JP2013087359A - Apparatus for quenching material to be treated - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the difference of quenching strain at the upper and down stages when materials to be treated, placed as multi-layers on the multi stages on a placing table, are dipped into a cooling vessel for cooling.SOLUTION: When a pallet 80 descends with an elevator 15, the cooling vessel 100 is arranged with stirring devices 104a, 104b which cause circulating flows 102a, 102b facing the lower part along the up and down axial line 18 to the cooling oil 102 at the descending position in the cooling vessel 100, and ducts 108a to 108e, which form the stream toward the stirring device from the side of the up and down axial line 18, are arranged in the symmetrical position on the bottom surface in the cooling vessel 100.

Description

  The present invention relates to a quenching apparatus for workpieces such as gears used in a driving force transmission system of a vehicle.

  Conventionally, a quenching apparatus for quenching steel machined parts (processed objects), etc., is a cooling system in which a coolant such as quenching oil for rapidly cooling the processed objects heated to the quenching temperature is stored. Has a tank. The quenching apparatus places a heated object to be processed on a fork of a lifting device provided in the quenching apparatus via a mounting table, and immerses the whole fork in a cooling liquid to quench (rapid cooling). )It is carried out.

  The cooling tank of the quenching apparatus has a cooling liquid discharge port at the bottom of the cooling tank, and the cooling liquid is circulated in the cooling tank by discharging the cooling liquid upward from the discharge port. The device is arranged. In this circulation device, the flow of the cooling liquid from the discharge port is guided to the workpiece immersed in the cooling liquid, and quenching is performed while maintaining a predetermined cooling rate (see Patent Document 1).

In this type of quenching apparatus, since the object to be processed is immersed in the cooling liquid together with the fork while the object to be processed is placed on the fork, the flow of the cooling liquid upward from the bottom side of the cooling tank is hindered by the fork. In some cases, the flow of the cooling liquid cannot be evenly guided to the object to be processed.
For example, in the case where a plurality of objects to be processed such as annular members are stacked in a basket and the objects to be processed arranged in three dimensions are heat-treated, the flow of the cooling liquid cannot be evenly guided to the objects to be processed. In addition, the cooling rate of each object to be processed in the basket becomes non-uniform, and the variation in the amount of deformation and distortion generated in the object to be processed such as each annular member increases.

  In this way, when the variation in the amount of deformation or strain generated in the workpiece increases, the deformation or strain of the workpiece such as each annular member is removed by turning or polishing in the processing step after heat treatment, sizing, etc. When removing deformation and strain by plastic working, the processing time may take a long time, which may cause a reduction in production efficiency.

  As a countermeasure for such a factor, setting is made so that the flow of the coolant is evenly guided by adjusting the conditions such as the flow rate and flow rate of the coolant. That is, variation in the amount of deformation and distortion is suppressed by setting the environmental conditions such as the flow rate and flow rate after cooling to a predetermined number and arrangement, and appropriate values.

  However, when heat-treating other objects to be processed having different sizes, numbers, and arrangements, it is necessary to change environmental conditions such as the flow rate and flow rate of the cooling liquid. It is necessary to readjust the temperature of the coolant. As described above, since suitable environmental conditions vary depending on the size and number of objects to be processed, it takes a lot of work time to appropriately adjust the environmental conditions according to the objects to be processed. Has not been resolved yet.

  As a quenching apparatus for solving the above problems, there is an oil tank in which a coolant is stored, a mounting table on which an object to be processed is placed, and a lifting means for immersing the object in the coolant. And a rectifying plate that has a discharge port for discharging the cooling liquid upward at the bottom of the oil tank and further circulates the cooling liquid, and guides the flow of the cooling oil to the mounting table above the fork. The thing provided with (refer patent document 2) is known.

JP-A-2005-350756 JP 2010-7146 A

However, the cooling tank of the quenching apparatus described in Patent Document 2 includes a discharge port for discharging the coolant upward at the bottom of the cooling tank, and also allows the cooling oil to flow to the mounting table above the fork. The baffle plate which leads to is provided.
For this reason, in the cooling tank in which the mounting table on which the workpiece is placed is immersed, a circulating flow of the cooling liquid is formed from the lower side to the upper side.

As described above, Patent Document 2 can solve the problem of non-uniformity of the coolant flow of Patent Document 1, but when a plurality of objects to be processed are stacked on the mounting table, the upper substrate In the processed object, the flow of the cooling liquid directed upward is hindered by the lower object to be processed, so that the flow of the individual processed objects stacked is uneven.
As a result, quenching distortion occurs in each workpiece to be stacked and mounted on the mounting table, and there is a problem that the difference in quenching distortion becomes significant each time the stacking is performed in multiple stages.

  In view of the problems of the prior art, the present invention reduces the difference in quenching distortion in the upper and lower stages when the workpieces stacked and placed in multiple stages in a flat state on the mounting table are immersed in the cooling bath and cooled. The purpose is to do.

  In order to solve the above-described problems, a workpiece quenching apparatus according to the present invention cools a workpiece after heat treatment, which is supported by a mounting table and stacked in multiple stages in a flat state, by lowering a lifting device. In the quenching apparatus for the workpiece to be quenched by being immersed in the cooling oil in the tank, the cooling tank is raised and lowered to the cooling oil at the lowered position in the cooling tank when the mounting table is lowered by the lifting device. A stirrer that generates a downwardly flowing circulation flow along the axis is disposed, and a flow path that guides the circulating flow generated by the stirrer downward at a position where the mounting table descends is disposed. And

  According to this invention, it is set as the structure which has arrange | positioned the stirring apparatus which produces the circulating flow of the cooling oil which faces below along the raising / lowering axis line in the descent | fall position in a cooling tank. Thereby, when the mounting table is lowered by the lifting device, the stirring device is activated, and a flow path that guides the circulating flow generated by the stirring device downward at the position where the mounting table is lowered is disposed. Since a lubricating flow directed downward along the lifting axis is generated at the mounting table lowering position in the cooling tank, the flow direction of the cooling oil is the same as the lowering direction of the mounting table. Therefore, the difference in quenching distortion can be eliminated because the difference in the flow velocity of the cooling oil with respect to the individual workpieces stacked in the upper and lower stages in a flat state on the mounting table is reduced.

In the present invention, it is preferable that the elevating device activates the stirring device before starting to lower the mounting table.
According to such a configuration, the stirrer is activated by a command (for example, when the intermediate door of the carry-out purge chamber is closed) before the mounting table on which the workpieces are stacked starts to descend. Before being immersed in the cooling tank, a circulating flow is formed which faces downward along the lifting axis. Thereby, by the time the mounting table is immersed in the cooling bath, a circulating flow in the same direction that substantially matches the descending speed of the lifting device suitable for the quenching condition is formed.

  Preferably, in the present invention, the mounting table described above is a column that supports a plurality of objects to be stacked vertically by inserting an attachment hole standing on the mounting table and formed at the center of the object to be processed. A cylindrical collar that is inserted and supported by the support column between the workpieces to be stacked, and is supported by the upper end surface of the cylindrical collar, with the upper and lower stages spaced apart so as to restrict the lateral movement of the upper workpiece. It is characterized by comprising a position regulating jig that supports lamination.

  According to such a configuration, since the upper and lower workpieces are stacked with a predetermined interval by the cylindrical collar and the position regulating jig, the cooling oil is smoothly supplied between the workpieces, Depending on the quenching conditions, it can be replaced with a cylindrical collar of different length.

  Preferably, in the present invention, the position restricting jig is formed so that an insertion hole through which the support column is inserted is formed at the center, and the upper surface of the peripheral edge of the insertion hole is evenly arranged so as to fit into the inner periphery of the mounting hole of the upper workpiece. A plurality of protruding portions, and a plurality of contact pieces equally arranged on the circumference to support the lower surface of the peripheral edge of the mounting hole of the upper workpiece on the outer peripheral upper surface of the protruding portion. And

  According to this configuration, the position restriction jig is sandwiched between the upper and lower workpieces together with the cylindrical collar, and the position restriction jig is formed with an insertion hole through which the support column is inserted at the center, and the peripheral upper surface of the insertion hole. A plurality of protrusions equally arranged to fit in the inner periphery of the mounting hole of the upper processing object, and on the circumference to support the lower surface of the peripheral edge of the mounting hole of the upper processing object on the outer peripheral upper surface of the protrusion Since it comprises a plurality of contact pieces that are evenly arranged, it is possible to prevent lateral displacement of a plurality of objects to be stacked, and to improve the centripetal property with respect to the column. As a result, the plurality of objects to be stacked are stably supported.

As described above, according to the present invention, the cooling tank of the workpiece quenching apparatus includes the cooling tank in the cooling tank when the workpieces are stacked in multiple stages in a flat state and lowered by the lifting device. A stirrer is arranged to cause the cooling oil in the lowered position to generate a circulating flow directed downward along the lifting axis.
As a result, the flow direction of the lubricating flow in the lifting / lowering axis can be substantially coincided with the descending direction of the lifting / lowering device by starting the stirring device. Thereby, the difference in flow rate between the upper and lower workpiece to be stacked on the mounting table and the circulating oil is reduced, so that the quenching distortion difference can be reduced.
In addition, an appropriate flow rate of the cooling oil can be obtained by setting the rotation speed of the agitator according to the quenching conditions.

It is a mimetic diagram showing the whole hardening object quenching device concerning one embodiment of the present invention. It is sectional drawing which similarly shows the inside of the cooling tank of a quenching apparatus. It is explanatory drawing of the aspect by which the same flow is formed similarly to the descent | fall direction of the pallet which similarly laminated | stacked the to-be-processed object for every predetermined space | interval in the cooling tank inside. It is a figure which similarly shows the support jig | tool which supports the to-be-processed object laminated | stacked by the flat placement on a pallet for every predetermined interval. It is explanatory drawing which shows the aspect which enabled adjustment of the space | interval of the to-be-processed object laminated | stacked on a pallet according to quenching conditions. It is a time chart which shows the fall start time of a raising / lowering apparatus, and the rotation start time of a stirring apparatus.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, as long as there is no specific description, the dimensions, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.

FIG. 1 is a schematic view showing the entire workpiece quenching apparatus according to an embodiment of the present invention. The quenching apparatus 1 is an apparatus for simultaneously quenching (rapid cooling) a plurality of objects to be heat treated. The quenching apparatus 1 includes a carburizing furnace 10 and a cooling bath 100.
As an object to be processed according to the embodiment of the present invention, for example, a gear W serving as a final drive gear of a transmission is employed.

A carry-in purge chamber 12 and a carry-out purge chamber 14 are disposed on the inlet side and the outlet side of the carburizing furnace 10.
The carry-in purge chamber 12 is connected to a transfer device 200 for carrying a plurality of gears W stacked and placed in a flat state on a mounting table (pallet) 80, and is connected to the inlet side of the carry-in purge chamber 12. A carry-in door 12a that shuts off from outside air is provided so as to be openable and closable.

  A carry-out device 220 for carrying out the hardened gear W is also connected to the carry-out purge chamber 14 which will be described later, and a carry-out door 14b that shuts off the outside air is provided at the outlet side of the carry-out purge chamber 14 so as to be openable and closable. Yes. In the carry-in and carry-out purge chambers 12 and 14, intermediate doors 12b and 14a that block communication with the carburizing furnace 10 are provided to be openable and closable.

  In the carry-in purge chamber 12, a large number of gears W stacked and placed on the pallet 80 received from the transfer device 200 are heated to about 400 ° C. in an atmosphere isolated from the outside air to perform a degreasing process or the like. Pre-processing is performed. Note that the carry-in purge chamber 12 is not limited to this, and it is sufficient that the atmosphere inside the purge chamber 12 can be replaced.

The carburizing furnace 10 is a temperature rising chamber capable of temperature control. Here, the gear W is preheated to about 900 ° C. in an atmosphere of a carrier gas such as RX gas. That is, in the carburizing zone inside the carburizing furnace 10, a carrier gas such as RX gas and an enriched gas such as hydrocarbon gas are supplied.
The gear W on the pallet 80 carried out from the carry-in purge chamber 12 into the carburizing furnace 10 is transferred to the carry-out purge chamber 14 and is approximately 800 ° C. in each zone in the carburizing gas atmosphere. Carburization is performed while being heated to 900 ° C. and approximately 900 ° C.

That is, the carbon component adheres to the surface of the gear W in the process of transferring the gear W on the pallet 80 that is transferred inside the heated carburizing furnace 10 over 8 hours to 10 hours.
In the temperature lowering zone disposed behind the carburizing furnace 10, the gear W is cooled to about 850 ° C. so as to be equal to the temperature before the quenching process and is soaked.

  In the carry-out purge chamber 14 provided at the rear end of the carburizing furnace 10, an elevator 15 to be introduced into a cooling tank 100 (described later) for quenching and quenching the heated gear W after the carburizing treatment is moved up and down. It is provided as possible.

Next, it attaches to the cooling tank 100 and demonstrates with reference to FIG. 1A is a front cross-sectional view of the cooling bath 100, and FIG. 1B is a cross-sectional view of the cooling bath 100 taken along the line AA.
The cooling tank 100 is filled with cooling oil 102 at approximately 100 ° C., and the gear W on the pallet 80 transported from the carburizing furnace 10 to the discharge purge chamber 14 is lowered at the approximate center of the cooling tank 100. An elevator 15 is disposed for being immersed in the cooling oil 102 inside the cooling bath 100.

The elevator 15 is provided with a horizontal support base 16 formed in a lattice pattern in plan view for supporting a pallet 80 on which a plurality of gears W are stacked and mounted so as to be moved up and down by a drive source (not shown).
On the top surface of the top plate 112 of the cooling tank body 110, two stirring devices 104a and 104b are installed at substantially symmetrical positions on both sides of the lifting axis 18 on which the elevator 15 moves up and down.
Below the two agitating devices 104a and 104b, a pair of agitating blades 105a and 105b that are rotationally driven in the same direction by two motors M1 and M2 are provided at a substantially intermediate position in the height direction of the cooling tank body 110. ing.

Inside the cooling tank main body 110, a duct for causing a flow of the cooling oil 102 generated by the rotation of the pair of stirring blades 105a and 105b as a circulating flow is disposed.
That is, as the duct, at the center of the bottom surface of the cooling bath main body 110, the pair of central ducts 108a along the lifting axis 18 and the bottom surface of the cooling bath main body 110 corresponding to both outer sides of the pair of stirring blades 105a and 105b are located upward. The guiding bottom ducts 108b and 108c are arranged symmetrically.

The central duct 108a has a branch plate 109 standing at the center and a curved surface facing outwards at the bottom. The bottom ducts 108b and 108c are formed with plate-like curved surfaces that rise upward from the bottom surface.
In addition, a pair of upper ducts 108d and 108e having a curved surface that is parallel to the rear surface side of the top plate 112 from the lower side are also disposed symmetrically on the rear surface of the top plate 112 of the cooling bath body 110.

Accordingly, when the two stirring devices 104a and 104b are activated simultaneously, the pair of stirring blades 105a and 105b rotate in the same direction, so that the cooling oil 102 flows upward on the axis of the pair of stirring blades 105a and 105b, respectively. Is formed.
The upward flow is guided by the pair of upper ducts 108d and 108e, and the cooling flows collide with each other at the substantially center, and a downward flow is formed along the lift axis 18, and the downward flow is the central branch plate 109. A flow branching left and right is formed by the central duct 108a.

The main part of the present invention is that a downward flow is generated in the cooling oil in the cooling tank along the lift axis of the elevator 15, and preferably the circulating flow moves downward during quenching. It is desirable that the flow rate and the speed at which the elevator descends are the same.
In order to obtain this state, the flow rate of the circulating oil reaches the same speed as the descending speed of the elevator by generating a circulating flow in the cooling oil of the cooling tank in advance before the elevator starts to descend. It turns out that it has the effect of improving quenching performance.

Therefore, the relationship between the time when the circulating flow is generated and the time when the descending movement of the elevator 15 is started will be described with reference to FIG.
FIG. 6 is a time chart showing the descent start timing of the lifting device and the rotation start timing of the stirring device.
In FIG. 6, the lowering start timing of the elevator 15 is the stirring devices 104a and 104b at the point P1 when the intermediate door 14a of the carry-out purge chamber 14 starts to close after the pallet 80 is carried into the carry-out purge chamber 14 from the carburizing furnace 10. In response to the rotation command signal, the stirring blades 105a and 105b start to rotate. As a result, in the cooling tank 100, circulating flows 102 a and 102 b are generated in the cooling oil 102 that are directed downward along the lift axis 18 of the elevator 15.

Next, a lowering command for the elevator 15 is output at a point P2 when the intermediate door 14a of the carry-out purge chamber 14 is closed to half of the entire stroke. The lowering operation of the elevator 15 is started after the time T ₀ has elapsed since the stirring blades 105a and 105b of the stirring devices 104a and 104b started to rotate. The elevator 15 reaches the descending end in the cooling tank in about 7 to 8 seconds after the descending operation is started.
That is, by starting the lowering operation of the elevator 15, the circulating flows 102 a and 102 b having a predetermined flow rate are generated in the cooling oil 102 in the cooling tank 100 until the pallet 80 is immersed in the cooling oil 102. The circulating flows 102a and 102b directed downward reach a flow velocity that matches the descending speed of the elevator 15.

Thus, the circulating flows 102 a and 102 b flow downward along the lifting axis 18 at the lowered position of the elevator 15 and circulate in the direction indicated by the dotted line in the cooling oil 102 in the cooling bath 100.
The circulating flows 102a and 102b flow downward on both sides of the gear W and between the gears W stacked in a plurality of stages on the upper surface of the pallet 80 while maintaining a predetermined interval as shown in FIG. 2 passes through a lattice-like support base 16 (see FIG. 2) supporting the above.

The elevator 15 in the lowered position has a stop time T of about 10 minutes, and during that time, when the gear W stacked and supported on the pallet is quenched, it again reaches the original carry-out purge chamber 14 in about 7 to 8 seconds. Ascended and carried out from the carry-out purge chamber 14 onto the carrying device 220 for carrying out.
Thus, the circulation flows 102a and 102b of the cooling oil 102 are formed on both sides of the gear W loaded in a plurality of stages on the pallet 80 in the same direction as the support base 16 moving downward by the elevator 15. Since the flow rate difference of the cooling oil 102 with respect to the individual gears W stacked in multiple stages is reduced, the difference in quenching distortion can be reduced.

Next, a description will be given with reference to FIGS. 4 and 5 with respect to a position regulating jig 90 that holds the plurality of gears W on the pallet 80 in a stable posture.
FIG. 4A is a view showing a position restricting jig 90 that supports gears W stacked and placed flat on a pallet at predetermined intervals, and FIG. 4B is a sectional view taken along line BB in FIG. 5 (a) is a plan view of the pallet, and (b) is a view showing a CC cross section of (a), and the interval between the gears W stacked and placed on the pallet according to the quenching condition is lengthened. It is explanatory drawing which shows the aspect made adjustable with different cylindrical collars.

  4 (a) and 4 (b), the position regulating jig 90 is inserted and supported by a column (see FIG. 5) erected on the pallet 80, and holds a plurality of gears W on the same axis. An inner ring 92 having an insertion hole 93 formed in the center and an outer ring 94 connected to the three arms 95a, 95b, and 95c arranged at 120 ° intervals on the outer periphery of the inner ring 92 are arranged concentrically. Further, centripetal projections 92a, 92b, and 92c (cross hatch portions) that are fitted into the inner periphery of the mounting hole Wa of the gear W protrude from substantially the intermediate upper surface of the three arms 95a, 95b, and 95c. Yes.

Further, on the upper surface of the outer ring 94 where the three arms 95a, 95b, and 95c do not exist, three circles are formed on the extension lines of the arms 95a, 95b, and 95c facing the protrusions 92a, 92b, and 92c. Arc-shaped contact pieces 94a, 93b, and 94c (cross-hatched portions) project.
The position regulating jig 90 formed in this way is in a state in which the protrusions 92a, 92b, and 92c are inserted into the inner periphery of the mounting hole Wa of the gear W when the gear W indicated by the phantom line is held. The lower surface Wb of the gear W is abutted and supported by the upper end surfaces of the abutting pieces 94a, 93b, 94c.

  5A and 5B, a plurality of (four) fitting holes 82 are formed on the top surface of the pallet 80 and arranged in a staggered manner. A cylindrical sleeve 84 is inserted into these fitting holes 82, and a column 85 having a circular cross section is vertically held in the sleeve 84.

Next, a procedure for stacking and supporting a plurality of gears W on the upper surface of the pallet 80 will be described with reference to FIG.
The diagram shown on the right side of FIG. 5B shows a state in which the plurality of gears W are stacked and supported on the support column 85 with the interval between the gears W widened.
First, the short cylindrical collar 96 inserted downward from the upper end of the column 85 is supported by the upper surface of the sleeve 84. Next, the position restricting jig 90 holding the gear W is inserted and lowered from the upper end of the support column 85 to contact and hold the upper end surface of the collar 96. The restriction jig 90 may be inserted and lowered first, and then the gear W may be lowered to hold the gear W on the restriction jig 90.

When a long collar 97 inserted from the upper end of the column 85 is abutted and held on the upper surface of the inner ring 92 of the position restricting jig 90 holding the gear W positioned at the lowermost stage, the upper end surface of the collar 97 is next. The lower surface of the inner ring 92 of the position restricting jig 90 that holds the gear W located at this stage is held in contact.
Thereafter, the position regulating jig 90 holding the gear W by the same procedure is stacked and held up to the uppermost stage in a state of being inserted on the support column 85 at predetermined intervals by the collar 97 having a fixed length.

The diagram shown on the left side of FIG. 5B shows a state where a plurality of gears W are stacked and supported on the support column 85 with the interval between the gears W narrowed.
First, the short cylindrical collar 98 inserted downward from the upper end of the support column 85 is supported in contact with the upper surface of the sleeve 84. Next, the position restricting jig 90 holding the gear W is inserted and lowered from the upper end of the support column 85 to contact and hold the upper end surface of the collar 98.
When a medium-sized collar 99 inserted downward from the upper end of the support 85 is abutted and held on the upper surface of the inner ring 92 of the position regulating jig 90 holding the gear W positioned at the lowermost stage, the upper end surface of the collar 99 The lower surface of the inner ring 92 of the position restricting jig 90 holding the gear W positioned at the next stage is held in contact.

Thereafter, the position restricting jig 90 holding the gear W by the same procedure is stacked and held up to the uppermost stage in a state of being inserted on the column 85 at predetermined intervals by the collar 99 having a predetermined length.
In this way, a plurality of gears W are stacked and held on the pallet 80 shown in the left figure at intervals shorter than those shown in the right figure by exchanging the collars having different lengths according to the quenching conditions. It will be.

  By adopting a loading mode in which the collars having different lengths are exchanged for the plurality of gears W, an appropriate flow rate according to the descending direction and speed of the pallet 80 as indicated by an arrow between the loaded gears W, By introducing the cooling oil 102 at a flow rate, it is possible to obtain optimum quenching conditions in which the quenching strain difference is reduced in the upper and lower stages.

  According to the present invention, the difference in quenching strain can be reduced because the flow rate difference between the upper and lower workpieces and the circulating oil that are stacked on the mounting table is reduced, so that the difference in quenching strain can be immersed in the cooling oil in the cooling tank. The present invention can be applied to a quenching apparatus for a workpiece to be quenched.

1 Quenching device 15 Elevator (lifting device)
18 Lifting axis 80 Pallet (mounting table)
85 Prop 90 Position restriction jigs 92a, 92b, 92c Protruding portion 93 Insertion holes 94a, 93b, 94c Abutting pieces 96-99 Color (cylindrical color)
DESCRIPTION OF SYMBOLS 100 Cooling tank 102 Cooling oil 102a, 102b Circulating flow 104a, 104b Stirrer 108a-108e Center duct, bottom duct, upper duct (flow path)
W gear (object to be processed)

Claims (4)

In a quenching apparatus for a workpiece that is supported by a mounting table and subjected to quenching by immersing workpieces after heat treatment, which are stacked in multiple stages in a flat state, in a cooling oil in a cooling tank by descending the lifting device ,
The cooling tank is provided with a stirring device for generating a circulating flow downward along the lifting / lowering axis in the cooling oil at the lowered position in the cooling tank when the mounting table is lowered by the lifting / lowering device. A workpiece quenching apparatus, wherein a flow path for guiding a circulating flow generated by the apparatus downward is provided at a position where the mounting table descends.   2. The workpiece quenching apparatus according to claim 1, wherein the elevating device starts the stirring device before starting to lower the mounting table. 3.   The mounting table described above is between the support to be stacked and the support to be stacked by inserting a mounting hole that is erected on the mounting table and formed at the center of the processing object, and supports the plurality of processing objects. A cylindrical collar that is inserted and supported by the column, and a position regulating jig that is supported by the upper end surface of the cylindrical collar and that supports the stacking with the upper and lower stages spaced apart so as to regulate the lateral movement of the upper workpiece. The to-be-processed material hardening apparatus of Claim 1 consisting of these.   The position restricting jig includes a plurality of protrusions that are formed at the center so that an insertion hole is formed through which the support column is inserted, and are arranged uniformly on the upper surface of the periphery of the insertion hole so as to fit into the inner periphery of the attachment hole of the upper workpiece. The plurality of abutting pieces that are equally arranged on the circumference to support the lower surface of the peripheral edge of the mounting hole of the upper workpiece on the outer peripheral upper surface of the protrusion. Hardening equipment for workpieces.

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