KR101230091B1 - Batch annealing furnace and method of annealing coil using the same - Google Patents

Abstract

PURPOSE: A batch annealing furnace and a coil annealing method using the same are provided to improve the quality of a coil because the inner and outer materials of the coil are not changed according to the annealing temperature difference of the inside and outside of the coil. CONSTITUTION: A batch annealing furnace(100) comprises a chamber(5), a main heater(20), and an auxiliary heater(80). The main heater is mounted in the chamber to generate heat. The auxiliary heater is separated from a wall of the chamber and generates heat. The auxiliary heater comprises a supporter(60), heating members(70), and a heat circulating part(50).

Description

Batch ANNEALING FURNACE AND METHOD OF ANNEALING COIL USING THE SAME}

The present invention relates to a batch annealing furnace, and more particularly, to uniformly heat the inside and the outside of the wound coil, to minimize the variation of the material properties of the outside and the inside of the final annealed coil to improve the quality of the coil It relates to a batch annealing furnace and a method of annealing the coil using the same.

The batch annealing furnace is a device in which a coil wound up is placed therein and the coil is annealed. The batch annealing furnace includes a chamber in which an inert gas atmosphere or a vacuum atmosphere can be formed.

In general, when annealing the coil in a vacuum atmosphere, the coil is annealed by radiant heat because there is no medium for transferring heat generated from the heating apparatus of the batch annealing furnace. Further, in general, in the batch annealing furnace, since the heating device is disposed on the wall side of the chamber, more radiant heat is transmitted to the outer side of the coil than the inner side of the coil, so that the heat treatment effect due to the annealing between the inner and outer sides of the coil is improved. The quality of the differently annealed coils may be degraded.

An object of the present invention, by heating the inside and the outside of the coil wound uniformly, by using a batch annealing furnace that can improve the quality of the coil by minimizing the variation of the material characteristics of the outside and inside of the final annealed coil The present invention provides a method of annealing a coil that can uniformly anneal the coil.

Batch annealing furnace for achieving the above object of the present invention, the chamber, the main heating device which is provided in the chamber to generate heat, and the heat generated in the chamber spaced apart from the wall of the chamber than the main heating device And an auxiliary heating device.

The auxiliary heating apparatus may further include a support extending from the bottom of the chamber in the height direction of the chamber, a heating member provided in the support, and at least one opening formed on the upper end of the support. Include.

In addition, the method of annealing the coil using a batch annealing furnace for achieving the above object of the present invention is as follows.

A coil is provided in the chamber of the batch annealing furnace, a vacuum atmosphere is created in the chamber, and the inner side of the coil is heated separately from the outer side of the coil to anneal the coil in the vacuum atmosphere.

After the first annealing is completed, the vacuum atmosphere in the chamber is released, an inert gas is provided in the chamber, after which the coil is heated to a second annealing.

According to the present invention, the auxiliary annealing device is provided in the batch annealing furnace so that the outside and the inside of the coil can be uniformly heated. Accordingly, when annealing the coil using the batch annealing furnace, it is possible to solve the problem that the material of the inside and the outside of the coil due to the difference in the annealing temperature of the outside and inside of the coil is improved, thereby improving the quality of the coil.

1 is a cross-sectional view of a batch annealing furnace according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view of the auxiliary heating device and coil illustrated in FIG. 1.
3 is a plan view of the auxiliary heating device shown in FIG.
4 is a flowchart illustrating a method of annealing a coil using the batch annealing furnace illustrated in FIG. 1.
5 is a cross-sectional view of a batch annealing furnace according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The objects, features and effects of the present invention described above will be readily understood through embodiments related to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be applied and modified in various forms. Rather, the following embodiments are provided so that the technical spirit disclosed by the present invention more clearly, and furthermore, the technical spirit of the present invention can be sufficiently delivered to those skilled in the art having ordinary knowledge in the field to which the present invention belongs. Therefore, the claims of the present invention should not be construed as limited by the embodiments described below. On the other hand, the drawings presented in conjunction with the following examples are somewhat simplified or exaggerated for clarity, the same reference numerals in the drawings represent the same components.

1 is a cross-sectional view of a batch annealing furnace according to an embodiment of the present invention.

Referring to FIG. 1, the batch annealing furnace 100 is an apparatus for annealing coils CL stacked in multiple stages therein. In an embodiment of the present invention, the batch annealing furnace 100 includes titanium and titanium alloys. Can be used to anneal the coil (CL). The structure of the batch annealing furnace 100 is as follows.

A fixed base 1 is provided below the batch annealing path 100, and a load plate 30 supporting the load of the coil CL is provided on the fixed base 1. The coil loading space is defined in multiple stages on the road plate 30, and the coil CL is loaded in the coil loading space. In addition, a convection plate 25 having a through hole is disposed between the coils CL to improve the flow of thermal convection.

The chamber 5 accommodates the coil CL therein, and a furnace cover 7 is installed outside the chamber 5. The main heating device 20 generates heat for annealing the coil CL, and the main heating device 20 is provided adjacent to the wall of the chamber 5 to form an inner side S1 of the coil CL. Rather, it is disposed closer to the outer side S2 of the coil CL.

In addition, a fan 10 driven by the rotary prime mover 11 is disposed under the load plate 30 so that the flow of heat convection in the chamber 5 is improved, and an upper portion of the furnace cover 7 is provided. Furnace communication (9) covering the is connected to the exhaust communication (not shown).

On the other hand, according to the embodiment of the present invention, the batch annealing furnace 100 includes an auxiliary heating device (80). The auxiliary heating device 80 includes a support 60, a heating member 70 and the heat circulation (50).

The support 60 faces the main heating device 20 with the multi-stage coils CL interposed therebetween, and the support 60 is in the height direction of the chamber 5, that is, the coils CL. It extends in this stacked direction and is spaced apart from the inner side S1 of the coil CL. In addition, the heat circulation part 50 has at least one opening penetrating the inside thereof, and is provided on the upper end of the support 60 to cover the coil CL loaded in the coil loading space. In addition, the heating member 70 is provided on the support 60 to generate heat for annealing the coil CL.

According to the configuration of the auxiliary heating device 80 described above, if the main heating device 20 is disposed closer to the outer side (S2) than the inner side (S1) of the coil (CL), the auxiliary heating device (80) The heating member 70 of) is disposed closer to the inner side S1 than to the outer side S2 of the coil CL.

On the other hand, when the inside of the chamber 5 is a vacuum atmosphere, heat generated from the main heating device 20 and the auxiliary heating device 80 is transmitted to the coil CL side in the form of radiant heat. Therefore, the radiant heat generated by the main heating device 20 can be easily transmitted to the outer side S2 than the inner side S1 of the coil CL, and the radiant heat generated from the auxiliary heating device 80 is It may be easily transferred to the inner side S1 rather than the outer side S2 of the coil CL.

The structure of the auxiliary heating device 80 described above will be described in more detail with reference to FIGS. 2 and 3 as follows.

FIG. 2 is an exploded perspective view of the auxiliary heating apparatus and coil illustrated in FIG. 1, and FIG. 3 is a plan view of the auxiliary heating apparatus illustrated in FIG. 1.

2 and 3, the support 60 of the auxiliary heating device 80 has a hollow shape. Accordingly, when annealing the coil CL using heat convection, the heat convection can pass through the interior of the support 60. In the embodiment of the present invention, in order to uniformly heat the inner side S1 of the coil CL, the support 60 may have a cylindrical shape. In this case, the support 60 is inserted into the coil CL wound in a roll shape, but the support 60 is spaced apart from the inner surface S1 of the coil CL. The diameter L1 of) may be set smaller than the inner diameter L3 of the coil CL. Accordingly, heat convection may pass between the support 60 and the inner side S1 of the coil CL. .

In addition, in the exemplary embodiment of the present invention, the diameter L1 of the support 60 may be set to 20% or more of the width length L2 on which the coil CL is wound. When the diameter L1 is set to less than 20% of the width length L2, a portion of the coil CL facing the position where the heating member 70 is not installed on the support 60 is The effect of annealing can be reduced.

The heating member 70 is provided on the outer circumferential surface of the support 60. In the embodiment of the present invention, in order to uniformly heat the inner side S1 of the coil CL, the heating member 70 may be installed along the outer circumferential surface of the round shape of the support 60. In addition, in the embodiment of the present invention, the heating member 70 may be provided in plural, and in this case, to correspond to the height of the coil CL loaded in three stages in the chamber (5 of FIG. 1) in one-to-one correspondence. The heating member 70 may be implemented as a first heating member 71, a second heating member 72, and a third heating member 73.

In addition, first to third thermocouple thermometers 76, 77, and 78 may be installed to correspond to the first to third heating members 71, 72, and 73 one to one, and the first to third thermocouples may be installed. Temperatures of heat generated from the first to third heating members 71, 72, and 73 are measured by the thermometers 76, 77, and 78.

On the other hand, the upper end of the support 60 is provided with a thermal cycle (50). The heat circulation part 50 has a vent hole 57 in which a part is removed in correspondence with the hollow position of the support 60. Therefore, the heat convection moving along the inside of the support 60 may be discharged to the outside of the auxiliary heating device 80 through the ventilation hole 57.

In addition, the thermocycling unit 50 has a plate shape having a circular border on a plane, and a plurality of openings 51 are formed in the thermocycling unit 50. Therefore, heat convection flowing in the chamber (5 of FIG. 1) is provided to the coil CL located under the heat circulation part 50 through the openings 51 to anneal the coil CL. Can be improved.

On the other hand, when the chamber (5 in FIG. 1) of the batch annealing furnace (100 in FIG. 1) is in a vacuum atmosphere, since no medium transfers heat in the chamber, heat is transferred to the coil CL in the form of radiant heat. The coil CL is annealed. Therefore, in general, when the heating apparatus of the batch annealing furnace is installed only on the wall side of the chamber, more radiant heat is provided to the outer side (S2) than the inner side (S1) of the coil (CL). Similarly, in the case of installing an auxiliary heating device 80 having a heating member 70 inside the chamber at the same time as installing the main heating device (20 in FIG. 1) adjacent to the wall of the chamber, the coil CL Radiation heat may be uniformly transmitted to the inner side (S1) and the outer side (S2) of. Therefore, the deviation of the temperature at which the inner side S1 and the outer side S2 of the coil CL are annealed is reduced, so that the size of the crystal grains of the coil CL as a whole can be uniform without distinguishing the inner side S1 and the outer side S2. In addition, the variation in yield strength difference between the inner side S1 and the outer side S2 is reduced, so that the quality of the coil CL can be improved.

In addition, even when an inert gas is provided to the chamber to anneal the coil CL by thermal convection, it is generated by heat generated from the heating member 70 of the main heating device and the auxiliary heating device 80. The heat convection thus obtained can uniformly anneal the inner side S1 and the outer side S2 of the coil CL.

4 is a flowchart illustrating a method of annealing a coil using the batch annealing furnace illustrated in FIG. 1.

The method of annealing the coil by using the batch annealing furnace according to the present invention with reference to FIGS. 1 and 4 is as follows.

First, the coil CL is charged into the chamber 5 of the batch annealing furnace 100 (S10), and thereafter, the inside of the chamber 5 is formed in a vacuum atmosphere (S20). In the embodiment of the present invention, the internal pressure of the chamber 5 may be set to approximately 1ⅹ10 ^-4 Torr or less.

Subsequently, the inner side S1 and the outer side S2 of the coil CL are heated by using the heating member 70 of the main heating device 20 and the auxiliary heating device 80, and then, the vacuum atmosphere is radiated. The coil CL is first annealed (S30). Since the first annealing proceeds in a vacuum atmosphere, heat is provided to the coil CL in the form of radiant heat, and the coil CL is annealed. Accordingly, radiant heat generated from the main heating device 20 is mainly provided to the outer side S2 of the coil CL, and radiant heat generated from the heating member 70 is mainly inner side S1 of the coil CL. The inner side S1 and the outer side S2 of the coil CL may be uniformly heated.

Meanwhile, the first annealing may be performed for the purpose of vaporizing and removing impurities remaining on the surface of the coil CL. In an embodiment of the present invention, in the first annealing step, the coil CL may be annealed to about 500 ° C. or less, which is a temperature at which recrystallization of the coil CL is about 150 ° C. or more. In addition, the first annealing step may be performed for about 3 hours to about 6 hours, because the annealing temperature may not be reached when the annealing time is less than 3 hours, and generally the coil CL This is because impurities in the coil CL can be almost removed in the case of annealing for 6 hours.

After the first annealing is completed, the vacuum atmosphere in the chamber 5 is released (S40), and the pressure in the chamber 5 is maintained at about 700 Torr to about 760 Torr. When the pressure in the chamber 5 is less than 700 Torr, the atmosphere outside the chamber 5 may flow into the chamber 5 to cause oxidation of the coil CL, and the pressure in the chamber 5 is 760 Torr. In the case of exceeding the pressure inside the chamber 5 is higher than the outside may cause a safety accident.

Thereafter, an inert gas such as argon gas is provided in the chamber 5 (S50), and the inner side of the coil CL using the heating member 70 of the main heating device 20 and the auxiliary heating device 80. (S1) and the outer side (S2) are heated, and after the second annealing of the coil (CL) for a predetermined time using heat convection by an inert gas (S60), it is cooled to about 300 ℃ (S70).

Since the second annealing proceeds in an inert gas atmosphere, heat is provided to the coil CL side by thermal convection. In addition, similarly to the first annealing, the inner side S1 and the outer side of the coil CL by heat convection generated from the main heating device 20 and the heating member 70 also during the second annealing. S2 is uniformly heated to anneal the coil CL.

The above-described batch annealing furnace of the present invention and effects produced when annealing coils using the same will be described with reference to Table 1 below.

division Inside the coil
Temper color occurs Temper color outside coil Temperature difference between the inside and outside of the coil (℃) Grain size difference (micron) inside and outside the coil Yield strength difference (Mpa) inside and outside the coil Invention
Example Not occurring Not occurring 50 0.3 7 Comparative Example 1 Occur Not occurring 100 3 30 Comparative Example 2 Occur Occur 70 1.5 15

In the embodiment of the present invention of Table 1 above, the batch annealing furnace (100 of FIG. 1) described above with reference to FIGS. 1 to 4 and industrial pure titanium having a thickness of 0.5 mm and a width of 1219 mm using the same. (commercially pure titanium) shows the physical properties of the coil obtained by annealing the coil of the strip. In addition, in the embodiment of the present invention of Table 1, annealing the coil for 6 hours at 500 ℃ in the vacuum atmosphere during the first annealing, annealing for 10 hours at 650 ℃ in an inert gas atmosphere during the second annealing. .

In addition, in Comparative Example 1 of Table 1, a batch annealing furnace in which the auxiliary heating device (80 in FIG. 1) described above with reference to FIGS. 1 to 4 was used was used, and the coils and annealing used in the test were also used. The conditions are the same as in the embodiment of the present invention.

In addition, in Comparative Example 2 of Table 1, a batch annealing furnace in which the auxiliary heating device (80 of FIG. 1) described above with reference to FIGS. 1 to 4 was used was used, and the coil used in the test was a In the same manner as in Example, the first and the second annealing were respectively reduced in pressure within the chamber to 1 × 10 ^-4 Torr or less, and then, the argon gas was blown into the chamber at about 700 torr to anneal the coil.

As a result, in the embodiment of the present invention, the temper color was not generated inside and outside the coil, so that the overall surface quality of the coil was excellent, but in Comparative Example 1 and Comparative Example 2, at least any of the inside and outside of the coil Temper color is generated in one, it can be seen that the surface quality of the coil is lower than the embodiment of the present invention.

Further, in Comparative Examples 1 and 2, the difference in grain size inside and outside the coil is 3 μm to 1.5 μm, but according to the embodiment of the present invention, the difference in grain size inside and outside the coil is only 0.3 μm. In addition, in Comparative Examples 1 and 2, the yield strength difference between the inside and the outside of the coil is 15 MPa to 30 MPa, but according to the embodiment of the present invention, the difference in yield strength between the inside and the outside of the coil is only 7 MPa.

That is, in the embodiment of the present invention, the temperature difference at which the inside and the outside of the coil are annealed is less than 50 ° C. In Comparative Examples 1 and 2, the temperature difference at which the inside and the outside of the coil is annealed is at least 50 ° C and up to 100 ° C. It can be seen that the results shown in Table 1 according to the generation, according to the embodiment of the present invention can greatly improve the quality of the coil by greatly reducing the variation in the material characteristics of the inner and outer coils Able to know.

5 is a cross-sectional view of a batch annealing furnace according to another embodiment of the present invention. More specifically, FIG. 5 is an auxiliary heating apparatus described with reference to FIGS. 1 to 3 in a parallel batch annealing furnace 101 in addition to a batch annealing furnace (100 in FIG. 1) for stacking coils in multiple stages (FIG. 1 of 80) is applied. Meanwhile, in describing FIG. 5, components described above with reference to FIGS. 1 to 3 are denoted by reference numerals, and redundant descriptions of the components are omitted.

Referring to FIG. 5, a fixed base 1 is provided below the parallel batch annealing furnace 101, and a load plate 35 supporting the load of the coil CL is provided on the fixed base 1. . On the road plate 35, coils CL are arranged in parallel in three rows in one stage.

A gas supply pipe 45 is provided below the road plate 35, and an inert gas such as argon gas may be provided to the chamber 5 through the gas supply pipe 45. In addition, the upper end of the chamber 5 is provided with an exhaust fan 90, the inert gas provided into the chamber 5 through the exhaust fan 90 may be exhausted to the outside.

In addition, the main heater 20 is provided in plurality and disposed on the inner wall of the chamber 5, and in addition to the mail heater 20 shown in FIG. 5, the main heater 20 has a front surface of the coil CL. It may be arranged on the inner wall of the chamber 5 to face the part and the rear part. In the embodiment of the present invention shown in Figure 5, the main heating device 20 may be implemented as an electric heating element for generating heat by receiving power from the outside.

On the other hand, in the parallel batch annealing furnace 101 having the above-described structure, since a total of three coils CL are arranged in parallel in three rows in one stage, the auxiliary heating device 80 is also one-to-one with three coils CL. A total of three are arranged to correspond.

In the auxiliary heating device 80, first to third heating members 71, 72 and 73 of FIG. 2 are sequentially disposed from the upper side to the lower side as described in FIG. Accordingly, when the inside of the chamber 5 is a vacuum atmosphere, the outer side S2 of the coil CL is uniformly heated by the radiant heat generated from the main heating device 20, and the first to the first 3, the upper end, the center, and the lower end of the inner side S1 of the coil CL may be uniformly heated by the radiant heat generated from the heating members.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. You will understand.

CL: coil S1: inner
S2: outer side 50: heat circulation part
60: support 70: heating member
80: auxiliary heater 20: main heater
100: batch annealing furnace 101: parallel batch annealing furnace

Claims (12)

chamber;
A main heating device provided in the chamber to generate heat; And
An auxiliary heating device configured to generate heat from the wall of the chamber rather than the main heating device in the chamber,
The auxiliary heating device,
A support extending from the bottom of the chamber in a height direction of the chamber;
A heating member provided on the support; And
Batch annealing furnace characterized in that at least one opening is formed to include a heat circulation portion provided on the upper end of the support. The batch annealing furnace according to claim 1, wherein a coil loading space in which the coil is mounted between the wall of the chamber and the support is defined in the chamber, and the heat circulation part covers the coil loading space. According to claim 2, wherein the coil is wound in the coil loading space, the main heating device is adjacent to the outer side of the wound coil, the heating member is located closer to the inner side than the outer side of the wound coil. Characterized by batch annealing furnace. 3. The batch annealing furnace according to claim 2, wherein the support is spaced apart from the coil loading space. The batch annealing furnace according to claim 4, wherein the support has a hollow cylindrical shape. 6. The batch annealing furnace according to claim 5, wherein an outer diameter of the support is at least 20% of the width of the coil wound. 6. The batch annealing furnace according to claim 5, wherein the heating member is provided along an outer circumferential surface of the support. 6. The arrangement annealing according to claim 5, wherein a portion corresponding to the hollow position of the support is removed from the heat circulation portion to form a vent hole, and the heat circulation portion has a plate shape having a circular edge on a plane. in. 3. The batch annealing furnace according to claim 2, wherein the coil comprises titanium and a titanium alloy. Providing a coil in a chamber of a batch annealing furnace;
Creating a vacuum atmosphere in the chamber;
Heating the inner side of the coil separately from the outer side of the coil to firstly anneal the coil in the vacuum atmosphere;
Releasing a vacuum atmosphere in the chamber;
Providing an inert gas into the chamber; And
And annealing the coil by heating the coil, wherein the coil is annealed using a batch annealing furnace. 12. The method of claim 10, wherein in the first annealing step, heating apparatuses for heating the inner side of the coil and the outer side of the coil are separately provided. The method of claim 10, wherein the batch annealing furnace is provided with a coil including titanium and a titanium alloy.

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