JPH07216457A - Method for quenching of circular saw tip saw base metal and device therefor - Google Patents

Abstract

PURPOSE:To provide a method and device for quenching the circular saw tip saw base metal capable of reducing the quenching strain of base metal to a minimum and increasing the treatment capacity. CONSTITUTION:After plural base metals 8 are laminated, on the upper/lower surfaces thereof, electrodes 4, 5 having a diameter smaller than the outside diameter of the base metal 8 are abutted while applying pressure, the base metals 8 are nearly enclosed by a case 13, an inert gas is supplied into the case, and subsequently, the base metals 8 are quenched by supplying high-frequency current to the electrodes 4, 5. The base metals 8 are laminated mutually so as not to be lapped on their tip mounting parts arranged at their circumference parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of quenching a circular saw tip saw base metal and a device thereof, in which a chip is brazed and fixed to an outer peripheral portion of the base metal.

[0002]

2. Description of the Related Art Conventionally, a circular saw tip saw used for cutting grass, cutting wood, etc. has a disk-shaped base metal made of a material such as SKS and is formed on the outer peripheral portion of the base metal. A chip of cemented carbide is brazed and fixed to a chip mounting portion including a step portion and the like. And, the base metal is generally subjected to quenching treatment in order to prevent a buckling phenomenon,
As the apparatus, for example, a high frequency induction heating type quenching apparatus is known as disclosed in Japanese Patent Publication No. 3-40085.

This quenching apparatus comprises an upper die that can move up and down,
A lower die on which a mounting table is arranged is provided, and a heating coil connected to a high-frequency transformer is arranged between the upper and lower dies so that the heating coil can be moved back and forth by the transfer means. Then, after setting the base metal on the mounting table, the heating coil is positioned on the upper and lower surfaces of approximately half of the base metal, and while the base metal is rotated, the high frequency current is supplied from the high frequency transformer to the heating coil, Induction heating to a predetermined temperature. After that, the heating coil is withdrawn from between the molds, the upper mold is lowered, and the base metal heated by the upper and lower molds is pressed into a pressed state, and cooling oil is supplied in this state to rapidly cool the base metal. Let it harden.

[0004]

However, this quenching apparatus has a problem that quenching distortion is likely to occur in the base metal and the processing capacity is poor. That is, the base metal is induction-heated by the heating coil placed close to the base metal, and then the supply of the high-frequency current to the heating coil is stopped, the heating coil is withdrawn, and pressure is applied by the upper and lower molds. There is a case that quenching distortion occurs because there is a time lag from the pressurization to the pressurization and it is difficult to heat the base metal uniformly because induction heating and pressurization of the base metal are performed in the atmosphere. . In addition, it is necessary to set the base metal between the metal molds one by one and perform induction heating or the like, which results in inferior quenching capacity.

The present invention has been made in view of the above circumstances, and a method and apparatus for quenching a circular saw tip saw base metal capable of minimizing the quenching distortion of the base metal and improving the processing capacity. To provide.

[0006]

In order to achieve the above object, a method for quenching a circular saw tip saw base metal according to claim 1 is
After stacking multiple bases and contacting disc-shaped electrodes with an outer diameter smaller than the outer diameter of the bases on the upper and lower surfaces while applying pressure, the outer periphery of the bases is sealed in a case It is characterized in that an inert gas is supplied into the case, and then a high frequency current is supplied to the electrodes to quench the base metal.

Further, in the quenching method according to the second aspect of the present invention, a disk-shaped electrode having an outer diameter smaller than that of the base metal and having a groove formed on a contact surface with the base metal is formed on the base metal. The method is characterized in that after contacting the upper and lower surfaces while applying pressure, an inert gas is supplied into the groove, and then a high frequency current is supplied to the electrodes to quench the base metal. Further, the quenching method according to claim 3 is characterized in that the base metals are stacked so that the chip mounting portions provided on the outer peripheral portion thereof do not overlap.

Further, in a quenching device for a circular saw tip saw base metal according to a fourth aspect of the present invention, the base metal is sandwiched by a predetermined pressure, and a pair of disc-shaped electrodes having an outer diameter smaller than the outer diameter of the base metal. An electrode moving means for moving at least one of the electrodes up and down, and a case that covers a portion of the base metal projecting from the electrode side surface in a substantially sealed state, or a groove provided on a contact surface of the electrode with the base metal. It is characterized by comprising a gas supply means for supplying an inert gas and a current supply means for supplying a high frequency current to the electrodes.

Further, the quenching apparatus according to claim 5 is characterized in that a recess is formed in a portion of the electrode corresponding to the shaft hole of the base metal. Is formed in a spiral shape. Further, the quenching apparatus according to claim 7 is characterized in that the electrode is provided integrally with the case.

[0010]

According to the method of quenching a circular saw tip saw base metal according to claim 1, first, an electrode having a diameter smaller than that of the base metal is brought into contact with the upper and lower surfaces of the stacked base metal while applying pressure. , A portion of the base metal protruding from the side surface of the electrode is covered with a case in a substantially sealed state. Then, after supplying an inert gas into the case to make it non-oxidized, a high-frequency current is supplied to the electrodes. Since the base metal is heated by electric current in a non-oxidized state and is pressed at the same time as this heating, quenching strain can be suppressed to a minimum. Since multiple base metals are processed at the same time, the processing capacity is also improved.

Further, in the quenching method of the present invention, an inert gas is supplied into the groove formed on the contact surface of the electrode with the base metal so as to be in an unoxidized state, and a high frequency current is supplied to the electrode. To do. The base metal can heat only a necessary portion thereof, so that quenching distortion can be further prevented, and a case or the like is not required, so that the structure is simplified. Further, according to the quenching method of claim 3, since the chip mounting portions formed on the outer peripheral portion of the base metal are stacked so as not to overlap each other, current concentration on the outer peripheral portion of the base metal is suppressed, and the outer peripheral portion of the base metal is suppressed. Overheating is prevented.

Further, according to the quenching device for a circular saw tip saw base metal according to the present invention, a plurality of base metals are sandwiched between a pair of electrodes in a pressurized state and protruded from the side surface of the base metal electrode. An inert gas is supplied by a gas supply means into a case in which a portion is covered in a substantially sealed state or into a groove formed in a contact surface of the electrode with the base metal so as to be in an unoxidized state. In this state, a high-frequency current is supplied to the electrodes by the current supply means, and a plurality of base metals stacked on each other are electrically heated to be quenched. Since the base metal is heated in a non-oxidized state, quenching distortion can be suppressed to a minimum, and a plurality of base metals can be processed at one time, improving the processing capacity.

Further, in the quenching apparatus according to a fifth aspect of the present invention, since the concave portion is formed in a portion of the electrode corresponding to the shaft hole of the base metal, heating around the central portion of the base metal is prevented. In the quenching apparatus described in 6, the spiral groove enables heating only a necessary portion of the base metal. Further, in the quenching apparatus according to the seventh aspect of the present invention, by integrating the electrode and the case, the work of setting the base metal can be facilitated and the configuration of the apparatus can be simplified.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a quenching device for a circular saw tip saw base metal according to the present invention. In FIG. 1, the quenching apparatus 1 has a lower electrode 4 installed on a base 2 via a heat insulating material 3, and an upper electrode 5 arranged so as to face the lower electrode 4. The upper electrode 5 is connected to the electrode moving device 7 via the drive shaft 6 and moves up and down by the operation of the electrode moving device 7.

The lower electrode 4 and the upper electrode 5 are formed in a disk shape having a diameter smaller than the outer diameter of the base metal 8 to be quenched, and a shaft hole 9 of the base metal 8 is formed in the central portion of the upper electrode 5. Large diameter recess 10
Are formed. Further, the insides of the lower electrode 4 and the upper electrode 5 are hollow so that the cooling liquid is circulated and supplied at the time of energization, and the lower electrode 4 and the upper electrode 5 are connected to a current generator 12 that generates a high frequency current. ing.

Between the lower electrode 4 and the upper electrode 5, a plurality of base metals 8 stacked as described below are arranged.
A ring-shaped case 13 is arranged at the portions protruding from the side surfaces of the electrodes 4, 5. The case 13 is divided into two case bodies 13a and 13b, and
A case moving device 15 is connected to 3b. Then, the case 13 is moved by the operation of the case moving device 15 so that the case bodies 13a and 13b are moved as shown by the chain double-dashed line in FIG. The case 13 has an inner peripheral surface formed in the same shape as the outer peripheral surfaces of the electrodes 4 and 5, and a concave portion 14 for accommodating the protruding portion of the base metal 8 is formed on the inner peripheral surface. In addition, at the joint portion of the case bodies 13a and 13b,
The step portion 16 (see FIG. 2) is formed.

Further, the case bodies 13a and 13b are respectively provided with a supply hole 17 and a discharge hole 18 for communicating the recess 14 with the outside, and a supply valve 19 is arranged in the supply hole 17 and a discharge hole 18 is provided. A discharge valve 2 that operates above a certain pressure
0 is set. The supply valve 19 is a gas supply device 21.
Gas is supplied to the supply valve 19 and the supply hole 1.
The gas and the air in the case 13 are supplied to the inside of the concave portion 14 of the case 13 via 7 and are discharged to the outside via the discharge hole 18 and the discharge valve 20. In addition, the electrode moving device 7, the current generator 12, the case moving device 15, the gas supply device 21.
Are connected to the control device 22. The control device 2
2 may be provided integrally with the current generator 12 or the like.

Next, a method of quenching the base metal 8 by the quenching apparatus 1 will be described. First, according to the control signal of the control device 22, the electrode moving device 7 and the case moving device 15 are operated to raise the upper electrode 5 by a predetermined distance, and the case bodies 13a and 13b are moved to the position of the chain double-dashed line in FIG. To move. In this state, a plurality of, for example, five base metals 8 are stacked and set on the lower electrode 4. At this time, in the base metal 8, as shown in FIG. 3, the step portions 8a (chip mounting portions) provided on the outer peripheral portion for fixing the chips 23 are arranged so that they are not at the same position in the vertical direction, that is, The step portions 8a are stacked by shifting them in the circumferential direction by a predetermined angle.

When the setting of the base metal 8 on the lower electrode 4 is completed, the electrode moving device 7 is operated by the control signal of the control device 22 to press the base metal 8 with a predetermined pressure by the upper electrode 5. Then, the case moving device 15 is operated to bring the case bodies 13a and 13b into contact with the side surfaces in the direction of the lower electrode 4 and the upper electrode 5 with a predetermined pressure. As a result, the stepped portion 8 a protruding from the side surfaces of the electrodes 4 and 5 of the base metal 8 is located in the recess 14 of the case 13.

In this state, the gas supply device 21 is operated by a control signal from the control device 22 to supply an inert gas such as argon gas or nitrogen gas into the recess 14 of the case 13 via the supply valve 19. Supply. By supplying the gas into the recess 14, the internal air is exhausted to the outside through the exhaust valve 20, and the interior of the recess 14 is gas-replaced to be in an unoxidized state. Then, after the gas is supplied for a predetermined time, the current generator 12 is activated by the control signal of the controller 22 to supply a high frequency current of a predetermined frequency between the lower electrode 4 and the upper electrode 5.

When a high-frequency current is supplied to the lower electrode 4 and the upper electrode 5, this current flows in the base metal 8 as a conductor,
The base metal 8 is electrically heated. At this time, the cooling liquid is circulated and supplied into the electrodes 4 and 5 at the same time when the electric current is supplied to the electrodes 4 and 5, so that the heat generation of the electrodes 4 and 5 is suppressed. Also, the upper electrode 5
The peripheral portion of the shaft hole 9 of the base metal 8 where the concave portion 10 is located and the outer peripheral portion of the base metal 8 where the electrodes 4 and 5 are not located are not energized, and direct heating of these parts is suppressed. In particular, since the step portions 8a of the base metal 8 are stacked while being shifted in the circumferential direction and the vertical conduction is cut off, it is possible to prevent the step portion 8a from being energized and to prevent the portion from being overheated. it can.

Then, when the base metal 8 is electrically heated while being pressurized in a non-oxidized state for a predetermined time, the supply of the high frequency current to the lower electrode 4 and the upper electrode 5 is stopped, and the case body 13 is stopped.
Then, a and 13b are moved and the upper electrode 5 is raised, and thereafter, the cooling liquid is rapidly ejected from the cooling device (not shown) to cool the base metal 8 and the quenching process is completed. In this embodiment, the case moving device 15 is used to move the case bodies 13a and 13b in both directions. However, for example, one joint is used as a fulcrum, and the case body 13 is moved.
The case 13 may be opened by rotating a and 13b.

As described above, in the above quenching method,
Since a plurality of base metals 8 are set between the electrodes 4 and 5 and the base metal 8 is energized while being pressurized to perform induction hardening, quenching distortion of the base metal 8 can be minimized. In particular, since the electricity is applied in the non-oxidized state, the electricity can be uniformly applied over the entire area of the base metal 8, the quenching strain can be effectively suppressed, and the generation of scale or the like can be prevented.

Since both electrodes 4 and 5 are formed to have a smaller diameter than the base metal 8 and the recess 10 is provided in a portion corresponding to the shaft hole 9 of the upper electrode 5, the peripheral portion of the base metal 8 around the shaft hole 9 is formed. In addition to being able to prevent heating, since the stepped portion 8a of the base metal 8 is shifted and stacked, the heating of the outer peripheral portion of the base metal 8 is also prevented. From these, the part where the buckling phenomenon is likely to occur, that is,
It is possible to effectively quench the annular portion diametrically separated from the center of the base metal 8 by a predetermined distance.

Further, since a plurality of base metals 8 can be stacked and collectively processed, the quenching capacity can be improved. Further, a large electric furnace or the like is not necessary, the amount of the inert gas used can be reduced, and the quenching apparatus 1 can be easily maintained. As a result, the cost of the product can be reduced.

FIG. 4 is a schematic diagram showing another embodiment of the quenching apparatus according to the present invention. The characteristic of the quenching device 31 in this embodiment is that the base metal 8 for the lower electrode 32 and the upper electrode 33 is used.
The grooves 34 and 35 are formed on the contact surface with and. That is, the grooves 34 and 35 formed on the contact surfaces of the lower electrode 32 and the upper electrode 33 with the base metal 8 are formed in, for example, a spiral shape, and one end side thereof is a supply valve provided on the side surface of each of the electrodes 32 and 33. Three
6, 37, and the other end side communicates with recesses 38, 39 provided in the central portions of the electrodes 32, 33. The lower electrode 32 is formed with a discharge hole 40 that communicates the recess 38 with the outside. A discharge valve 41 is disposed in the discharge hole 40, and the supply valves 36 and 37 are connected to the gas supply device 21. Each is connected. Since the other configurations are the same as those in FIG. 1, the same reference numerals are given and detailed description thereof is omitted.

In the quenching apparatus 31 of this embodiment, the electrode moving means 7 is operated to lower the upper electrode 33, and the lower electrode 32.
By sandwiching the base metal 8 between the upper electrode 33 and the upper electrode 33, the groove 3
4 and 35 are sealed, and an inert gas is supplied into the grooves 34 and 35 from the gas supply device 21 via the supply valves 36 and 37. By the gas supply, the air in the groove 34 is exhausted to the outside via the recess 38 → the exhaust hole 40 → the exhaust valve 41, and the air in the groove 35 is recess 39 → the shaft hole 9 → the recess 38 →
It is discharged to the outside through the discharge hole 40 and the discharge valve 41. As a result, the insides of the grooves 34 and 35 are in a non-oxidized state, and in this state, the current generator 12 is operated and the base metal 8 is energized and heated to be quenched, as in the above embodiment.

Also in this embodiment, in addition to the same effects as the above-mentioned embodiment, the energization of the portions corresponding to the grooves 34, 35 is suppressed, so that the base metal 8 is formed by the shapes of the grooves 34, 35. It is possible to heat only a necessary portion of the above, and quenching strain can be further reduced. Further, the case 13, the case moving device 15, etc. are not required, and the structure of the quenching device 31 can be simplified. In addition, in this embodiment, the grooves 34 and 35 are not limited to the spiral shape, and may have, for example, a plurality of annular grooves and a groove for communicating the grooves.

FIG. 5 is a schematic configuration diagram showing still another embodiment of the quenching apparatus according to the present invention. The same parts as those in FIG. 1 will be described with the same reference numerals. The quenching device 51 of this embodiment is characterized in that the case 52, the lower electrode 53, and the upper electrode 54 are integrated. That is, the case 52 is divided into two case bodies 52a and 52b.
The lower electrode 53 and the upper electrode 54 are fixed inside a and 52b, respectively. At the joint of the case bodies 52a and 52b,
The step portion 55 is formed similarly to the case 13.

The case body 52b is connected to the electrode moving device 7
The case body 52a is provided with a supply valve 56 and a discharge valve 57, and the supply valve 56 is connected to the gas supply device 21. The heights of the lower electrode 53 and the upper electrode 54, and the heights (depths) of the case bodies 52a and 52b are the same when the step 55 of the case body 52b is brought into contact with the step 55 of the case 52a. A predetermined number of base metal 8 between the electrodes 53 and 54
Is set so as to be clamped with a predetermined pressure.

In the quenching method of this quenching device 51, first, the electrode moving device 7 is actuated by the control signal of the control device 22 to raise the case body 52b together with the upper electrode 54 so that the case body 52a is placed inside the case body 52a. , A plurality of base metals 8 are set in the same manner as in the above embodiment. Then, the case body 52b is lowered to bring the step portion 55 into contact with the step portion 55 of the case body 52a. As a result, the base metal 8 is pressurized with a predetermined pressure, and the base metal 8 is covered with the case 52 to be in a substantially sealed state.

In this state, gas is supplied from the gas supply device 21 into the case 52 to replace the gas inside the case 52.
A high-frequency current is supplied between 3 and 54 to electrically heat the base metal 8 as in the above embodiment. In this embodiment, the base metal 8 can be set only by moving the case body 52b up and down, which facilitates the work and eliminates the need for the case moving device 15 and the like of the quenching device 51. The configuration can be simplified.

In this embodiment, the case body 5
The supply valve 56 is arranged on the side surface of 2a to supply the gas into the case 52. For example, as shown by the chain double-dashed line in FIG.
Supply holes 58 are formed in the central portion of the lower electrode 53 and the bottom surface of the case body 52a, and a supply valve 59 is provided through the supply holes 58.
The gas may be supplied into the shaft hole 9 of the base metal 8 via the supply valve 5, or the gas may be supplied to both the side surface and the bottom surface of the case body 52a.
Gas may be supplied by arranging 6, 59 respectively.

Further, in each of the above-mentioned embodiments, an example of energization induction hardening in which the base metal is directly energized has been described, but the present invention is not limited to this. For example, the base metal of the lower electrode and the upper electrode may be used. It is also possible to fix the insulating sheet to the contact surface and to connect both electrodes with a conductive plate (not shown) to induce an induced current in the base metal for quenching. Further, in the above embodiment, the case has a circular outer shape, but may have a rectangular shape, for example, and the configuration of the electrodes and the case, a method of moving the case, and the like are various within a range not departing from the gist of the present invention. It goes without saying that it can be changed.

[0035]

As described above in detail, in the method and apparatus for quenching a circular saw tip saw base metal according to the present invention, the base metal is heated under pressure in an unoxidized state while being pressurized. It is possible to minimize the quenching distortion of, and to obtain a base metal with a good level of strength. In addition, a plurality of base metals can be collectively processed, and the quenching processing capability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a quenching device for a circular saw tip saw base metal according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged view of part B of FIG.

FIG. 4 is a schematic configuration diagram showing another embodiment of the quenching apparatus according to the present invention.

FIG. 5 is a schematic configuration diagram showing still another embodiment of the quenching apparatus according to the present invention.

[Explanation of symbols]

 1, 31, 51 Quenching device 4, 32, 53 Lower electrode 5, 33, 54 Upper electrode 7 Electrode moving device 8 Base metal 8a Step 9 Shaft hole 10, 38, 39 Recess 12 Current generator 13, 52 Case 13a , 13b, 52a, 52b Case body 14 Recessed portion 15 Case movement device 21 Gas supply device 22 Control device

Claims (7)

[Claims] 1. A plurality of base metals are stacked, and disc-shaped electrodes having an outer diameter smaller than the outer diameter of the base metal are brought into contact with the upper and lower surfaces thereof while applying pressure, and then the outer peripheral portion of the base metal is removed. A method for quenching a circular saw tip saw base metal, characterized by covering the case with a substantially sealed state, supplying an inert gas into the case, and then supplying a high-frequency current to the electrodes to quench the base metal. . 2. A disc-shaped electrode having an outer diameter smaller than that of the base metal and having a groove formed on the contact surface with the base metal is brought into contact with the upper and lower surfaces of the base metal while applying pressure. After that, an inert gas is supplied into the groove, and then a high-frequency current is supplied to the electrodes to quench the base metal, thereby quenching the circular saw tip saw base metal. 3. The circular saw tip saw stand according to claim 1, wherein the bases are stacked so that the chip mounting portions provided on the outer periphery thereof do not overlap each other. How to quench gold. 4. A pair of disc-shaped electrodes which sandwich the base metal at a predetermined pressure and which have an outer diameter smaller than the outer diameter of the base metal.
Electrode moving means for moving at least one of the electrodes up and down, and a case provided in a case that covers a portion of the base metal projecting from the electrode side surface in a substantially sealed state, or a groove provided in a contact surface of the base metal with the base metal. Gas supply means for supplying an inert gas to the, and current supply means for supplying a high-frequency current to the electrode,
A quenching device for a circular saw tip saw base metal, comprising: 5. The portion of the electrode corresponding to the shaft hole of the base metal,
The quenching device for a circular saw tip saw base metal according to claim 4, wherein a recess is formed. 6. The quenching device for a circular saw tip saw base metal according to claim 4, wherein the groove is formed in a spiral shape. 7. The quenching device for a circular saw tip saw base metal according to claim 4, wherein the electrode is provided integrally with the case.