected at a predetermined pressure toward the inside of the inner cylindrical body 2B. The lower ends of the outer cylinder 2A and the inner cylinder 2B are closed by a bottom plate 17 as shown in FIG.

The lid 3 is formed of a heat-resistant material such as a ceramic material or a gypsum board material, and as shown in FIGS. 1 and 4, a flat upper surface portion 3a composed of an outer wall and an inner wall, respectively, A slope portion 3b extending in a conical shape downward from the outer periphery of the portion 3a is formed, and a gas flow path 18 is formed in a conical shape from the flat portion 3a to the slope portion 3b. An annular fitting portion 3c having an outer diameter substantially the same as the inner diameter of the inner cylinder 2B of the cylinder 2 is integrally formed at the lower end of the inner wall of the slope portion 3b. By causing the fitting from above the upper opening of the inner cylinder 2B a fitting portion 3c, at the lid 3 with the upper opening 2a of the tubular body 2 is closed, the gas flow path of the cover 3 18 Is in close communication with the upper end of the gas flow path 15 of the cylindrical body 2. The lid 3 can be detached from the cylinder 2 by pulling upward with a predetermined tensile force.

  The work support base 6 is formed in a disk shape having a predetermined height with an appropriate material having heat resistance. As shown in FIGS. A plurality of cylindrical body positioning projections 19a and 19b are integrally formed in the circumferential direction or are integrally formed in an annular shape. In addition, a workpiece positioning projection 20 for positioning the workpiece Wa is integrally formed on the inner side of the positioning projection 19b of the workpiece support base 6 in the same form as the cylinder positioning projections 19a and 19b. A plurality of discharge holes 21 penetrating in the axial direction of the cylindrical body 2 which is the vertical direction are formed between the 19b and the workpiece positioning projection 20 at regular intervals in the circumferential direction, for example.

  The oxygen (air) inside the inner cylinder 2B when the inert gas is supplied into the cylinder 2 as will be described later from the discharge hole 21 to the outside of the cylinder 2 (downward in the figure) as indicated by an arrow C. It is supposed to be discharged. In FIG. 5, the discharge hole 21 is a through hole. However, as shown by a two-dot chain line a, for example, a check valve 22 is provided in the discharge hole 21 or at the opening of the discharge hole 21 to It may be possible to discharge oxygen only in the direction. In FIG. 5, the discharge of oxygen in the cylinder 2 is discharged to the outside from the discharge hole 21 provided in the work support 6. For example, the discharge hole 21 is provided at a predetermined position of the lid 3 to provide oxygen in the cylinder 2. May be discharged upward. This case can be dealt with by arranging a pipe through which a discharge hole can be formed in the gas flow path 18 of the lid 3.

  The transistor inverter 11 has an inverter circuit composed of, for example, a full bridge circuit using a semiconductor switching element, and supplies a high-frequency current having a predetermined frequency to the heating coil 4 via an output transformer or the like. . At this time, the frequency of the output current of the transistor inverter is set in advance or can be adjusted by the control of the control device 13 according to the form of the workpieces Wa and Wb. The gas supply unit 9 has a gas cylinder of an inert gas, an electromagnetic valve connected to the supply port, and the like. The inert gas is supplied into 2 or the gas supply is stopped.

  Furthermore, the heating coil 4 is formed in a substantially cylindrical shape by, for example, winding a copper round pipe a predetermined number of times, and an outer cylinder 2A is interposed outside the gas injection part 16 of the inner cylinder 2B. The outer cylinder 2A is integrally connected by a connecting member (not shown) having a predetermined distance in the state. Note that the shape of the heating coil 4 is not limited to a wound shape, and may be a horseshoe shape, and an integrated structure with the outer cylindrical body 2A is not limited to a connecting structure using a connecting member, but an outer peripheral surface of the outer cylindrical body 2A. Alternatively, the structure may be directly fixed with an insulating adhesive or the like. The both ends of the heating coil 4 are connected to the output terminal of the transistor inverter 11. Further, in the copper pipe of the heating coil 4, cooling water is circulated and supplied from a cooling water supply device (not shown) attached to the transistor inverter 11 and the control device 13, and the heating coil 4 itself at the time of induction heating. Heat generation is suppressed, and a decrease in heating efficiency is suppressed.

  Next, an example of the heat treatment method by the heat treatment apparatus 1 configured as described above will be described based on the process diagram of FIG. First, the jig driving unit 12 is operated by the control device 13 to move the heat treatment jig 5 upward, and the lower end opening 2b of the cylindrical body 2 is retracted upward from the workpiece support base 6 by a predetermined distance. In this state, with a pair of upper and lower cylindrical dissimilar materials (or the same material), at least one of which is made of metal, the workpieces Wa and Wb are set in a state where a silver solder is set between the end surfaces serving as brazing portions. Set (K01) in the workpiece positioning projection 20 of the support base 6.

  When the workpieces Wa and Wb are set, the jig driving unit 12 is operated by the control device 13 to lower the heat treatment jig 5 (K02), and the outer peripheral portion of the lower end of the cylinder 2 is positioned on the cylinder positioning protrusion 19a of the workpiece support base 6. , 19b. As a result, as shown in FIG. 1, the gas injection part 16 of the inner cylinder 2 </ b> B is located at a predetermined interval on the outer peripheral side of the brazed portion of the pair of workpieces Wa and Wb, and in this state, The control device 13 operates the gas supply unit 9 to supply an inert gas to the heat treatment jig 5 (K03). The gas supplied from the gas supply unit 9 flows through the gas hose 10, the hose connector 8 of the lid 3, the gas flow path 18, and the gas flow path 15 of the cylinder 2, and the gas injection part 16 of the inner cylinder 2 </ b> B. The gas is injected from the gas injection hole 16a into the inner cylinder 2B. At this time, since the gas injection holes 16a are formed in a plurality of rows in the circumferential direction on the outer peripheral surface of the inner cylindrical body 2B, the inert gas is brazed between the gas injection holes 16a and the workpieces Wa and Wb. Injected in a uniform state toward

  Thus, the inert gas injected into the inner cylinder 2B causes oxygen in the inner cylinder 2B to be discharged from the discharge hole 21 to the outside of the cylinder 2, and the inner cylinder 2B is filled with the inert gas. It becomes a non-oxidized state. Then, at the time of transition to the non-oxidation state, that is, at the time of gas replacement in the inner cylinder 2B, the inert gas passes through the gas flow paths 18 and 15 having a size substantially corresponding to the inner diameter of the gas hose 10. Since the gas is injected from the gas injection holes 16a of the body 2B, an inert gas having a predetermined pressure can be effectively injected into the inner cylinder 2B, and at the same time the time for gas replacement in the inner cylinder 2B is shortened. The use amount of the inert gas itself can be reduced.

  When the inert gas is supplied for a predetermined time, the control device 13 operates the transistor inverter 11 (K04) while stopping the supply of the gas or continuously supplying the inert gas (K04). Supply. By supplying the high-frequency current to the heating coil 4, an eddy current is induced in the brazed part of the workpieces Wa and Wb by the magnetic flux generated from the heating coil 4, and the part is induction-heated. At this time, by setting the frequency and output of the high-frequency current supplied to the heating coil 4 in advance according to the material and form of the workpieces Wa and Wb, the brazed portion is rapidly heated to a predetermined temperature, and this heating is performed. As a result, the silver solder is melted and the pair of workpieces Wa and Wb are brazed. When the brazed portions of the workpieces Wa and Wb are induction-heated, the temperature of the brazed portion is detected by the infrared radiation thermometer 7 and input to the control device 13. The control device 13 compares the input detected temperature with a reference temperature set in advance according to the form of the workpieces Wa and Wb, etc., and when the detected temperature reaches the reference temperature, the control device 13 operates the transistor inverter 11. Stop.

  Then, the heat treatment jig 5 is raised by the control device 13 (K05), and then the brazed workpieces Wa and Wb are taken out from the workpiece support base 6 (K06). As a result, the brazing operation of the pair of workpieces Wa and Wb is completed, and the gas supply time can be shortened in this process as described above. Therefore, the time of the process K03 and the process K04 is used for a case such as a conventional chamber. Compared to the case, the work efficiency of the brazing work of the workpieces Wa and Wb can be improved. The above process is an example. For example, the workpieces Wa and Wb in the processes K01 and K06 may be automatically set and taken out by the robot. In this way, the brazing operation is completely automated. Can be achieved.

  Thus, in the heat treatment apparatus 1 of the above-described embodiment, the cylinder 2 constituting the heat treatment jig 5 has the outer cylinder 2A and the inner cylinder 2B, and the gas flow path 15 between the two cylinders 2A and 2B. And a plurality of gas injection holes 16a capable of injecting an inert gas are provided in the gas injection part 16 of the inner cylinder 2B, so that a relatively narrow gas between the outer cylinder 2A and the inner cylinder 2B is provided. From the flow path 15, the inert gas can be injected into the inner cylinder 2 </ b> B toward the brazed portion to replace the gas inside the inner cylinder 2 </ b> B. By making the periphery of the brazed portion non-oxidized in a short time, the efficiency of brazing work can be improved and a high quality brazed state can be obtained simultaneously and easily.

  In addition, since the cylindrical body 2 is formed of a quartz tube whose inside can be visually confirmed, and an infrared radiation thermometer 7 capable of detecting the temperature of the brazed portion is disposed outside the cylindrical body 2, the cylindrical body 2, an inexpensive, transparent or translucent quartz tube can be used, and the temperature of the induction heating portion can be detected from the outside of the cylinder 2 by using the cylinder 2, and the transistor inverter 11 is controlled based on the detected temperature. Thereby, brazing quality can be improved further, such as being able to obtain a desired heating temperature reliably.

  Further, since the heat treatment jig 5 in which the heating coil 4 is integrated with the cylindrical body 2 is disposed so as to be able to advance and retract with respect to the workpiece support base 6, for example, the cylindrical body 2 corresponding to the shapes of the workpieces Wa and Wb The positional relationship of the heating coil 4 can be maintained as desired, the heating state of the brazed portions of the workpieces Wa and Wb can be stabilized, and the cylindrical body 2 and the heating coil 4 can be used as a single heat treatment jig. Thus, it can be easily applied to workpieces Wa and Wb having various shapes.

  Furthermore, since the work support base 6 or the lid 3 is provided with a discharge hole 21 through which oxygen in the inner cylinder 2B can be discharged out of the cylinder 2 when the gas in the inner cylinder 2B is replaced, the inner cylinder Oxygen (air) in 2B can be quickly discharged from the discharge hole 21, and gas replacement in the inner cylinder 2B can be performed in a shorter time and more reliably. At that time, if the check valve 22 is provided in the discharge hole 21, the oxygen in the inner cylinder 2B can be discharged more reliably and in a short time.

  FIG. 7 shows a modification of the inner cylinder 2B. The feature of this modification is that the inner cylinder 2B is composed of a ceramic tube 23 as the gas injection unit 16 and upper and lower quartz tubes 24. That is, a gas injection hole 23a similar to the gas injection hole 16a is formed in the ceramic tube 23, and recesses 23b are provided at upper and lower ends thereof, and a sealing material such as an O-ring 25 or an adhesive is provided in the recess 23b. The upper and lower quartz tubes 24 are connected and fixed in close contact with each other to constitute the inner cylindrical body 2B.

  In the case of the inner cylindrical body 2B, the temperature of the brazed portion is detected by the infrared radiation temperature 7 through the upper and lower transparent or translucent quartz tubes 24. Also in this modified example, in addition to obtaining the same effects as those of the cylindrical body 2, the material of the gas injection part 16 can be formed of a material in which the gas injection holes 23a can be easily formed, and the shape, position, and the like are desired. The shape of the gas injection hole 23a can be easily formed at a desired position of the inner cylinder 2B, and a material corresponding to the heating temperature of the brazed portion of the work Wa, Wb can be used. The effect which can be obtained can be obtained. In the case of this modification, for example, the lower quartz tube 24 and the ceramic tube 23 may be integrally formed of a sexual material.

  In the above-described embodiment, the cylindrical body 2 is integrated with the heating coil 4 so that it can be used as the heat treatment jig 5. However, the present invention is not limited to this configuration. For example, the heating coil 4 is cylindrical. It can also be formed separately from the body 2. Moreover, in the said embodiment, although the cylindrical body 2 was made into the cylindrical shape corresponding to the cylindrical workpieces Wa and Wb, when the workpieces Wa and Wb are square, for example, the cylindrical body 2 and the heating coil 4 are square. The cylindrical body 2 having a shape corresponding to the outer shape of the workpiece may be used. Furthermore, the shape of the lid 3 and the configuration of the work support 6 in the embodiment are merely examples, and appropriate configurations can be employed without departing from the gist of the present invention.

  The present invention is not limited to a heat treatment apparatus that brazes a pair of workpieces by induction heating, but can also be used for all heat treatment apparatuses that use induction heating or the like, such as quenching or annealing of various workpieces.

  DESCRIPTION OF SYMBOLS 1 ... Non-oxidation induction heat processing apparatus, 2 ... Cylindrical body, 2A ... Outer cylindrical body, 2B ... Inner cylindrical body, 3 ... Cover body, 4 ... Heating coil, 5 ... -Heat treatment jig, 6 ... Work support, 7 ... Infrared radiation thermometer, 9 ... Gas supply unit, 11 ... Transistor inverter, 12 ... Jig drive unit, 13 ... Control device, 15 ... gas flow path, 16 ... gas injection part, 16a ... gas injection hole, 18 ... gas flow path, 19a, 19b ... cylinder positioning projection, 20 ... Work positioning protrusion, 21 ... discharge hole, 23 ... ceramic tube, 23a ... gas injection hole, 24 ... quartz tube, 25 ... O-ring, Wa, Wb ... work.

Claims (5)

A cylinder having a shape substantially corresponding to the outer shape of the heat treatment portion of the workpiece, a lid attached to one opening end of the cylinder and having an inert gas supply port, and the other opening end of the cylinder A workpiece support base that is detachably attached to the workpiece, a heating coil disposed at a position corresponding to a heat treatment portion of the workpiece at an outer peripheral portion of the cylindrical body, and a transistor inverter capable of supplying a high-frequency current to the heating coil; And a control device for controlling these,
The cylindrical body has an outer cylindrical body and an inner cylindrical body, a gas flow path is provided between both cylindrical bodies , and the cylindrical body faces the thermal processing portion at a position facing the thermal processing portion of the workpiece. Gas injection holes capable of injecting inert gas are provided in a plurality of rows in the circumferential direction,
The lid body has an outer wall and an inner wall, and is provided with a gas flow path that expands in a conical shape in the cylindrical body direction and can be tightly connected to the gas flow path of the cylindrical body,
The work support or the lid is provided with a discharge hole through which oxygen in the inner cylinder can be discharged out of the cylinder when replacing the gas in the inner cylinder.
The inert gas flows from the gas hose connected to the supply port of the lid body through the gas flow path of the lid body and the gas flow path of the cylindrical body corresponding to the inner diameter of the gas hose. A non-oxidation high-frequency heat treatment apparatus characterized by being injected into a cylinder . The said discharge hole is provided in the circumferential direction by penetrating in the axial direction of a cylinder between the cylinder positioning protrusion provided in the said workpiece | work support stand, and the workpiece positioning protrusion. The non-oxidation induction heat treatment apparatus according to 1. 2. The infrared ray thermometer capable of detecting the temperature of the heat treatment portion is disposed outside the cylindrical body, and the cylindrical body is formed of a material whose inside can be visually recognized. The non-oxidation induction heat treatment apparatus according to 2. The non-oxidation induction heat treatment apparatus according to any one of claims 1 to 3 , wherein the heating coil is integrated with the cylindrical body and disposed so as to be capable of moving forward and backward with respect to the work support . 5. The non-oxidation induction heat treatment apparatus according to claim 1, wherein a portion of the inner cylinder body in which the gas injection holes are provided is formed of a different material from the other portions .

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