KR200401078Y1 - Work-Coil For A Heat Treatment With High Frequency - Google Patents

Abstract

The present invention is a high-frequency heat treatment for the high-frequency heat treatment for the workpiece in the form of a pipe, while simultaneously performing a heating process and a quenching process at the same time, to perform a rapid cooling process at the inside and the outside of the workpiece, It relates to a work coil.

Description

Work-Coil For A Heat Treatment With High Frequency

The present invention relates to a work coil for high frequency heat treatment for heat treatment of a workpiece, and particularly to a high frequency heat treatment apparatus for conducting surface hardening by induction heating of a pipe-shaped workpiece having a conductive, elongated shape and having a perforated interior. It relates to the work coil used.

First, the general content of the high frequency heat treatment will be briefly described as follows.

The purpose of the high frequency heat treatment in the surface hardening treatment is to cure the surface of the workpiece, to improve the wear resistance and to improve the mechanical properties of the workpiece. In other words, the high frequency heat treatment uses a high frequency induction heating method to rapidly heat the surface of the workpiece at a quenching temperature (typically about 900 ° C.), and then rapidly cools the surface of the workpiece with cooling water. This is a method of obtaining a hardened hardened layer.

In other words, the high frequency heat treatment allows the surface of the workpiece to be quenched by rapidly heating only the surface of the workpiece due to the high frequency skin effect. Heating takes place. Therefore, when quenching to a certain depth is required, the high frequency induction heating apparatus may be adjusted and used as follows.

First, short time heating at low frequency, high power density

Second, long time heating at high frequency, low power density

On the other hand, high frequency heat treatment can be used for a relatively wide range of applications by adjusting the heating time and power density even if the frequency is determined as described above.

At this time, the hardening depth of the high frequency quenching is changed by three kinds of frequency, power density (high frequency power kW per 1 cm 2 of heating surface area) and heating time. Frequently, the frequency is generally used between 10 kHz and 3 MHz, and the frequency around 50 kHz to 400 kHz is used very much.

In addition, induction heating has an excellent advantage compared to the hardening method according to the metal surface. That is, the quenched layer becomes precise martensite by a short time heating, and the hardness decreases rapidly as it goes to the center with a uniform hardness throughout the cured layer to become a known hardness. In addition, rapid heating can eliminate the post-treatment process by reducing the occurrence of scale and torsion.

On the other hand, the heating coil should be designed to be coupled as close as possible to the object to be heated in order to transfer the maximum energy to the object to be heated so that many magnetic lines of force cross. This is because the higher the magnetic flux density, the more current is induced in the load.

The magnetic flux is concentrated close to the heating coil and decreases as it moves away, and the magnetic flux is weak at the center of the heating coil. Therefore, when the workpiece moves away from the center of the heating coil, more magnetic lines intersect on the surface adjacent to the heating coil and the heating speed becomes faster, and the opposite side is heated at a slower speed due to the lack of bonding, thereby rotating the workpiece. Let's go.

Next, a conventional high frequency heat treatment work coil will be described with reference to FIG. 1 as follows. At this time, the conventional high-frequency heat treatment work coil shown in Figure 1, filed by the applicant of December 27, 2000, the name of the invention [high frequency heat treatment work coil] (application number: 20-2000-0036656) As described in the specification, detailed description thereof will be omitted.

1 is an exemplary view of a conventional high frequency heat treatment apparatus.

That is, FIG. 1 is a conventional high frequency heat treatment work coil for heating and cooling a workpiece, and an inflow terminal into which a high frequency current supplied from an oscillator flows and one side end of a coil part are connected to each other. In the work coil for high frequency heat treatment in which the high-frequency current flowing through the outlet terminal and the other end of the coil portion is connected to each other, and an insulating material is interposed between the inflow terminal and the outlet terminal, An inlet port through which the coolant supplied from the coolant supply device flows and one end of the coil unit are connected to each other, and an outlet port through which the coolant introduced through the inlet port flows out to the coolant supply device and the other side of the coil unit. The ends are connected to each other, and the downstream side of the coil part with respect to the workpiece To carry out the cold, there is shown a high-frequency heat treatment for the work coil for being formed into a number of separate additional cooling of the hollow fiber with a cooling water outlet at all. In this case, the work coil for high frequency heat treatment as shown in FIG. 1 is for heat treating a workpiece having a hollow rod shape, and one side of the coil part is configured to be open.

Meanwhile, not only rod-shaped workpieces but also pipe-shaped workpieces require high frequency heat treatment. In the case of workpieces such as oil drilling pipes, heat treatment is required to withstand high heat and high wear. However, there is a problem in that the work coil of the type as shown in FIG. 1 cannot perform an appropriate high frequency heat treatment on the workpiece in the form of a pipe.

That is, the work coil for high frequency heat treatment shown in FIG. 1 is open at one side of the coil part, and thus the front surface of the workpiece in the form of a pipe cannot be heated evenly, and only the outside of the workpiece can be cooled, but the inside of the workpiece is cooled. There is a problem that it is not possible to perform a uniform heat treatment for the workpiece.

In addition, the heating and cooling time for the workpiece in the form of pipes occupy an important factor in the heat treatment, but the work coil for high frequency heat treatment as shown in FIG. There is a problem that can not be maintained.

An object of the present invention for solving the above problems, while simultaneously performing a heating process and a quenching process at the same time, during the high frequency heat treatment operation on the workpiece in the form of a pipe, the quenching process at the same time inside and outside the workpiece In order to be able to perform, to provide a work coil for high frequency heat treatment.

The present invention for achieving the above object, in the work coil for high frequency heat treatment applied to the high frequency heat treatment apparatus, the electrode portion 10 composed of the first electrode portion and the second electrode portion connected to each of the two terminals of the high frequency oscillator ; It is composed of a circular coil so that the workpiece in the form of a pipe can pass, and two terminals (first terminal and second terminal) forming the circular coil are connected to the first electrode portion and the second electrode portion to A coil unit 20 for heating the workpiece by receiving a high frequency from a high frequency oscillator; Located in one side of the circular coil to perform quenching on the outside of the workpiece after being heated by the coil portion and passed through the circular coil, a circular for ejecting the cooling water through a plurality of second cooling water jet holes Outer cooling unit 30; A connection part 40 for connecting and fixing the circular coil of the coil part and the outer cooling part; And a plurality of third cooling water positioned on the same plane with the same central axis as the outer cooling portion to perform quenching on the inside of the workpiece that has been heated by the coil portion and then passed through the circular coil. A circular inner cooling portion 50 having a length smaller than the radius of the outer cooling portion for ejecting the cooling water through the jet port.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a perspective view of one embodiment of a work coil for high frequency heat treatment according to the present invention, Figure 3 is a front view of an embodiment of a work coil for high frequency heat treatment according to the present invention, Figure 4 is a work coil for high frequency heat treatment according to the present invention One embodiment of the left side view.

As shown in the drawings, the work coil for high frequency heat treatment according to the present invention heats a workpiece in the form of a pipe (hereinafter, simply referred to as a 'workpiece') using a high frequency while cooling the inside and the outside of the workpiece. A work coil for high frequency heat treatment for performing a treatment, comprising: an electrode portion 10 composed of a first electrode portion and a second electrode portion connected to two terminals of a high frequency oscillator, and a plurality of circular coils to allow a workpiece to pass therethrough And two terminals (first terminal and second terminal) forming the plurality of circular coils are connected to the first electrode portion and the second electrode portion to receive a high frequency from the high frequency oscillator. Coil section 20 for heating, for performing quenching on the outside of the workpiece after being heated by the coil section and passed through the plurality of circular coils A circular outer cooling part 30 positioned at one side of the circular coil and having a plurality of second cooling water jet holes, at least two connection parts 40 for connecting the circular coil and the outer cooling part of the coil part; Inner cooling with a plurality of third cooling water outlets for quenching the inside of the workpiece as a circular shape having a length smaller than the radius of the outer cooling portion with the same central axis as the outer cooling portion The part 50 is included.

First, in order to heat the workpiece 90 by using a high frequency, the coil part 20 includes a first electrode part 11 and a first electrode part into which a high frequency current supplied from a high frequency oscillator, not shown, is introduced. The terminals 21 are connected to each other, and the second electrode portion 12 and the second terminal 22 through which the high frequency current flowing through the first electrode portion 11 flows out to the high frequency oscillator are connected to each other. have. In this case, an insulating material 60 is inserted between the first electrode part 11 and the second electrode part 12, so that current flows between the first electrode part 11 and the second electrode part 12. Is to proceed only through the coil unit 20.

On the other hand, an example of the frequency and capacitance of the high frequency oscillator is shown in Table 1 below.

In this case, the coil unit 20 is overheated in the work coil for high frequency heat treatment due to the heat treatment of the workpiece 90. In order to prevent this, the first cooling water inflow port 23 through which the coolant supplied from the cooling water supply device not shown is introduced is connected to the first terminal 21 and the first cooling water inflow port 23 The first coolant outlet port 24 through which the coolant flowing through the outlet is discharged to the coolant supply device is connected to the second terminal 22, and the inside of the entire section of the coil unit 20 is empty. . Therefore, the cooling water introduced through the first cooling water inflow port 23 passes through the plurality of circular coils 26 through the first terminal 21 and then the second terminal 22 and the first cooling water outlet port. Through 24 it flows out to the cooling water supply.

In addition, the plane formed by the plurality of circular coils 26 is oriented at an angle perpendicular to the central axis of the outer cooling unit 30 or the inner cooling unit 50, as shown in the drawing. The circular coil 26 has a feature that the workpiece 90 can be heated in a uniform direction. In other words, if the circular coil 26 is oriented in a direction oblique to the central axis, heat by the circular coil 26 will be applied to the workpiece 90 in an oblique direction, which causes uniform heating of the workpiece. It can also act as a factor to hinder, resulting in halving the effect of the heat treatment itself.

Next, at one side of the plurality of circular coils 26, a hollow outer cooling unit 30 for quenching the outer side of the workpiece 90 is located, the outer cooling unit 30 The outer side cooling coil 33 of) and the circular coil 26 of the coil part 20 are integrally connected by the connection part 40 as mentioned above. At this time, the outer cooling coil 33, the second cooling water inlet port 31 through which the cooling water supplied from the cooling water supply device flows and the cooling water introduced through the second cooling water inlet port toward the workpiece. A plurality of second cooling water jet holes 32 are formed to be jetted.

Therefore, the coolant flows into the outer cooling coil 33 through the second cooling water inlet port 31 from the cooling water supply device, and then is discharged to the outside through the second cooling water jet port 32, so that the circular coil 26 The outside of the workpiece 90 penetrating through the circular interior of the will be cooled. In this case, when only one second cooling water inflow port 31 is formed, the inflow pressure of the cooling water decreases, so that the ejection pressure of the cooling water ejected through the plurality of second cooling water ejection ports 32 is uneven. As a result, the degree of cooling the workpiece 90 becomes non-uniform, so that the present invention, at least two or more second cooling water inlet ports 31 are preferably formed, to prevent this, in one embodiment of the present invention As an example, FIG. 2 shows an outer cooling coil 33 in which three second cooling water inlet ports 31 are formed.

That is, in the work coil for high frequency heat treatment according to the present invention, the coolant passing through a path different from the coolant flowing into the coil part 20 is passed through the second cooling water inlet port 31 to the outer cooling coil 33. Into the inside of the, it is ejected through the plurality of second cooling water jet holes 32, the rapid cooling to the desired temperature for the workpiece heated through the plurality of circular coils 26 of the coil unit 20 can do.

Next, the circular coil 26 of the coil part 20 and the outer cooling coil 33 of the outer cooling part 30 are fixed at regular intervals by at least two or more connection parts 40 as described above. . At this time, the connection portion 40, a plurality of connection holes 41, which can be inserted into the protruding terminals 25, 34 protruding on the surface of the circular coil 26 or the outer cooling coil 33 is connected to the connection bar ( The protrusions 25 and 34 inserted into the connection holes 41 are fixed to the connection bars 43 by the connection screws 42 at predetermined intervals. That is, the interval between the circular coil 26 of the coil unit 20 and the outer cooling coil 33 of the outer cooling unit 30 is in order to perform the optimal heat treatment for the workpiece 90, the workpiece It is necessary to be adjusted according to the thickness and radius of the 90, so that the user calculates an appropriate interval in consideration of the thickness and radius of the workpiece 90, the connection terminal 25, 34 to the connection The heat treatment may be performed after insertion at an appropriate position of the connecting hole 41 of the bar 43.

In this case, various examples regarding the distance between the circular coil 26 and the outer cooling coil 33 according to the thickness and diameter of the workpiece are shown in Table 2 below.

That is, the types of workpieces that can be applied to the present invention are various, and the distance between the circular coil 26 and the outer cooling coil 33 depends on the thickness and diameter of the workpiece. The gap of the hole 41 can be adjusted. On the other hand, the high-frequency heat treatment work on the workpiece can be greatly affected by the quality, depending on the frequency and capacitance of the high-frequency oscillator, the user can refer to the data shown in Table 1 above.

Finally, the present invention includes an inner cooling unit 50 having the same central axis as the outer cooling coil 33 and consisting of a hollow inner cooling coil 53 positioned on the same plane. At this time, the inner cooling coil 53, the third cooling water inlet port 51 through which the coolant supplied from the cooling water supply device flows and the cooling water introduced through the third cooling water inlet port toward the workpiece. A plurality of third cooling water jet holes 52 are formed to be jetted.

Therefore, the coolant flows into the inner cooling coil 53 through the third cooling water inlet port 51 from the cooling water supply device, and then is discharged to the outside through the third cooling water jet port to form a circular shape of the inner cooling coil 530. The inside of the workpiece penetrating the outside is cooled.

That is, the work coil for high frequency heat treatment according to the present invention heats the workpiece having a hollow pipe shape through a plurality of circular coils 26, and is located at the same center with a predetermined distance from the circular coils. The outer cooling coil 33 and the inner cooling coil 53 on the axial and planar surfaces can be cooled at the same time.

Summarizing the features of the present invention as described above are as follows.

That is, the present invention relates to a work coil used for a high frequency heat treatment operation for enabling the foreground of a long axis drilling pipe (workpiece) by high frequency induction hardening. It is important to heat the workpiece from the outside to raise the temperature uniformly to the quenching temperature from the outside to ensure that the workpiece has a uniform hardness after cooling. At this time, the main variables are the material, thickness, diameter, frequency, capacitance, circular coil 26, cooling method, and the like, as described above.

On the other hand, since the smaller the spacing between the workpiece and the circular coil 26, the better the efficiency, the circular coil 26 should have a distance between the pipe outer diameter and the circular coil 26 at least about 5 mm depending on the diameter of the workpiece. As shown in Table 2, more is possible.

In addition, as the distance between the inner cooling coil 53 and the inner diameter surface of the pipe (workpiece) is also closer, cooling can be performed faster. At this time, the internal and external injection cooling angle (that is, the cooling water jet angles of the cooling water jet holes 32 and 52) may be about 60 °. On the other hand, more important than the injection angle is that the injection positions of the inner and outer cooling coils 33 and 53 should be the same according to the thickness of the workpiece, which is an important parameter in obtaining a uniform hardness value of the workpiece. Hardening hardness values vary from material to material and in the case of drilling pipes HRC40 to 45 are obtained. The hardness spec of general drilling pipe is about HRC 30 ± 2, and in order to have this hardness value, it is necessary to be tempered occasionally.

In addition, in order to have a uniform hardness value according to the thickness of the pipe (workpiece), the circular coil 26 is a circular multi-stage (about three stages) coil which can heat a wider range than the circular single coil wound once. Should be used. In this case, as the frequency of the high frequency oscillator is changed, the number of windings of the circular coil may be changed.

In addition, a certain time is required in order for the workpiece to be started with high frequency induction heating through a plurality of external circular coils 26 and heated to a uniform quenching temperature to the inside, and the present invention directly cools the workpiece. Instead, the cooling coils 33 and 53 are adjusted in position to allow delay cooling. That is, the present invention was to enable the position adjustment of the cooling coils 33 and 53 so that the cooling water is injected at a position where the internal and external temperatures are uniform according to the thickness of the workpiece, and the inner cooling coil 53 inside the workpiece. Was placed at the same position as the outer cooling coil 33 so that the outside and the inside were cooled at the same time.

Referring to the above, the method of use of the present invention will be described briefly as follows.

First, the user places the workpiece 90 on the same central axis as the central axis of the plurality of circular coils 26. At this time, although not shown in the figure, the workpiece 90, in the horizontal direction on the height adjustable guidelane so that the center axis of the workpiece on the same central axis as the circular coil 26 can be located It may be placed, or may be placed in a vertical direction using a separate tong device.

Thereafter, the user inserts the inner cooling unit 50 into the workpiece 90 to adjust the outer cooling coil 33 and the inner cooling coil 53 to be coplanar and coaxial. The third cooling water inlet port 51 is fixed to the cooling water supply device.

After the above setting is completed, the user drives the guide lane or tongs device, while driving the high frequency oscillator to heat the plurality of circular coils 26, and the coolant supply device to drive the outer cooling coil. Cooling water is supplied to the 53 and the inner cooling coil 53.

Thus, the workpiece 90 is inserted into the circumference of the plurality of circular coils 26 or on the guide lane or through a forceps device, and the heated portion is again spaced apart from the outer cooling coil 33 by a distance. It is cooled by the cooling water jetted from the outer cooling coil 33 and the inner cooling coil 53 while passing through the inner circumference of the inner and inner circumference of the inner cooling coil 53 of.

On the other hand, in the heat treatment of the drilling pipe (workpiece) of the long axis as described above, when the heat treatment while rotating the pipe (workpiece), the deformation can be minimized.

The present invention is not limited to the embodiments described above, it can be various modifications and changes by those skilled in the art, which is included in the spirit and scope of the present invention defined in the appended claims.

The present invention configured as described above enables the user to perform the quenching process essential for high frequency surface heat treatment of a workpiece such as a pipe according to the characteristics of each workpiece, thereby improving the productivity of the workpiece and increasing the manufacturing cost. It has an excellent effect of lowering.

That is, the present invention allows the user to adjust the injection position of the cooling water, thereby uniformly reaching the heat treatment temperature according to the thickness of the pipe (workpiece), and by performing external cooling and internal cooling at the same time the entire pipe (workpiece) Has an excellent effect of having a constant hardness value.

1 is an exemplary view of a conventional high frequency heat treatment apparatus.

Figure 2 is a perspective view of one embodiment of a work coil for high frequency heat treatment according to the present invention.

3 is a front view of an embodiment of a work coil for high frequency heat treatment according to the present invention;

Figure 4 is a left side view of an embodiment of a work coil for high frequency heat treatment according to the present invention.

Claims (4)

In the work coil for high frequency heat treatment applied to the high frequency heat treatment apparatus, An electrode portion 10 composed of a first electrode portion and a second electrode portion respectively connected to two terminals of the high frequency oscillator; It is composed of a circular coil so that the workpiece in the form of a pipe can pass, and two terminals (first terminal and second terminal) forming the circular coil are connected to the first electrode portion and the second electrode portion to A coil unit 20 for heating the workpiece by receiving a high frequency from a high frequency oscillator; Located in one side of the circular coil to perform quenching on the outside of the workpiece after being heated by the coil portion and passed through the circular coil, a circular for ejecting the cooling water through a plurality of second cooling water jet holes Outer cooling unit 30; A connection part 40 for connecting and fixing the circular coil of the coil part and the outer cooling part; And A plurality of third cooling water jet holes positioned on the same plane with the same central axis as the outer cooling part to perform quenching on the inside of the workpiece that has been heated by the coil part and then passed through the circular coil; Circular inner cooling portion 50 having a length smaller than the radius of the outer cooling portion for ejecting the cooling water through the Work coil for high frequency heat treatment comprising a. The method of claim 1, The coil unit 20, A first terminal 21 connected to the first cooling water inflow port through which the cooling water supplied from the cooling water supply device flows; A second terminal 22 connected to the first cooling water outlet port through which the coolant flowing through the first cooling water inflow port flows out to the cooling water supply device; And A circular coil 26 wound around the first terminal and the second terminal in the form of a circular coil, The first terminal, the second terminal and the circular coil has a hollow hollow shape so that the cooling water flows High-frequency heat treatment work coil, characterized in that. The method of claim 1, The connecting portion 40, A connection bar 43 in which a plurality of connection holes 41 into which the protruding terminals 25 and 34 protruding from the surface of the circular coil or the outer cooling unit can be inserted are formed at regular intervals; And Connection screw 42 for fixing the protruding terminals 25 and 34 inserted into the connection hole 41 to the connection bar. Work coil for high frequency heat treatment comprising a. The method of claim 1, The inner cooling unit 50, A hollow inner cooling coil 53 positioned on the same plane as the outer axis of the outer cooling unit and having a third cooling water jet port 52 for ejecting the cooling water in a direction toward the workpiece; And One side is connected to the cooling water supply device, the other side is connected to the inner cooling coil 53, the third cooling water inlet port 51 for introducing the cooling water supplied from the cooling water supply device into the inner cooling coil; Work coil for high frequency heat treatment comprising a.