JP6254754B2 - Heating method of heated material - Google Patents

Description

  The present invention uses a heating furnace that heats and extracts the material to be heated inserted into the furnace in the furnace length direction so that the longitudinal direction of the material to be heated becomes the furnace width direction. The present invention relates to a method for heating a material to be heated.

  For example, a continuous heating furnace (hereinafter, referred to as a heating furnace) of a hot rolling facility is installed so that the longitudinal direction of rolling of a slab (material to be heated) such as a slab, billet, or bloom is the furnace width direction. While the slab charged into the furnace from the entrance is transported by walking beam (conveying means), the slab is passed by the burner in the furnace while passing through the pre-tropical zone, heating zone, and soaking zone in the furnace. After heating to a predetermined temperature, it is extracted out of the furnace through the extraction port. And the heated steel slab is sent to the rolling line of the next process.

  Also, recently, not only the steel slab is heated uniformly throughout, but also in the furnace width direction so that the temperature distribution is inclined between the front end side and the rear end side in the rolling longitudinal direction of the steel slab. The steel slab is heated (referred to as gradient heating) by changing the temperature of (see, for example, Patent Documents 1 and 2).

  For example, when a thin steel plate is manufactured by hot rolling, the time from the start of rolling from the tip of the steel slab to the end of rolling at the rear end becomes longer. Decrease increases (referred to as thermal down). In this case, when the rear end side of the steel slab becomes lower than the target finish rolling temperature, the deformation resistance increases, leading to deterioration of the shape due to load fluctuation. Therefore, in anticipation of such a temperature drop on the rear end side of the steel slab, the gradient heating is performed so that the temperature on the rear end side of the steel slab becomes higher than the temperature on the front end side. Thereby, the rear end side of the steel slab can be rolled within the range of the target finish rolling temperature, and the load fluctuation on the rear end side of the steel slab can be reduced.

JP 2009-161837 A JP 2009-263701 A Japanese Patent Application Laid-Open No. 11-323431

Incidentally, in the oven, from the viewpoint of reduction of the fuel consumption and CO ₂ emissions, using waste heat recovered by the combustion air can be preheated to a regenerative burner of the combustion exhaust gas (regenerative burners) In order to improve energy efficiency (energy saving), efforts are being made.

  Specifically, in a heating furnace equipped with a regenerative burner, alternating alternating combustion and exhaust are repeated between a pair of regenerative burners arranged opposite to each other across the conveying path of the material to be heated. While performing combustion, the exhaust heat of the combustion exhaust gas is stored and recovered by the heat storage body during exhaust, and the combustion air is preheated by the heat stored in the heat storage body during combustion.

  However, in a heating furnace equipped with such a regenerative burner, since a combustion frame (flame) is formed between regenerative burners arranged in the furnace width direction, the temperature distribution in the furnace width direction is controlled. It was difficult to change the temperature in the furnace width direction as described above and to heat the steel slab at an inclined temperature.

  For this reason, apart from the plurality of regenerative burners arranged in the furnace length direction of the heating furnace, a plurality of continuous burners are arranged in the furnace width direction, and the combustion amount between the plurality of continuous burners arranged in the furnace width direction The temperature distribution in the furnace width direction is controlled while adjusting (see Patent Document 3).

  However, in the invention described in Patent Document 3, since it is difficult to control the temperature distribution in the furnace width direction using a plurality of regenerative burners arranged in the furnace length direction, main combustion is performed with the regenerative burner, Combustion necessary for temperature control must be performed by a continuous burner, and the combustion of the regenerative burner is not necessarily utilized to the maximum extent.

  The present invention has been proposed in view of such conventional circumstances, and in a heating furnace equipped with a heat storage burner, the temperature distribution in the furnace width direction is controlled using the heat storage burner. It is an object of the present invention to provide a method for heating a material to be heated that makes it possible to more efficiently perform inclined heating on the heating material.

The gist of the present invention aimed at solving the above problems is as follows.
(1) While transporting the material to be heated inserted in the furnace in the furnace length direction so that the longitudinal direction of the material to be heated is the furnace width direction, A heating method of a heated material using a heating furnace that heats the heated material and extracts it outside the furnace while sequentially passing through the heating zone and the soaking zone,
A plurality of a pair of regenerative burners facing each other in the furnace width direction of the heating furnace are arranged side by side in the furnace length direction, and the number of regenerative burners arranged in the furnace length direction is ½ or less of the whole in the soaking zone. ,
A roof burner that is a non-heat storage burner is arranged side by side in the furnace length direction and the furnace width direction in the top of the furnace chamber on the upper side of the soaking zone,
A plurality of short flame burners that generate a flame shorter than the flame length of the regenerative burner on the side of the furnace chamber at the lower part of the soaking zone are arranged in the furnace length direction.
The regenerative burner opposed to each other in the furnace width direction so as to form a combustion frame opposite to each other between a pair of regenerative burners opposed to each other in the furnace length direction adjacent to the soaking zone. In addition, alternating combustion that alternately switches between combustion and exhaust gas was performed, and the heat storage burner on the exhaust side collected and recovered exhaust heat from the combustion exhaust gas by the heat storage body, and the heat storage burner on the combustion side was stored in the heat storage body Preheat combustion air with heat,
In addition, there is a difference in the amount of combustion between the plurality of regenerative burners arranged on one side in the soaking zone and the plurality of regenerative burners arranged on the other side in the furnace width direction. Excluding the case where there is a difference in the amount of combustion in both the tropical and soaking tropics),
Furthermore, the combustion amount of the roof burner in a plurality of heating regions divided in the furnace width direction of the furnace chamber top on the upper side of the soaking zone on the side of raising the temperature of the material to be heated is the temperature distribution in the furnace width direction. Step by step to match the slope of the
Further, by increasing the combustion amount of the short flame burner on the side of the furnace chamber on the lower side of the soaking zone on the side of raising the temperature of the heated material, the temperature distribution in the soaking zone in the width direction of the furnace is inclined. Give the material to be heated that passes through the soaking zone inclined heating,
In addition, by increasing or decreasing the combustion amount of the regenerative burner disposed on the side opposite to the side where the temperature is desired to be raised or lowered in the soaking zone width direction, the temperature distribution in the soaking zone width direction Is set to be higher or lower on the side opposite to the regenerative burner.
(2) The method for heating a material to be heated according to (1), wherein the number of regenerative burners arranged in the furnace length direction is 1/3 or less of the whole in the soaking zone.

  As described above, in the present invention, a plurality of a pair of regenerative burners facing each other in the furnace width direction of the heating furnace are arranged side by side in the furnace length direction, and the number of regenerative burners arranged in the furnace length direction is the whole in the soaking zone. When the material to be heated passes through the pre-tropical zone and the heating zone in the furnace, the material to be heated is sufficiently heated to a necessary temperature. Capability can be secured.

  Further, in the present invention, while the material to be heated passes through the soaking zone in the furnace, the furnace width is formed so as to form combustion frames in opposite directions between the regenerative burners adjacent in the soaking zone direction of the soaking zone. Alternating combustion is performed by alternately switching between combustion and exhaust between regenerative burners facing each other in the direction. At this time, it is possible to prevent a local temperature rise due to the collision of the combustion flame.

  In the present invention, the exhaust-side regenerative burner heat-collects and recovers the exhaust heat from the combustion exhaust gas by the regenerator, the combustion-side regenerative burner preheats the combustion air with the heat stored in the regenerator, and By providing a difference in the amount of combustion between a plurality of regenerative burners arranged on one side in the soaking zone and a plurality of regenerative burners arranged on the other side in the furnace length direction, The temperature distribution in the furnace width direction is inclined, and the heated material passing through the soaking zone is inclined and heated.

  In particular, in the present invention, by increasing or decreasing the combustion amount of the regenerative burner disposed on the side opposite to the side where the temperature is desired to be increased or decreased in the soaking zone width direction (longitudinal direction of the material to be heated), It is possible to set the temperature distribution in the direction of the soaking zone in the soaking zone to be higher or lower on the side opposite to the regenerative burner.

  As a result, in the present invention, by using a regenerative burner arranged in the direction of the soaking zone in the soaking zone, while controlling the temperature distribution in the soaking zone width direction, the heated material passing through the soaking zone is inclinedly heated. Can be performed efficiently.

FIG. 1 is a schematic diagram showing an example of a continuous hot rolling line. FIG. 2 is a perspective view showing the configuration of the heating furnace. FIG. 3 is a plan view showing the configuration of the heating furnace. FIG. 4 is a side view showing the configuration of the heating furnace. FIG. 5 is a plan view showing a soaking configuration. FIG. 6 is a cross-sectional view showing a soaking zone configuration. FIG. 7 is a graph showing a temperature distribution in the soaking zone width direction. FIG. 8 is a graph showing a temperature distribution in the furnace width direction of the bloom during extraction.

Hereinafter, a heating method of a material to be heated to which the present invention is applied will be described in detail with reference to the drawings.
In the present embodiment, a case where a slab (material to be heated) is heated before rolling in a continuous hot rolling line 101 as shown in FIG. 1 will be described as an example.

  In this continuous hot rolling line 101, as shown in FIG. 1, after the slab is heated in the heating furnace 1, the oxide scale and the like generated on the surface of the slab are removed by the descaling device 2, and the rough rolling mill 3 and finish This is a facility in which a belt-shaped steel sheet rolled to a predetermined plate thickness by a rolling mill 4 is cooled by a cooling facility 5 and then wound into a roll by a winder 6.

  And in the said heating furnace 1, using the heating method of the to-be-heated material to which this invention is applied, a furnace is provided so that temperature distribution may be inclined between the front end side and the rear end side in the longitudinal direction of the slab rolling. Inclination heating of the slab S is performed by changing the temperature in the width direction.

  Specifically, as shown in FIGS. 2, 3, and 4, the heating furnace 1 includes a charging port 10 a into which the slab S before heating is inserted at one end side, and a slab S after heating at the other end side. And a furnace chamber 10 provided with an extraction port 10b from which water is extracted.

  The interior of the furnace chamber 10 is partitioned into a pre-tropical zone 10A, a heating zone 10B, and a soaking zone 10C in order from the loading port 10a side in the furnace length direction. The pretropical zone 10A, the heating zone 10B, and the soaking zone 10C may be partitioned by a partition wall 11 that protrudes from the top and floor of the furnace chamber 10 and extends in the furnace width direction. .

  The heating furnace 1 includes a conveying means such as a walking beam in the furnace chamber 10, and a conveying path T for conveying the slab S is formed by the conveying means. The slab S is charged into the furnace from the charging port 10a of the furnace chamber 10 so that the rolling longitudinal direction is the furnace width direction. The slab S is extracted from the extraction port 10b of the furnace chamber 10 to the outside of the furnace after sequentially passing through the pre-tropical zone 10A, the heating zone 10B, and the soaking zone 10C in the furnace chamber 10 while being conveyed by the conveying means. Will be.

  The heating furnace 1 includes a plurality of regenerative burners (regenerative burners) 12 as heating means for heating the slab S in the furnace chamber 10. The plurality of regenerative burners 12 are arranged on both upper and lower side surfaces sandwiching the transport path T of the pretropical zone 10A and heating zone 10B, and on both lower side surfaces sandwiching the transport path T of the soaking zone 10C. Each is provided side by side in the furnace length direction.

  In the present invention, the number of regenerative burners arranged in the furnace length direction is set to 1/2 or less, preferably 1/3 or less of the whole in the soaking zone 10C. Thus, while the slab S passes through the pre-tropical zone 10A and the heating zone 10B in the furnace, the slab S is sufficiently heated to a required temperature, while the slab S passes through the soaking zone 10C in the furnace. In addition, inclined heating is performed on the slab S passing through the soaking zone 10C.

  Specifically, on the lower side of the soaking zone 10C, as shown in an enlarged view in FIG. 5, the first and second regenerative burners 12A and 12B disposed opposite to each other on both sides of the conveyance path T. The first and second heat storage burners 12A and 12B and the third and fourth heat storage burners 12C and 12D arranged adjacent to each other in the furnace length direction constitute one heating zone H. . Note that one heating zone H is configured on each of the upper and lower sides of the pre-tropical zone 10A and the heating zone 10B, and two heating zones H are configured on the lower side of the soaking zone 10C.

  Further, between the first heat storage burner 12A and the third heat storage burner 12C, and between the second heat storage burner 12B and the fourth heat storage burner 12D, the combustion exhaust gas G is emitted during exhaust. A heat exchanger (heat exchange means) 14 is provided for collecting and recovering the exhaust heat from the heat storage body 13 and preheating the combustion air K with the heat stored in the heat storage body 13 during combustion.

  Thereby, in each heating zone H, between the 1st heat storage type burner 12A and the 2nd heat storage type burner 12B, and between the 3rd heat storage type burner 12C and the 4th heat storage type burner 12D, While alternating combustion is performed by alternately switching between combustion and exhaust, the first heat storage burner 12A and the third heat storage burner 12C, and the second heat storage burner 12B and the fourth heat storage burner are used. Between 12D, it is possible to perform exhaust heat recovery from the combustion exhaust gas G and preheat the combustion air K.

  FIG. 5 illustrates a state where the combustion side is the first and fourth heat storage burners 12A and 12D, and the exhaust side is the second and third heat storage burners 12B and 12C. Specifically, in the first and fourth regenerative burners 12A and 12D on the combustion side, the combustion air K and the fuel E preheated by the heat accumulator 13 are supplied, so that the combustion is reversed in the furnace width direction. A frame (flame) Fr is formed. In the present invention, it is possible to prevent a local temperature rise by avoiding the collision of the combustion flame Fr in this way.

  On the other hand, in the second and third regenerative burners 12B and 12C on the exhaust side, exhaust heat from the combustion exhaust gas G is exhausted while exhausting the combustion exhaust gas G from the first and fourth heat storage burners 12A and 12D. Heat storage and recovery are performed by the heat storage body 13. Further, when the combustion side is the second and third heat storage burners 12B and 12C and the exhaust side is the first and fourth heat storage burners 12A and 12D, the illustration is omitted, but the reverse It becomes operation.

  Although not shown, the heating furnace 1 includes a control unit (control means) including a microcomputer (CPU) that controls each unit. The heating furnace 1 switches between combustion and exhaust of the first to fourth regenerative burners 12A to 12D and adjusts the combustion amount of each regenerative burner 12A to 12D based on a control signal from the control unit.

  And in the heating method of the to-be-heated material to which this invention is applied, the 1st and 3rd regenerative burners 12A and 12C arranged on one side in the furnace width direction of the soaking zone 10C and the first arranged on the other side in the furnace length direction. The temperature distribution in the furnace width direction of the heating zone H is controlled by adjusting the amount of combustion between the second and fourth heat storage burners 12B and 12D.

  Specifically, the temperature distribution in the furnace width direction of the heating zone H is increased by increasing (or decreasing) the combustion amount of the regenerative burner on the side opposite to the side where the temperature is desired to be increased in the rolling longitudinal direction of the slab S. It can be set higher (or lower) on the side opposite to the regenerative burner. That is, the temperature distribution in the furnace width direction of the heating zone H is the ratio of the combustion amount between the first and third heat storage burners 12A and 12C and the second and fourth heat storage burners 12B and 12D. It can be increased (or decreased) at the opposite rate.

  Accordingly, in the present invention, the slab S that passes through the heating zone H is controlled using the heating furnace 1 having such heat storage burners 12A to 12D while controlling the temperature distribution in the furnace width direction of the heating zone H. In contrast, it is possible to perform gradient heating.

  In addition to the heat storage burners 12A to 12D, a non-heat storage burner for performing inclined heating on the slab S can be disposed in the heating furnace 1. Specifically, as shown in FIGS. 2 to 4 and 6, a plurality of roof burners 15 that form a combustion frame Ft downward from the top of the furnace chamber 10 are provided on the upper side of the soaking zone 10C. ing.

  The plurality of roof burners 15 are arranged side by side in the furnace length direction and the furnace width direction at the top of the furnace chamber 10, and adjust the combustion amount for each of the plurality of regions H1 to H4 divided in the furnace width direction. Thus, the temperature distribution in the furnace width direction can be controlled.

  Specifically, the temperature distribution in the furnace width direction is increased (or decreased) on the roof burner 15 side by increasing (or decreasing) the combustion amount of the roof burner 15 on the side where the temperature is desired to be increased in the rolling longitudinal direction of the slab S. Can be set to In FIG. 6, the temperature distribution in the furnace width direction can be increased in the order of the region H1> H2> H3> H4 by increasing the combustion amount in the order of the region H1> H2> H3> H4.

  Therefore, in the present invention, the slab S passing through the soaking zone 10C can be subjected to the gradient heating by the roof burner 15 in addition to the gradient heating by the heat storage burners 12A to 12D.

  In addition to the heat storage burners 12A to 12D and the roof burner 15 that perform the inclined heating, the heating furnace 1 can be provided with a non-heat storage burner for performing local heating on the slab S. . Specifically, as shown in FIGS. 2 to 4 and 6, a plurality of short flame burners 16 are provided on the lower side of the soaking zone 10 </ b> C.

  The short flame burner 16 is disposed on the side surface of the furnace chamber 10 on the side where the temperature of the slab S is desired to be raised, and has a combustion frame Fs shorter than the combustion frame Fr formed by the heat storage burners 12A to 12D in the furnace width direction. Form. Thereby, the side which wants to raise the temperature of the slab S can be heated locally.

  As described above, in the method for heating a material to be heated to which the present invention is applied, a plurality of a pair of regenerative burners 12 facing each other in the furnace width direction of the heating furnace 1 are arranged side by side in the furnace length direction, By setting the number of the regenerative burners 12 to be ½ or less, preferably １ ／ or less of the total in the soaking zone 10C, the slab S passes through the pre-tropical zone 10A and the heating zone 10B in the furnace. In addition, it is possible to ensure the ability to sufficiently heat the slab S to the required temperature.

  In the present invention, while the slab S passes through the soaking zone 10C in the furnace, between the first heat storage burner 12A and the third heat storage burner 12C adjacent in the furnace length direction of the soaking zone 10C, In addition, the first heat storage burner 12A and the first heat storage burner 12A facing each other in the furnace width direction and the second heat storage burner 12D and the fourth heat storage burner 12D are formed so as to form a combustion frame opposite in direction to each other. Alternate combustion is performed by alternately switching combustion and exhaust between the second heat storage burner 12B and between the third heat storage burner 12C and the fourth heat storage burner 12D. At this time, it is possible to prevent a local temperature increase due to the collision of the combustion flame Fr.

  In the present invention, the exhaust-side regenerative burners 12A, 12D (or 12B, 12C) collect and recover the exhaust heat from the combustion exhaust gas G by the heat accumulator 13, and the combustion-side regenerative burners 12B, 12C (or 12A). , 12D) preheats the combustion air K with the heat stored in the heat accumulator 13, and the first and third regenerative burners 12A, 12C lined up on one side in the furnace width direction of the soaking zone 10C, By providing a difference in the amount of combustion between the second and fourth heat storage burners 12B and 12D arranged on the other side in the longitudinal direction, the temperature distribution in the furnace width direction of the soaking zone 10C is inclined. Then, the slant heating is performed on the slab S passing through the soaking zone 10C.

  In particular, in the present invention, the regenerative burners 12A, 12C (or 12B, 12D) disposed on the opposite side of the soaking zone 10C in the furnace width direction (longitudinal direction of the slab S) from the side where the temperature is desired to be raised or lowered. By increasing or decreasing the combustion amount, it is possible to set the temperature distribution in the furnace width direction of the soaking zone 10C to be higher or lower on the side opposite to the regenerative burner 12A, 12C (or 12B, 12D). .

  Thereby, in this invention, since the temperature distribution of a furnace width direction can be changed using the some thermal storage type burner 12 located in a line with a furnace length direction, it is possible to perform gradient heating with respect to the slab S more efficiently. It is.

  As described above, according to the present invention, in anticipation of the temperature decrease on the rear end side of the slab S due to the above-described thermal down, the temperature on the rear end side of the slab S is set higher than the temperature on the front end side. Since the temperature distribution in the rolling longitudinal direction can be inclined, the continuous hot rolling line 101 can be rolled from the front end to the rear end of the slab S within the target finish rolling temperature range. Become.

In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in the heating furnace 1, by providing a difference in the combustion amount between the first and third regenerative burners 12A and 12C and the second and fourth regenerative burners 12B and 12D, the heating zone H Although it is possible to perform inclined heating on the slab S that passes through, the amount of combustion between the first and third heat storage burners 12A, 12C and the second and fourth heat storage burners 12B, 12D When the slab S is heated without providing a difference, it is possible to uniformly heat the front end and the rear end in the rolling direction of the slab S.

  However, it is known that in general alternating combustion using a regenerative burner, the temperature distribution in the furnace width direction tends to be higher at the center side than the end side, which is called the middle-high tendency. Therefore, when uniform heating is performed without providing a difference in the amount of combustion between the first and third heat storage burners 12A and 12C and the second and fourth heat storage burners 12B and 12D, such a medium-high Although it is possible to show a tendency, by adjusting the combustion amount between the 1st and 3rd regenerative burners 12A and 12C and the 2nd and 4th regenerative burners 12B and 12D, It is also possible to make the temperature distribution more flat.

Further, in the heating furnace 1, in order to further reduce the fuel consumption and the CO ₂ emission amount, regenerative burners 12A to 12D capable of controlling the temperature distribution in the furnace width direction are arranged instead of the roof burner 15. It is also possible to do. The short flame burner 16 compensates for the insufficient heating amount generated in the rolling longitudinal direction of the slab S described above, and may be disposed (or operated) as necessary, and may be omitted. is there.

  Further, the present invention is not limited to the case where the slab S is heated before rolling in the continuous hot rolling line 101, but as a material to be heated, in addition to the slab S, billets, blooms, and the like. The present invention is also applicable when heating a slab or when heating a non-ferrous metal.

  Hereinafter, the effects of the present invention will be made clearer by examples. In addition, this invention is not limited to a following example, In the range which does not change the summary, it can change suitably and can implement.

In this example, a simulation was performed in which the material to be heated is heated by using the heating furnace 1. Specifically, FLUENT manufactured by ANSYS was used as heat flow analysis software. The calculation conditions are as follows: bloom as the material to be heated (length 11750 mm × width 380 mm × height 315 mm), spacing between blooms arranged in the transport direction is 125 mm, entrance temperature to the heating furnace is 1200 ° C., and bloom transport speed is 3 .6 minute pitch (1.76 mm / s), and the total combustion amount of the heating furnace was 3 million kcal / hr. The size of the heating furnace is 7600 mm long × 13500 mm wide × 2200 mm high, the air ratio is 1.1, the fuel composition is (CH ₄ : 90.56%, C ₂ H ₆ : 5.82%, C _{3 H 8: 2.59%, i-} C 4 H 10: 0.52%, n-C 4 H 10: 0.50%, i-C 5 H 12: 0.01%,), the preheated air temperature The nozzle cooling air amount was constant at 1000 ° C. and 1% of the required combustion air amount at the time of maximum combustion (the number of combustion air amount).

  Also, physical phenomena include turbulent flow of furnace gas, combustion reaction of fuel and combustion air, radiant heat transfer between furnace gas-bloom and furnace wall, heat transfer inside wall, and heat transfer inside bloom, They were handled as shown in Table 1. Since these are all implemented in the thermal flow analysis software, we decided to use them.

  And in Example 1, the number of the regenerative burners arranged in the furnace length direction is 1/3 of the whole in the soaking zone, and the ratio of the combustion amount in the soaking zone width direction in the soaking zone is the front end of the bloom: the rear end of the bloom = 1: 1.4 (1.25 million kCal / hr: 1.75 million kCal / hr) In Example 2, the ratio of the amount of combustion in the soaking zone in the width direction of the soaking zone is defined as the front end of the bloom: the rear end of the bloom = 1: 2. (Million kCal / hr: 2 million kCal / hr) In Comparative Example 1, the ratio of the amount of combustion in the soaking zone in the soaking zone is the front end of the bloom: the rear end of the bloom = 1: 1 (1.5 million kCal / hr: 150 kCal / hr), and the temperature distribution in the heating zone was determined. The result is shown in FIG. 7 represents the furnace width position (m) of the heating zone, and the vertical axis represents the average gas temperature (° C.) between the furnace height and the furnace length.

  As shown in FIG. 7, in Examples 1 and 2, the gas temperature is high on the front end side where the amount of combustion is small, and it is possible to have a temperature distribution inclined in the furnace width direction of the heating zone. On the other hand, Comparative Example 1 shows a medium-high distribution in which the temperature on the center side is higher than that on the end side in the furnace width direction of the heating zone.

  Moreover, about these Examples 1, 2 and the comparative example 1, the temperature distribution in the furnace width direction of the bloom at the time of extraction was calculated | required. The result is shown in FIG. In addition, the horizontal axis of FIG. 8 represents the furnace width position (m) of the bloom, and the vertical axis represents the cross-sectional average temperature (° C.) of the bloom.

  As shown in FIG. 8, in the first and second embodiments, the cross-sectional temperature of the bloom is high on the front end side where the combustion amount is small, and it is possible to have a temperature distribution inclined in the furnace width direction of the bloom. On the other hand, Comparative Example 1 shows a medium-high distribution in which the temperature on the center side is higher than the end side in the furnace width direction of the bloom.

  From the above, in the present invention, the heat storage burner arranged in the direction of the soaking zone in the soaking zone is used to control the temperature distribution in the soaking zone width direction, while the material to be heated passing through this soaking zone is controlled. It is possible to efficiently perform the gradient heating.

  From the results shown in FIG. 7 above, when the total fuel flow rate is the same, the temperature decreases as a whole. Therefore, when inclined heating is performed in the entire furnace length direction of the heating furnace, On the other hand, the average temperature of the bloom is lowered. Therefore, in order to efficiently perform the gradient heating, it is desirable that the number of regenerative burners that perform the gradient heating as in the present invention is ½ or less, preferably ３ or less of the whole.

  DESCRIPTION OF SYMBOLS 1 ... Heating furnace 2 ... Descaling device 3 ... Rough rolling mill 4 ... Finishing mill 5 ... Cooling equipment 6 ... Winding machine 10 ... Furnace room 10a ... Loading port 10b ... Extraction port 10A ... Pre-tropical zone 10B ... Heating zone 10C ... Soaking zone 11 ... Partition wall 12A ... First heat storage burner 12B ... Second heat storage burner 12C ... Third heat storage burner 12D ... Fourth heat storage burner 13 ... Heat storage body 14 ... Heat exchanger 15 ... Roof burner 16 ... Short flame burner 101 ... Continuous hot rolling line

Claims (2)

While transporting the material to be heated inserted in the furnace in the furnace length direction so that the longitudinal direction of the material to be heated is the furnace width direction, And a heating method of a heated material using a heating furnace that heats the heated material and extracts it outside the furnace while sequentially passing through the soaking zone,
A plurality of a pair of regenerative burners facing each other in the furnace width direction of the heating furnace are arranged side by side in the furnace length direction, and the number of regenerative burners arranged in the furnace length direction is ½ or less of the whole in the soaking zone. ,
A roof burner that is a non-heat storage burner is arranged side by side in the furnace length direction and the furnace width direction in the top of the furnace chamber on the upper side of the soaking zone,
A plurality of short flame burners that generate a flame shorter than the flame length of the regenerative burner on the side of the furnace chamber at the lower part of the soaking zone are arranged in the furnace length direction.
The regenerative burner opposed to each other in the furnace width direction so as to form a combustion frame opposite to each other between a pair of regenerative burners opposed to each other in the furnace length direction adjacent to the soaking zone. In addition, alternating combustion that alternately switches between combustion and exhaust gas was performed, and the heat storage burner on the exhaust side collected and recovered exhaust heat from the combustion exhaust gas by the heat storage body, and the heat storage burner on the combustion side was stored in the heat storage body Preheat combustion air with heat,
In addition, there is a difference in the amount of combustion between the plurality of regenerative burners arranged on one side in the soaking zone and the plurality of regenerative burners arranged on the other side in the furnace width direction. Excluding the case where there is a difference in the amount of combustion in both the tropical and soaking tropics),
Furthermore, the combustion amount of the roof burner in a plurality of heating regions divided in the furnace width direction of the furnace chamber top on the upper side of the soaking zone on the side of raising the temperature of the material to be heated is the temperature distribution in the furnace width direction. Step by step to match the slope of the
Further, by increasing the combustion amount of the short flame burner on the side of the furnace chamber on the lower side of the soaking zone on the side of raising the temperature of the heated material, the temperature distribution in the soaking zone in the width direction of the furnace is inclined. Give the material to be heated that passes through the soaking zone inclined heating,
In addition, by increasing or decreasing the combustion amount of the regenerative burner disposed on the side opposite to the side where the temperature is desired to be raised or lowered in the soaking zone width direction, the temperature distribution in the soaking zone width direction Is set to be higher or lower on the side opposite to the regenerative burner.   The method for heating a material to be heated according to claim 1, wherein the number of regenerative burners arranged in the furnace length direction is 1/3 or less of the whole in the soaking zone.

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