JP2011214056A - Carburizing treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carburizing treatment apparatus with which the heat-loss during carburizing treatment to a work-piece can be restrained and the consumed quantity of energy can be reduced at lower than the conventional method.SOLUTION: A cylindrical directional regulating member 31, with which a shell-wall 11 of a treatment chamber 10 and an induction-heating coil 20, and the work-piece W in the carburizing treatment apparatus 1, are separated, and the carburizing atmospheric gas convected in the treatment chamber, made to flow from the work-piece W side to the shell-wall 11 side of the treatment chamber 10 and the induction-heating coil 20 side is regulated, is arranged. Thus, the heat-interchange among the carburizing atmospheric gas, the shell-wall 11 and the induction-heating coil 20, is restrained.

Description

  The present invention relates to a carburizing apparatus that performs a carburizing process on a steel workpiece.

  As one of the surface hardening treatment methods for steel parts used in automobiles and industrial machines, for example, a low-carbon steel workpiece is set inside the treatment chamber, and the surface layer of this workpiece is heated to a predetermined temperature by high-frequency induction heating. A high frequency carburizing method in which carburizing treatment is performed by supplying carburizing gas into the processing chamber after heating is employed (see, for example, Patent Document 1).

  In the high-frequency carburizing method, for example, as shown in FIG. 4, a processing chamber 110 that sets a work W inside, a water-cooled induction heating coil 120 that is installed inside the processing chamber 110 and heats the work W, A carburizing apparatus 101 including a gas flow path 150 for supplying a carburizing gas into the processing chamber 110 and an exhaust gas flow path 160 for discharging the exhaust gas in the processing chamber 110 is used.

  In the high-frequency carburizing method using the carburizing apparatus 101, first, the surface layer of the workpiece W set in the processing chamber 110 is induction-heated to a predetermined temperature by the induction heating coil 120. Thereafter, for example, a carburizing gas obtained by mixing the hydrocarbon gas supplied from the hydrocarbon gas cylinder 151 with the dilution gas supplied from the dilution gas cylinder 152 is fed into the processing chamber 110 via the gas flow path 150 to perform the processing. A carburizing atmosphere gas is generated in the chamber 110, and the carburizing atmosphere gas is brought into contact with the surface of the workpiece W at a high temperature. At this time, carbon generated by the carburizing reaction of hydrocarbons in the carburizing atmosphere gas on the surface of the workpiece W diffuses and penetrates from the surface of the workpiece W to the inside. Thereby, since the carbon content on the surface of the workpiece W is improved, the surface layer of the workpiece W is cured.

JP 2004-360057 A

  However, in the conventional carburizing apparatus 101, the carburizing atmosphere gas in the vicinity of the workpiece W is heated by the radiant heat of the heated workpiece W during the carburizing process of the workpiece W, so that the carburizing atmosphere is generated inside the processing chamber 110. Since gas convection (arrow C) and diffusion (arrow D) occur, heat exchange is promoted between the carburizing atmosphere gas and the shell wall 111 of the processing chamber 110 and the induction heating coil 120. For this reason, the carburizing apparatus 101 has a problem that heat loss during the carburizing process of the workpiece W is large, the amount of energy consumed for the carburizing process is increased, and the carburizing process cost is high.

  The present invention has been made in view of such problems, and can provide a carburizing apparatus that can suppress heat loss during the carburizing process of a workpiece and can reduce the cost of carburizing process. Objective.

  The carburizing apparatus of the present invention is a carburizing apparatus that performs a carburizing process on a steel workpiece, and is installed in the processing chamber in which the workpiece is set, and surrounds the workpiece. An induction heating coil for heating, a gas supply passage for supplying a carburizing gas into the processing chamber, an exhaust gas passage for exhausting a carburizing atmosphere gas in the processing chamber, a shell wall of the workpiece and the processing chamber, and an induction heating coil. A carburizing atmosphere gas that divides and convects the processing chamber is provided with a cylindrical direction regulating member that regulates the flow of the carburizing atmosphere gas from the workpiece side to the shell wall side and the induction heating coil side of the processing chamber.

  In the carburizing treatment apparatus of the present invention, the direction restriction member restricts the flow of the carburizing atmosphere gas convection in the processing chamber from the workpiece side to the shell wall side of the processing chamber and the induction heating coil side, and thereby the carburizing atmosphere gas. Exchange between the shell wall of the processing chamber and the induction heating coil can be suppressed, so that heat loss during the carburizing process of the workpiece can be suppressed.

  The carburizing apparatus of the present invention introduces a carburizing atmosphere gas that has passed through the inside of the direction regulating member, and returns the carburizing atmosphere gas to a space between the shell wall of the processing chamber and the direction regulating member at a predetermined flow rate. It is preferable that a reflux regulating member is provided. According to this carburizing apparatus, the carburizing atmosphere gas introduced from the inside of the direction regulating member can be refluxed at a predetermined flow rate to the space between the shell wall of the processing chamber and the direction regulating member by the reflux regulating member. it can. By setting the recirculation amount of the charcoal atmosphere gas to the space by the recirculation restriction member to an appropriate value according to characteristics such as the material and surface area of the workpiece, the temperature of the carburizing atmosphere gas in the processing chamber and / or The composition can be set to an appropriate value according to the characteristics of the workpiece. Therefore, according to this carburizing apparatus, the carburizing process of the workpiece can be performed uniformly and efficiently. Moreover, since the unreacted gas in the carburizing atmosphere gas refluxed to the space can be reused, the carburizing cost can be reduced.

  The carburizing apparatus according to the present invention preferably includes a residence time adjusting member that adjusts the residence time of the carburizing atmosphere gas inside the direction regulating member. According to this carburizing apparatus, by setting the residence time of the carburizing atmosphere gas in the direction regulating member appropriately according to the characteristics such as the material and surface area of the workpiece by the residence time adjusting member, Carburizing treatment of the workpiece can be performed more uniformly and efficiently.

  The dwell time adjusting member may be a damper capable of variably adjusting the flow rate of the carburizing atmosphere gas introduced from the inside of the direction regulating member to the inside of the reflux regulating member. In this case, it is possible to easily adjust the residence time of the carburizing atmosphere gas inside the direction regulating member by operating the damper.

The surface of the direction regulating member or the surface of the induction heating coil is preferably configured as a reflective layer that reflects radiant heat from the work to the work side space.
In this case, since the radiant heat from the work can be reflected to the work side space by the reflective layer, heat exchange between the radiant heat and the induction heating coil and the shell wall of the processing chamber can be suppressed. For this reason, the heat loss at the time of the carburizing process of a workpiece | work can be suppressed more effectively.

  According to the carburizing apparatus of the present invention, heat loss during the carburizing process of the workpiece can be suppressed and the energy consumption required for the carburizing process can be reduced, so that the carburizing process cost can be reduced.

It is sectional drawing which shows the principal part of the carburizing processing apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the principal part of the carburizing processing apparatus which concerns on other embodiment of this invention. It is sectional drawing which shows the principal part of the carburizing processing apparatus which concerns on other embodiment of this invention. It is sectional drawing which shows the principal part of the conventional carburizing processing apparatus.

Hereinafter, the carburizing apparatus of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing a main part of a carburizing apparatus according to an embodiment of the present invention. In FIG. 1, a carburizing apparatus 1 includes a processing chamber 10 in which a work W made of steel such as low carbon steel or low carbon alloy steel is set, an induction heating coil 20 for induction heating the work W, and a carburizing atmosphere gas. A cylindrical direction regulating member 31 that regulates the flow direction of the gas, and a carburizing atmosphere gas that has passed through the inside of the direction regulating member 31 are introduced, and the carburizing atmosphere gas is supplied to the shell wall 11 of the processing chamber 10 and the direction regulating member. A recirculation regulating member 35 that recirculates a predetermined amount to the space between the gas chamber 31, a gas supply path 50 that supplies carburizing gas into the processing chamber 10, an exhaust gas flow path 60 that discharges the carburizing atmosphere gas in the processing chamber 10 I have.

The processing chamber 10 includes a shell wall 11 having an open bottom and a disk-shaped bottom plate 14 that closes the bottom of the shell wall 11 so as to be openable. The shell wall 11 is such that the upper end of a cylindrical peripheral wall 12 is closed by a disk-shaped ceiling wall 13. The peripheral wall 12 and the ceiling wall 13 are each formed of a heat resistant material such as quartz or heat resistant steel.
The bottom plate 14 can be moved up and down by a lifting mechanism (not shown), and the bottom portion of the shell wall 11 can be closed at the rising end position.

The induction heating coil 20 is disposed inside the processing chamber 10. The induction heating coil 20 has a spiral shape that can surround the outer periphery of the workpiece W, and the workpiece W is set inside the inner periphery thereof. The induction heating coil 20 can induction-heat the workpiece W to a desired temperature by supplying a high-frequency current.
The workpiece W is supported by a support member (not shown) that can be raised and lowered. The support member moves up and down integrally with the bottom plate 14 to supply the work W to the inner periphery of the induction heating coil 20 and to carry the supplied work W to the lower side of the processing chamber 10. Can do.

The direction regulating member 31 includes a first cylindrical portion 32 that surrounds the outer periphery of the workpiece W, and a tapered cylindrical portion 33 that is connected to the upper end portion of the first cylindrical portion 32 and gradually decreases in diameter upward. , And a second cylindrical portion 34 connected to the upper end portion of the tapered cylindrical portion 33. The material of these direction regulating members 31 is selected from materials that are not induction-heated, and is preferably quartz or ceramics.
The direction regulating member 31 is disposed in a space between the workpiece W and the induction heating coil 20, and partitions the workpiece W from the shell wall 11 of the processing chamber 10 and the induction heating coil 20. Thereby, the carburizing atmosphere gas heated by the radiant heat of the heated workpiece W is restricted from flowing from the workpiece W side to the induction heating coil 20 side and the shell wall 11 side (see arrow A in FIG. 1). . Therefore, heat exchange between the carburizing atmosphere gas and the shell wall 11 and the induction heating coil 20 can be suppressed, and heat loss during the carburizing process can be reduced.

  The reflux regulating member 35 is a box-shaped member that divides a part of the space on the ceiling wall 13 side of the processing chamber 10, and the top plate portion is shared by the ceiling wall 13. In addition, an opening is provided at the bottom of the reflux restriction member 35, and the second cylindrical portion 34 is fitted into the opening. Thereby, the carburizing atmosphere gas rising inside the direction regulating member 31 can be introduced into the reflux regulating member 35. Further, the side wall portion 35a is provided with a plurality of discharge holes 35b over the entire circumference thereof. Further, the inside of the recirculation restriction member 35 communicates with the exhaust gas passage 60 so that a part or all of the carburizing atmosphere gas introduced into the inside can be discharged through the exhaust gas passage 60. It has become.

  The sum total of the opening area of each discharge hole 35b is set to an appropriate value according to characteristics such as the material and surface area of the workpiece W. The sum of the opening areas is set for each workpiece W in accordance with the characteristics of the workpiece W in a range where the reflux rate of the carburizing atmosphere gas is 0 to 100%. Here, the “recirculation rate” refers to the amount X of the processing chamber 10 with respect to the amount X of the carburizing atmosphere gas introduced into the reflux regulating member 35 excluding the carburizing atmosphere gas discharged through the exhaust gas passage 60. The ratio (X / Y) of the amount Y of carburizing atmosphere gas to be returned to the space between the shell wall 11 and the direction regulating member 31. “Reflux rate 0%” means that the carburized atmosphere gas used in the carburizing process of the workpiece W is discharged 100% through the exhaust gas flow channel 60, and “reflux rate 100%” means the carburization of the workpiece W. It means that the gas discharged through the exhaust gas flow path 60 in the carburized atmosphere gas after being used in the treatment is zeroed and refluxed 100%.

As described above, according to the reflux restriction member 35, the sum of the opening areas of the respective discharge holes 35b is set to an appropriate value in accordance with characteristics such as the material and surface area of the workpiece W. The amount of the carburizing atmosphere gas returned to the space between the shell wall 11 and the direction regulating member 31 can be optimized. For this reason, the temperature and / or composition of the carburizing atmosphere gas in the processing chamber 10 can be set to an appropriate value according to the characteristics of the workpiece W. Therefore, the carburizing process of the workpiece W can be performed uniformly and efficiently.
When the opening degree of the discharge hole 35b is adjusted so that the reflux rate exceeds 0%, the carburizing atmosphere gas introduced into the reflux restriction member 35 is passed through the discharge hole 35b and the shell wall of the processing chamber 10 is passed. 11 and the direction regulating member 31 can be discharged, refluxed, and supplied again to the vicinity of the workpiece (see arrow B in FIG. 1). In this case, since the unreacted gas in the carburizing atmosphere gas can be reused, the carburizing cost can be reduced.

Connected to the processing chamber 10 is a gas flow path 50 for supplying a carburizing gas comprising methane gas as a hydrocarbon gas and nitrogen gas as a dilution gas into the processing chamber 10. A hydrocarbon gas cylinder 51 for supplying methane gas and a dilution gas cylinder 52 for supplying nitrogen gas are connected to the gas flow path 50, respectively.
Further, the carburizing apparatus 1 is provided with a sensor 70 for detecting the temperature and composition of the carburizing atmosphere gas in the processing chamber 10. For example, the detection unit at the tip of the sensor 70 is disposed at the position illustrated in FIG. 1, but is disposed in a space between the workpiece W and the direction regulating member 31 as illustrated in FIGS. 2 and 3. May be.
Since the temperature and composition of the carburizing atmosphere gas used for the carburizing process of the workpiece W can be monitored by the sensor 70, the temperature and composition of the carburizing atmosphere gas can be appropriately adjusted in accordance with characteristics such as the material and surface area of the workpiece W. Can be adjusted to any value. The sensor 70 may detect either the temperature or the composition of the carburizing atmosphere gas.

According to the carburizing apparatus 1 having the above configuration, the carburizing atmosphere gas inside the direction regulating member 31 flows to the shell wall 11 side and the induction heating coil 20 side of the processing chamber 10 by the direction regulating member 31. Since it regulates, heat exchange between the carburizing atmosphere gas and the shell wall 11 of the processing chamber 10 and the induction heating coil 20 can be effectively suppressed.
Therefore, according to the carburizing apparatus 1 of the present invention, it is possible to suppress the heat loss during the carburizing process of the workpiece W and reduce the energy consumption required for the carburizing process. Specifically, it is confirmed that the carburizing apparatus 1 of the present invention can reduce the heat loss during the carburizing process by about 17 to 23% as compared with the conventional carburizing apparatus in which the direction regulating member 31 is not installed. Has been. Therefore, the carburizing apparatus 1 of the present invention can reduce the carburizing cost.

As shown in FIG. 2, at least the induction heating coil 20 side surface of the direction regulating member 31 may be configured as a reflective layer 31 a that reflects radiant heat from the workpiece W. The reflective layer 31a can be formed, for example, by performing gold plating or the like on the surface of the base material of the direction regulating member 31.
Further, as shown in FIG. 3, the induction heating coil 20 may be configured such that the surface of the induction heating coil 20 is a reflective layer 22 that reflects radiant heat from the workpiece W. The reflective layer 22 can also be formed by performing gold plating or the like on the surface of the base material of the induction heating coil 20.

  In this case, since the radiant heat from the work W can be reflected to the work W side space by the reflective layer 31a of the direction regulating member 31 or the reflective layer 22 of the induction heating coil 20, the radiant heat and the induction heating coil can be reflected. 20 and the heat exchange with the shell wall 11 of the processing chamber 10 can be further suppressed. For this reason, the heat loss at the time of the carburizing process of the workpiece | work W can be suppressed more effectively. Specifically, when the reflective layer 31a is formed on the direction regulating member 31, the heat loss during the carburizing process can be reduced by about 8 to 12% compared to the case where the reflective layer 31a is not formed. It has been confirmed.

In the carburizing apparatus 1, as shown in FIGS. 2 and 3, the residence time of the carburizing atmosphere gas inside the direction regulating member 31 is set inside the second cylindrical portion 34 of the direction regulating member 31. A damper 38 (residence time adjusting member) for adjustment may be provided. The damper 38 can change the opening ratio inside the second cylindrical portion 34 by rotating the rotation shaft 38 a from the outside of the processing chamber 10. The residence time of the carburizing atmosphere gas inside can be adjusted to be appropriate according to the characteristics of the workpiece W. Therefore, the carburizing process of the workpiece W can be performed more uniformly and efficiently.
Further, the residence time can be appropriately adjusted by adjusting the total amount of the recirculation amount and the exhaust amount of the carburizing atmosphere gas by the damper 38.
The rotating shaft 38a of the damper 38 may be remotely operated by a driving means such as a stepping motor, in addition to being manually rotated.

  In this embodiment, the damper 38 is used as the residence time adjusting member, and the residence time of the carburizing atmosphere gas inside the direction regulating member 31 can be variably adjusted. However, instead of the damper 38, the second cylindrical portion is used. By appropriately selecting the diameter of 34, the second cylindrical portion 34 may also serve as a residence time adjusting member.

  Further, in the carburizing apparatus 1, an appropriate temperature and composition value of the carburizing atmosphere gas corresponding to characteristics such as the material and surface area of the workpiece are obtained in advance, and the values from the sensor 70 are maintained so that these values can be maintained. The exhaust hole 35b may be feedback-controlled using a signal as an input to automatically adjust the amount of reflux of the carburizing atmosphere gas to the processing chamber 10.

DESCRIPTION OF SYMBOLS 1 Carburizing apparatus 10 Processing chamber 11 Shell wall 20 Induction heating coil 22 Reflective layer 31 Direction control member 31a Reflective layer 35 Reflux control member 35b Outlet 38 Damper (residence time adjustment member)
50 Gas flow path 70 Sensor W Workpiece

Claims (5)

A carburizing apparatus for carburizing a steel workpiece,
A processing chamber for setting the workpiece inside;
An induction heating coil that is installed inside the processing chamber and surrounds and heats the workpiece;
A gas supply path for supplying a carburizing gas into the processing chamber;
An exhaust gas passage for exhausting the carburizing atmosphere gas in the processing chamber;
A cylindrical shape that regulates the flow of the carburizing atmosphere gas that divides the workpiece, the shell wall of the processing chamber, and the induction heating coil from the workpiece side to the shell wall side of the processing chamber and the induction heating coil side. A direction regulating member;
A carburizing apparatus characterized by comprising:   A recirculation restriction member is provided that introduces the carburizing atmosphere gas that has passed through the inside of the direction restriction member and causes the carburizing atmosphere gas to flow at a predetermined flow rate to a space between the shell wall of the processing chamber and the direction restriction member. The carburizing apparatus according to 1.   The carburizing apparatus according to claim 1, further comprising a residence time adjusting member that adjusts a residence time of the carburizing atmosphere gas inside the direction regulating member.   The carburizing apparatus according to claim 3, wherein the residence time adjusting member is a damper capable of variably adjusting the flow rate of the carburizing atmosphere gas introduced from the inside of the direction regulating member to the inside of the reflux regulating member.   The carburizing apparatus according to any one of claims 1 to 4, wherein a surface of the direction regulating member or a surface of the induction heating coil is configured as a reflective layer that reflects radiant heat from a work to a work side space.

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