JP4216610B2 - Hot metal heating method using a grooved induction heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention uses, for example, a groove-type induction heating apparatus having a groove-type flow path provided in a storage furnace that receives pre-treated hot metal and supplies the hot metal to a refining furnace (for example, a converter). The present invention relates to a hot metal heating method.
[0002]
[Prior art]
Conventionally, hot metal discharged from a blast furnace is once received by a topped car (mixing wheel), a hot metal ladle, etc., and after the pretreatment such as desulfurization and dephosphorization is performed on this hot metal, it is supplied to a converter (smelting furnace). At this time, the supply conditions (for example, blending amount) of hot metal to the converter fluctuate due to fluctuations in the amount of hot metal discharged from the blast furnace and the amount of molten steel produced in the converter. Once stored in the furnace. This storage furnace has a volume capable of receiving hot metal from a plurality of topped cars, hot metal ladles, etc., and can not only adjust the work process but also make the hot metal components and temperature uniform, etc. . The hot metal in the storage furnace is heated by an induction heating device (also referred to as a groove type induction heating device) having a groove-type flow path provided in the storage furnace.
[0003]
As shown in FIG. 6, the heating principle of this induction heating apparatus is a transformation using an induction coil 81 of the iron core 80 as a primary circuit and a one-turn hot metal circuit 82 formed by hot metal filling the flow path as a secondary circuit. The circuit 83 can be explained.
That is, when the induction coil 81 is energized from the power supply device 84, a magnetic flux F is generated in the iron core 80, and this magnetic flux F is linked to the hot metal circuit 82 to generate an induced current I. It is heated by Joule heat generation.
In general, since the induced current I generated in the one-turn hot metal circuit 82 formed by the hot metal in the flow path is a large current, the current and the current attract each other in the flow path, and the hot metal in the flow path is generated. A force acts in the direction of contracting the cross section of the flow path.
This action is generally referred to as a pinch action (pinch effect, pinching action), and the hot metal in the flow path starts to shrink due to this pinch action, and finally the hot metal in the flow path is cut. In this way, a phenomenon in which the hot metal in the flow path contracts due to the pinch action or the hot metal in the flow path is cut by the contraction is called a pinching phenomenon (pinch phenomenon).
The occurrence of such a pinching phenomenon is the same as the state in which the large-capacity load is turned on and off intermittently, and the inrush current caused by this causes an abnormal stop of the power supply device 84, resulting in operation interruption and equipment damage. Inconvenience occurs.
[0004]
As a countermeasure, the following methods have been proposed.
For example, in Patent Document 1, an induction heating device is arranged in a tundish that casts molten steel into a mold, and when this molten steel is heated, in addition to the main channel (main channel) to be heated, a bypass channel (bypass channel) , A device that detects the pinching action in the bypass channel and controls the input power so that the molten steel is not disconnected by the pinching action based on the detected value is described. By using this device and controlling the input power, it is possible to prevent the molten steel from being separated by the pinching action.
In Patent Document 2, the current value of at least one of the fluctuating current phases of the induction heating device arranged in the tundish is detected, and a temporary delay element is added to the measured current value during operation every time the power is turned on. A method is described in which a pinch allowable value is set based on the obtained average current value, and the operation is performed while comparing this pinch allowable value with the current value during actual operation. Thereby, a sign of the pinching phenomenon can be grasped, and the occurrence of the pinching phenomenon itself can be suppressed.
Patent Document 3 detects the voltage and current applied to the induction coil of the induction heating device, stores the impedance value at the time of low output at which no pinching phenomenon occurs as a reference value, and indicates the amount of change in impedance during operation. A method of determination is described. Thereby, a sign and detection of the pinching phenomenon can be performed.
[0005]
[Patent Document 1]
Japanese Utility Model Publication No. 59-190455 [Patent Document 2]
JP-A-6-262315 [Patent Document 3]
Japanese Patent Laid-Open No. 7-236952 [0006]
[Problems to be solved by the invention]
However, the above method has the following problems.
First, in Patent Document 1, it is possible to control the input power so as not to cause a pinching action generated when heating molten steel using an induction heating device, or to disconnect the molten steel due to the pinching action. Since the deposits and precipitates generated inside can not be removed, the increase in the occurrence frequency of the pinching phenomenon due to this cannot be solved.
In addition, the method described in Patent Document 2, as in Patent Document 1, cannot remove the deposits and precipitates generated inside the flow path, thereby eliminating the increase in the occurrence frequency of the pinching phenomenon due to this. Can not do it.
The method described in Patent Document 3 operates at a limit input voltage and current value at which no pinching phenomenon occurs, and does not significantly change the input power to be applied. Therefore, it is impossible to eliminate the increase in the occurrence frequency of the pinching phenomenon due to this.
[0007]
As described above, in any of the methods, there is a problem that the occurrence frequency of the pinching phenomenon due to the deposits and precipitates generated inside the flow path increases. In addition, when the inner diameter of the flow path becomes small due to deposits or precipitates, it becomes difficult to suppress and further prevent the flow path from being blocked due to foreign substances easily clogging the flow path. And, for example, when hot metal is charged into a storage furnace having an induction heating device and the hot metal is heated and the scrap is melted into the hot metal to produce the pseudo hot metal, the pinch action on the hot metal is used. In addition, fluctuations in the voltage value and current value due to the disconnection of the hot metal flow will cause the hot metal heating efficiency to drop, and deposits and deposits will form inside the flow path for hot metal heating, resulting in pinching. Since it becomes easy and the stable heat-up is inhibited, heating power efficiency falls.
The present invention has been made in view of such circumstances, and can maintain the inside of the flow path in a normal state to suppress the pinching phenomenon, stabilize the heating operation, and improve the heating power efficiency. It is an object of the present invention to provide a hot metal heating method using a grooved induction heating device capable of suppressing and further preventing clogging of a flow path due to foreign substances.
[0008]
[Means for Solving the Problems]
The hot metal heating method using the groove type induction heating device according to the present invention in accordance with the above object is a groove type having a groove type hot metal flow path provided in a storage furnace for storing hot metal discharged from a blast furnace. A hot metal heating method in which scrap made of scrap iron is also introduced into the hot metal of the storage furnace using an induction heating device, and the temperature in the storage furnace is 1250 to 1400 degrees Celsius. High-power energization and low-power energization are alternately performed on induction heating means for melting the hot metal and heating the flow path, and the high power energization heats the hot metal in the storage furnace. The low-power energization is performed in the range of 5 to 15% of the maximum output capable of energizing the induction heating means.
In this way, a positive heating operation in which the induction heating means is energized with high output (high input power) to raise the temperature of the molten iron, and a low output energization (low input power) is applied to the induction heating means in the flow path. By alternately performing the operation of heating the hot metal passing through the flow path while forming a gentle flow, the flow path can be maintained in a normal state, pinching phenomenon can be suppressed, and the hot metal flow can be separated. The operation which prevents the blockage of the flow path can be realized, and the stable heat-up operation can be realized.
[0009]
Here, in the hot metal heating method using the grooved induction heating device according to the present invention, the flow path communicates with a storage furnace in which the hot metal is charged, and the induction heating means sandwiches or surrounds the flow path. It is preferable that the high-power and low-power energization is continuously performed, and the hot metal charged in the storage furnace is heated in the flow path and heated to return to the storage furnace. . When the hot metal is heated using a grooved induction heating device with a flow path, the hot metal charged into the storage furnace flows continuously into the flow path and is released from the flow path into the storage furnace. Is done. At this time, the hot metal flowing through the flow path is heated and heated by the Joule heat of the induction heating means, and by repeating this state, the entire hot metal in the storage furnace is heated. Here, in order to increase the absolute amount of hot metal, when scrap iron such as scrap is added to the hot metal to produce simulated hot metal, scrap iron is heated at a low temperature by carburizing action of carbon in the hot metal to scrap iron. Can be dissolved. However, in the inside of the flow path, for example, when scrap iron or hot metal is charged into the storage furnace, slag in the furnace existing above the hot metal is entrained, and deposits due to oxide generation in the furnace Blockage occurs due to the formation of deposits and clogging of foreign matters. As a result, the cross-sectional area of the flow path becomes narrower, so that the electric power flowing in the hot metal per cross-sectional area increases, the pinching phenomenon is likely to occur, the hot metal breaks off, leading to a hunting state, and stable hot metal rise. Heat becomes difficult. Therefore, the induction heating means is energized with high power to heat up the hot metal and the induction heating means is energized with low power to pass through the flow path while forming a gentle flow in the flow path. It is possible to perform stable operation by suppressing the pinching phenomenon and preventing the flow of molten iron by continuously switching the operation to heat up the molten iron alternately and heating the molten iron in the storage furnace. become. In addition, wear due to, for example, an abnormal temperature rise of the refractory forming the flow path can be prevented, and the life of the grooved induction heating device can be extended.
[0010]
In the hot metal heating method using the grooved induction heating apparatus according to the present invention, each of the high-power and low-power energizations is performed within the range of the maximum output that is more than the low-power energization and that can energize the induction heating means. It is preferable. Thereby, the hot metal heating by heating can be efficiently performed.
In the hot metal heating method using the grooved induction heating apparatus according to the present invention, the low-power energization is performed in the range of 5 to 15% of the maximum output capable of energizing the induction heating means. Thus, since the low-output energization to the induction heating means is performed in the range of 5 to 15% of the maximum output, the hot metal heating by heating can be performed more efficiently. Here, when the low output current is less than 5% of the maximum output, the heat imparted to the hot metal flowing in the flow path is insufficient, and the amount of deposits and deposits on the inner side of the flow path increases and the hot metal heating efficiency is increased. Decreases. On the other hand, when the low-power energization exceeds 15% of the maximum output, the rectification of the hot metal passing through the flow path becomes insufficient, and the effect of dissolving and washing away the deposits and deposits inside the flow path is suppressed. The flow path cannot maintain a normal size effective cross section. For this reason, a pinching phenomenon or the like due to a reduction in the cross-sectional area of the flow path is likely to occur, and there is a risk that the flow path may be blocked due to foreign matter flowing into the flow path. Therefore, to suppress the formation of deposits and deposits on the inside of the flow path, to prevent pinching phenomenon and to prevent the flow of hot metal from flowing, and to increase the heat transfer efficiency of the hot metal, it is necessary to maximize the power supply at low output. It is preferably 5 to 12% of the output, and more preferably 5 to 10%.
In the hot metal heating method using the grooved induction heating apparatus according to the present invention, it is preferable that the energization times of the high-output energization and the low-output energization are substantially the same time. Thereby, it is possible to perform energization with high output and energization with low output at a predetermined cycle, and the energization work can be simplified.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
FIG. 1 is a plan view of a heating storage furnace used in a hot metal heating method using a grooved induction heating apparatus according to an embodiment of the present invention, and FIG. FIG. 3 is a sectional view of an induction heating device used in the heating-type storage furnace, FIG. 4 is an explanatory view showing the occurrence of a pinch action, and FIG. 5 is a grooved induction heating device according to the embodiment. It is explanatory drawing of a conductance ratio when the hot metal heating method using hot metal is applied.
[0012]
As shown in FIGS. 1 and 2, a heating storage furnace (an example of a storage furnace) 10 used in a hot metal heating method using a grooved induction heating apparatus according to an embodiment of the present invention is as follows. The refractory 12 is lined on the cylindrical iron shell 11 and can be rotated with respect to the support base 13. The storage furnace body 14 can be evenly distributed in the longitudinal direction below the storage furnace body 14. It has a grooved induction heating device (hereinafter also simply referred to as induction heating device) 15 that performs six induction heatings. Above the storage furnace main body 14, a receiving port 18 is provided with an open / close lid 17 for charging the hot metal 16 after the preliminary treatment into the storage furnace main body 14 by a conveying means (not shown) such as a crane. And six loading / unloading ports 20 each provided with an open / close lid 19 for loading scrap, which is an example of scrap iron, and a spout 21 for serving the hot metal 16 inside the hot metal pan or the like. Is provided. Above the molten iron 16, there is a slag 22 mixed in the storage furnace main body 14 together with the molten iron 16.
[0013]
As shown in FIG. 3, each induction heating device 15 has a refractory 24 arranged inside an iron box 23, and the refractory 24 has a central groove communicating with the storage furnace body 14. It comprises a channel 25, bottom groove channels 26, 27 branched into two from this central channel 25, and end groove channels 28, 29 communicating from the bottom groove channels 26, 27 to the storage furnace main body 14, respectively. A flow path 30 having a circular cross section is formed. Thus, each induction heating device 15 is provided with a groove-type flow path 30. As a result, the storage furnace main body 14, the central groove 25, the bottom groove 26, and the end groove 28 form one annular path 31, and the storage furnace main body 14, the central groove 25, the bottom groove 27 and the end groove 29 constitute another annular path 32. Here, the shape and cross-sectional area of the two bottom grooves 26 and 27 are substantially the same, and the sum of the cross-sectional areas of the bottom grooves 26 and 27 is substantially the same as the cross-sectional area of the central groove 25. It has become. The shape and cross-sectional area of the two end grooves 28 and 29 are substantially the same, and the sum of the cross-sectional areas of the end groove 28 and 29 is substantially the same as the cross-sectional area of the central groove 25. It is the same. For this reason, the inflow speed of the hot metal 16 from the inside of the storage furnace body 14 to the central groove 25 and the outflow speed of the hot metal 16 from each end groove 28, 29 into the storage furnace body 14 are substantially equal. Yes.
[0014]
Each induction heating device 15 is provided with induction heating means 35 constituted by two induction coils 33 and 34, respectively. Each induction coil 33, 34 is formed by winding a coil around an iron core, and is disposed at the center of each annular path 31, 32, so that each induction coil 33, 34 uses a flow path 30 of hot metal 16. It is in the state which pinched | interposed part, ie, the center groove 25 ,.
As a result, when heating, an alternating current is applied to each induction coil 33, 34 from a power supply device (not shown), so that the hot metal 16 in the storage furnace body 14 flows from the central groove 25, and the two Two circulation flows are formed which branch into the bottom grooves 26 and 27 and then return to the storage furnace main body 14 through the end grooves 28 and 29, and the hot metal 16 is heated and raised during the circulation. Be heated. Here, the energization is controlled by a control unit that provides a voltage detector and a current detector on the outlet side of the power supply device and controls the output current of the power supply device based on the indicated value of each detector.
In addition, since the center groove 25 of the flow path 30 is sandwiched between the two induction coils 33 and 34 as described above, it is a place where the pinching phenomenon described above is likely to occur.
[0015]
Next, a hot metal heating method using the grooved induction heating apparatus according to an embodiment of the present invention will be described with reference to the heating storage furnace 10 described above.
The hot metal after the pretreatment is transported to the heating storage furnace 10 by a topped car, and then the open / close lid 17 is lifted by a crane (not shown), and the hot metal in the topped car is transferred from the receiving port 18 through the hot metal pan to the storage furnace. The main body 14 (for example, the capacity is 2000 tons) is charged. Then, each of the six induction heating means 35 having a maximum output per unit of 4.5 MW was energized, and the hot metal 16 was heated and heated. In addition, when the hot metal 16 is heated, the open / close lid 19 is opened and, for example, scrap (an example of scrap iron) collected in the city is added from the loading port 20 so that carbon in the hot metal 16 is carburized from the surface of the scrap. Thus, the scrap can be melted in a low temperature range where the hot metal temperature is 1250 to 1400 ° C. In addition, since the carbon concentration of the hot metal 16 decreases due to the melting of the scrap, a new hot metal is opened from the open / close lid 17 and is inserted through the receiving port 18 to suppress the decrease in the carbon concentration of the pseudo hot metal.
In this way, by repeatedly adding scrap and adding new hot metal, it is possible to increase production of simulated hot metal by melting large amounts of scrap, and supply the amount of simulated hot metal to the converter in an amount that matches the required amount of the converter. can do.
[0016]
In this state, the hot metal flowing through the central groove 25 sandwiched between the two induction coils 33 and 34 of the induction heating means 35 is narrowed to the central portion of the central groove 25 by the action of magnetic flux (pinch action). . As this progresses, the hot metal flow becomes smaller or a pinching phenomenon occurs, which causes the input power to fluctuate greatly (hunting). Here, when the input power fluctuates greatly, deposits and deposits are likely to be generated in the central groove 25 of the flow path 30, and the pinching phenomenon becomes more prominent as the amount of deposits and deposits increases. become. Further, in the state where the deposits and deposits are formed and the inner diameter of the flow path 30 is small, the flow path 30 is easily clogged with foreign matter, and the flow path 30 is blocked, that is, kicked.
In any of these cases, for example, hunting of input power from the power supply device, power interruption due to an excessive current value, wear of the power supply circuit, wear due to abnormal temperature rise of the refractory 24 of the induction heating device 15, inoperability. Various problems such as stabilization occur.
[0017]
Accordingly, the high-power energization and low-power are applied to the induction coils 33 and 34 in consideration of the conductance ratio obtained based on the voltage value of the voltage detector installed on the output side of the power supply device and the current value of the current detector. The energization of the output is continuously performed alternately, and the hot metal flowing in the flow path 30 is heated. It should be noted that the switching between the high output and the low output energization is performed within the range of the maximum output more than the low output energization, and the low output energization is in the range of 5 to 15% of the maximum output. Done in Here, the conductance ratio is the reciprocal of resistance and is an index for estimating the blockage state of the flow path 30. Therefore, the higher the value, the smaller the amount of deposits and deposits generated in the flow path 30, and It shows that the shape of the path 30 is maintained in a normal state.
[0018]
With this heat increase, the hot metal flow can be prevented from being restricted or blocked by an extreme pinch action, and the generation of deposits and deposits in the flow path 30 can be suppressed. Furthermore, since the formation of deposits and deposits in the flow path 30 can be prevented, it is possible to prevent kicking caused by foreign matters mixed in the flow path 30. As a result, fluctuations in the input power can be reduced, and the heating efficiency of the hot metal can be improved and the operation can be stabilized. Moreover, problems such as hunting of input power from the power supply device, power interruption due to excessive current value, wear of the power circuit, wear due to abnormal temperature rise of the refractory 24 of the induction heating device 15 can be solved, and hot metal heating and scrap A large amount of the molten iron can be melted, and the simulated molten iron can be stably supplied to the smelting furnace through the outlet 21.
[0019]
【Example】
The result of applying the hot metal heating method using the grooved induction heating apparatus according to the present invention and performing the test will be described.
First, an example of the occurrence of a pinch action will be described with reference to FIG.
In order to efficiently heat the hot metal 16 in the storage furnace main body 14, when the energization (input power) to the induction heating means 35 is 100% of the maximum output, a pinch action occurs when the conductance ratio is 93% or less. ("Pinch occurrence" in FIG. 4). Further, as the conductance ratio decreases due to the formation of deposits and deposits in the flow path 30, the pinch action occurs even at a low input power.
For this reason, when energizing necessary to maintain the hot metal 16 in the storage furnace main body 14 at a stable temperature and to return the temperature, which is lowered when scrap is melted in the hot metal 16, to the original temperature, The conductance ratio decreases due to the formation of deposits and deposits in the path 30, and a pinch action occurs, leading to current hunting and power interruption.
[0020]
Therefore, as shown in FIG. 5, the high output energization is set to 70% of the maximum output, the low output energization is set to 5% of the maximum output, and the energization time of each output is set to the same 30 minutes. Were continuously and alternately every 30 minutes for a total of 240 minutes. Here, the high-power energization is input power necessary for heating the hot metal, and the low-power energization heats the hot metal passing through the flow path 30 while forming a gentle flow in the flow path 30. This is the input power required to
As a result, the conductance ratio increases from 90% to 95% (“no pinch generation” in FIG. 4), and the deposits and deposits generated in the flow path 30 can be removed, and thereafter the deposits and deposits are removed. Since the generation can be suppressed and further prevented, and stable heating without generating a pinch action is possible, the scrap can be stably melted.
[0021]
As described above, the present invention has been described with reference to one embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and is described in the claims. Other embodiments and modifications conceivable within the scope of the above are also included. For example, the case where the hot metal heating method using the groove type induction heating apparatus of the present invention is configured by combining some or all of the above-described embodiments and modifications is also included in the scope of the present invention.
In the above embodiment, the hot metal is heated by the induction heating means arranged with the flow channel interposed therebetween. However, the hot metal can be heated by the induction heating means arranged around the flow channel. It is.
[0022]
And in the said embodiment, after the conductance ratio fell, although the case where the high output electricity supply and the low output electricity supply were performed alternately continuously was demonstrated, before the conductance ratio fell, It is also possible to carry out energization and low-power energization alternately and continuously. Thereby, in the storage furnace, the hot metal can be stably heated.
Furthermore, in the above-described embodiment, the case where the energization times of the high output energization and the low output energization are set to substantially the same time has been described. However, for example, according to the conductance ratio value, the high output energization time Can be made longer or shorter than the low-power energization time. In this case, the high-power energization time and the low-power energization time are set as one cycle, and this can be repeated.
[0023]
【The invention's effect】
In the hot metal heating method using the groove type induction heating device according to claims 1 to 3, the hot heating operation for heating the hot metal by energizing the induction heating means with high power and the induction heating means. By alternately conducting low-power energization to form a gentle flow in the flow path and heating the hot metal passing through the flow path, the flow path can be maintained in a normal state and pinching phenomenon can be suppressed. In addition, the operation of preventing the flow of the hot metal from flowing and avoiding the blockage of the flow path becomes possible, and a stable heat-up operation can be realized. Thereby, the trouble of the power supply equipment resulting from current hunting can be avoided, and problems such as operation interruption and equipment damage can be prevented. Moreover, since the production | generation of the deposit | attachment and deposit on the inner surface of a flow path can be suppressed and they can be removed, the heating efficiency of hot metal can be raised and it is economical.
In particular, in the hot metal heating method using the grooved induction heating device according to claim 2, the high power and the low power are energized alternately and continuously to heat the hot metal in the storage furnace. By doing so, it is possible to suppress the pinching phenomenon and to perform a stable operation that prevents the hot metal flow from being separated. As a result, it is possible to prevent wear due to, for example, an abnormal temperature rise of the refractory forming the flow path, and it is economical to extend the life of the grooved induction heating device. In addition, stabilization of the heat-up operation and stable melting of scrap iron, for example, can be realized, and the operation of the smelting furnace in the subsequent process can be performed stably.
[0024]
In the hot metal heating method using the groove-type induction heating device according to claim 1 , since the low output energization is performed in the range of 5 to 15% of the maximum output capable of energizing the induction heating means, The temperature can be increased more efficiently, which is economical.
In the hot metal heating method using the grooved induction heating device according to claim 3, the energization time of the high output energization and the low output energization are set to the same time, so that the high output energization and the low output energization are performed. Can be performed in a predetermined cycle, the energization work can be simplified, and the work efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is a plan view of a heating type storage furnace used in a hot metal heating method using a grooved induction heating apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
FIG. 3 is a cross-sectional view of an induction heating device used in the heating type storage furnace.
FIG. 4 is an explanatory diagram showing the occurrence of a pinch action.
FIG. 5 is an explanatory diagram of a conductance ratio when a hot metal heating method using a grooved induction heating apparatus according to an example is applied.
FIG. 6 is an explanatory diagram of a transformer circuit for explaining the heating principle of the induction heating device.
[Explanation of symbols]
10: Heated storage furnace (storage furnace), 11: Iron skin, 12: Refractory, 13: Support base, 14: Storage furnace body, 15: Groove type induction heating device, 16: Hot metal, 17: Opening and closing Lid, 18: Receiving port, 19: Opening / closing lid, 20: Loading port, 21: Outlet, 22: Slag, 23: Box, 24: Refractory, 25: Central groove, 26, 27: Bottom groove Path, 28, 29: end groove path, 30: flow path, 31, 32: annular path, 33, 34: induction coil, 35: induction heating means

Claims (3)

Using a groove type induction heating device having a channel of a groove type hot metal provided in a storage furnace for storing the hot metal discharged from a blast furnace , and scrap made of scrap iron in the hot metal of the storage furnace The method of heating
The introduced scrap is melted with hot metal having a temperature of 1250 to 1400 degrees in the storage furnace,
The induction heating means for heating the flow path alternately performs high-power energization and low-power energization, and the high-power energization heats the hot metal in the storage furnace, The hot metal heating method using a grooved induction heating device, wherein the low power supply is performed in a range of 5 to 15% of the maximum output capable of supplying the induction heating means.   The hot metal heating method using the grooved induction heating device according to claim 1, wherein the flow path communicates with the storage furnace in which hot metal is charged, and the induction heating means sandwiches the flow path or The high-power and the low-power energization is continuously performed, and the hot metal charged in the storage furnace is heated and heated in the flow path to raise the storage temperature. A hot metal heating method using a grooved induction heating device, wherein the hot metal is returned to the furnace.   In the hot metal heating method using the grooved induction heating device according to any one of claims 1 and 2, each energizing time of the high-output energization and the low-output energization is set to the same time. A hot metal heating method using a groove type induction heating device.

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