JPH09192706A - Hot rolling line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change the width of a slab during the operation of casting and to realize expansion of the range of the thickness at the end of rolling and space saving. SOLUTION: In a belt type continuous casting machine 1, a mold part 8 is formed with a pair of water-cooled belts 5 and a pair of side dams and, even during casting, the width of a slab 51 which is formed and discharged is changeable by changing the positions of the side dams. The slab 51 is rolled with an in-line rolling mill 2 just after casting and further, stored in a coil box 3. Finish rolling is executed to the sheet bar (slab) uncoiled from coil box 3 with a finishing mill 56.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling line, which is devised so that the strip width can be changed during the casting operation, and the range of the final strip thickness and the space saving can be realized. is there.

[0002]

2. Description of the Related Art FIG. 13 is a side conceptual view of a conventional plate manufacturing line constructed by being directly connected to a continuous casting machine. In the figure, 50 is a conventional continuous casting machine such as a vibration block type, 51
Is a slab molded and discharged by the continuous casting machine 50, 52 is a guide roll, 53 is a slab feed pinch roll, and 54
Is a plate cutting device continuously provided on the pinch roll 53, 55
Is a walking beam type heating furnace for heating the slab 51 sheared by the plate cutting device 54, 56 is a finishing rolling mill having a plurality of stages continuously provided to the heating furnace 55, and 57 is continuously provided to the finishing rolling device 56. Cooling runout table, 58
Is a winder.

The continuous casting machine 50 molds and discharges the slab 51 at a speed of 0.6 to 5 m / min, and the discharged slab 51 is cut into one coil unit length by a plate cutting device 54 and is sequentially tunnel type. It is stored in the heating furnace 55 and is kept warm. The slab discharged from the heating furnace 55 is accelerated to a speed of 30 m / min and supplied to the inlet side of the finish rolling mill 56, rolled by the finish rolling mill 56, passed through the cooling runout table 57, and wound on the hoisting machine 58. Taken.

[0004]

In this conventional apparatus, since the width and thickness of the mold of the continuous casting machine 50 are constant,
It is necessary to replace the mold with a different width and thickness according to the rolling schedule of the finish rolling mill 56.

Further, since the plate thickness supplied to the entrance side of the finish rolling mill 56 is large and the rolling speed is high, the finish rolling mill 5
6 requires a lot of power.

Since the finishing rolling speed is high, a linear long tunnel furnace 55 corresponding to 4 to 5 coils is required as a buffer. Further, the tunnel furnace 55 becomes longer as the plate thickness becomes thinner, which is uneconomical.

Since the casting speed is slow and the amount of decrease in plate temperature is large, it is necessary to heat the entire surface in a heating furnace (tunnel furnace) 55 or the like.

Further, since the casting speed range and the plate thickness range of the continuous casting machine 50 are narrow, there is a problem that the operating range is narrow.

In order to solve the above-mentioned conventional problems, the present invention reduces the mill power, facilitates the change of plate width, shortens the line, and expands the plate thickness range manufactured by the plate manufacturing line. An object of the present invention is to provide a hot rolling line capable of uniformizing the plate temperature, thereby expanding the operating range of the casting machine from low speed to high speed, and increasing the rolling throughput.

[0010]

In order to achieve this object, a hot rolling line according to the present invention comprises a continuous casting machine for continuously forming and discharging a slab, and a finish rolling machine provided at a stage subsequent to the continuous casting machine. In a hot rolling line with a mill,
The continuous casting machine, with a belt type continuous casting machine having a mechanism that can change the plate width during casting, between the belt type continuous casting machine and the finish rolling machine, an inline rolling machine is provided, Further, a coil box for coil holding, heating, and storage was provided between the belt type continuous casting machine and the finish rolling machine and at the subsequent stage of the inline rolling machine.

Further, a non-solidifying reduction device is provided continuously to the slab discharge port of the belt type continuous casting machine.

A plate edge heating device is provided at the entrance of the inline rolling mill.

Further, an induction heating device is provided at the entrance of the inline rolling mill instead of the plate edge heating device.

Further, the coil box is constructed so that it can be fed by plate bypass.

A sheet bar joining device is provided between the coil box and the entrance of the finish rolling mill.

In the present invention, the belt type continuous casting machine has a mechanism capable of changing the plate width during casting, and the continuously cast slab is rolled into a coil by an in-line rolling machine immediately after casting and stored in a coil box. Then, the sheet bar rewound from the coil box is continuously supplied to the entrance side of the finish rolling machine, and finish rolling is performed at a low speed linked to the casting speed of the belt type continuous casting machine.

Therefore, the thickness of the sheet bar supplied to the entrance side of the finish rolling mill is constantly reduced, and the power of the finish rolling mill can be reduced. At the same time, even if the number of finish rolling mills is the same, the plate thickness on the entry side of the finish rolling mill can be reduced, so that the range of the final rolling strip thickness can be expanded to the thin material side.

Further, since the coil box is used for intermediate winding, the space for storing the sheet bar is remarkably reduced. Further, within the range in which the plate width of the belt type continuous casting machine can be adjusted, mold replacement is unnecessary, so that the plate is not changed. The width can be easily changed, which has the effect of facilitating board production.

Further, by performing in-line reduction with a non-solidification reduction device at the mold outlet, it is possible to perform casting in which the solidification completion position can be set, thinner cast pieces can be cast, and the plate thickness of the final product can be reduced on the same rolling line. it can.

Further, immediately after casting, the plate temperature of the thin slab is made uniform by heating only the plate edge portion by the edge heating device, and it is possible to perform rolling with a good plate thickness and plate shape by the in-line rolling mill.

In addition, instead of the plate edge heating, an induction heating device is used, and by heating the entire width of the slab bar up to the required plate temperature on the inlet side of the finishing rolling mill in a heating pattern that matches the plate thickness and plate width, The plate temperature is made uniform and the plate shape during rolling is further improved, and the thin plate production range can be expanded to the low-speed casting region.

Further, for a thick plate (for example, 40 mm or more) which is difficult to wind in the coil box, the production area can be expanded to the thick plate side by passing through the bypass line of the coil box.

Further, since the plate shape is good, a constant tension is applied to the entire length of the strip by joining the leading and trailing sheet bars to each other, so that the variation in the plate thickness / shape is reduced and the yield is improved. .

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIGS. 1 to 5 show a first embodiment of the present invention. FIG. 1 is a schematic side view of the whole plate manufacturing line (hot rolling line), and FIG. 2 is an enlarged perspective view of the belt-type mold portion taken along the line III-III of FIG. 2, FIG. 4 is a partially enlarged view of FIG. 3, and FIG. 5 is a horizontal sectional view taken along the line V-V of FIG. Is. In the figure, the same elements as those of the related art are denoted by the same reference numerals as those of the related art, and redundant description will be omitted.

In FIGS. 1 and 2, 1 is a belt type continuous casting machine, 2 is an in-line rolling machine having one or a plurality of stages provided between a pinch roll 53 and a plate cutting machine 54, and 3 is a plate cutting machine 54. It is a coil box provided between the finishing rolling mill 56.

In the belt-type continuous casting machine 1, a pair of metallic water-cooled belts 5 wound endlessly on two pairs of symmetrically arranged rolls 5a are formed with gaps facing each other in the vertical direction. It is configured to move downward.
A pair of side dams 7 forming a connection body of side dam blocks that circulate at the same speed so as to be held between the opposite surfaces of the belt 5 facing each other and a pair of the water cooling belts 5 form a molding part 8. There is. In addition, 9 is a tundish arranged in the upper part of the belt type continuous casting machine 1, 10 is a nozzle for pouring the molten metal into the mold portion 8, and 11 is a circulation drive device for circulating the side dam 7.

In FIG. 3, the pair of side dams 7 are provided so as to vertically circulate a length larger than the contact length L with the slab 51 in the water cooling belt 5.

In FIGS. 3 and 5, reference numeral 12 is two side dam support plates facing each other with a fixed interval in the direction parallel to the width direction of the mold portion 8, and 13 and 14 are side dams inside the side dam support plate 12. This is a movable circulation guide in which the support plate 12 is used as a support and is movably supported in the mold width direction via an air cylinder 15. Further, 16 is a moving bearing arranged at the upper position of the movable circulation guides 13 and 14,
A drive sprocket for the circulation drive device 11 for the side dam 7 is provided on the moving bearing 16.

The side dam 7 is divided into two groups, a side dam block 7a and a side dam block 7a ', each of which is continuous in a line for half a turn. The group of side dam blocks 7a is on the movable circulation guide 13. A group of side dam blocks 7 a ′ is provided on the movable circulation guide 14.

As shown in FIG. 5, each side dam block 7a and side dam block 7a 'is provided with a guide roller 18 on the side of the arm bar 17 projecting on the rear side.
Further, each half circumference portion of the movable circulation guide 13 and the movable circulation guide 14 where the side dam block is not provided is provided with a guide block 17 ′ having a guide roller 18 ′, and the side dam block 7a and the arm bar 17 of the side dam block 7a ′ are provided. The guide block 17 'and the guide block 17' are connected endlessly with a flexible metal band or link, and the guide roller 18 of each arm bar 17 and the guide roller 18 'of the guide block 17' are respectively movable circulation guide 13 and movable circulation. It is engaged with the guide groove 20 of the guide 14 and is held so as to be patrolable.

Returning to FIG. 1 and FIG. 2, the coil box 3
Is a coil winding unit 21, a coil unwinding unit 22 that is continuously provided on the downstream side, a coil storage unit 23 that is laterally continuous from the coil unwinding unit 22, and walking for coil conveyance to the storage unit 23. Equipped with a beam 24 to keep the coil warm and heated
It is a known device for storing.

1 and 2, a plate thickness of 75 to 50 mm which is molded by the belt type continuous casting machine 1 and is molded and discharged downward.
The slab 51 is a guide roll 52 and a pinch roll 5
3 is continuously supplied to the inlet side of the in-line rolling mill 2 and rolled by the in-line rolling mill 2 to a plate thickness of about 30 mm, and the coiling unit of the coil box 3 cuts each coil unit length by the plate cutting device 54. Wind up to 21.

The wound coil is shifted from the winding unit 21 to the unwinding unit 22 by a shift device (not shown), is temporarily stored in the coil storing unit 23, and is supplied from the unwinding unit 22 to the inlet side of the finish rolling mill 56. The finish rolling machine 56 rolls the sheet to a predetermined thickness at a speed linked to the casting speed of the belt-type continuous casting machine 1, and winds it up to the winding machine 58 via the cooling runout table 57.

At this time, the belt type continuous casting machine 1
With the method described below, the width of the slab to be cast can be changed while continuing the casting operation of the belt type continuous casting machine 1.

That is, in FIGS. 3 to 5, the mold part 8 of the belt type continuous casting machine 1 holds the two rows of the movable circulation guides 13 and 14 at the maximum retracted position of the same length.
The two groups of the side dam block 7a and the side dam block 7a 'circulate at the same position on the most anti-mold side, and a certain wide slab casting is performed.

From this state, when the tip of one of the side dam blocks 7a 'reaches the upper position of the mold section 8, the movable circulation guide 14 supporting this side dam block 7a' is extended by the air cylinder 15. When it is moved to the mold part 8 side by driving, as shown in FIGS. 3 and 4, the side dam block 7a ′ group advances toward the mold part 8 side further than the lower side dam block 7a group and moves to the mold part 8 side.
Narrows. When circulating downward as it is, the molten metal surface 51a in the mold portion 8 does not fluctuate up and down, and the narrow width portion of the mold portion 8 spreads downward.

When the other side dam block 7a group circulates downward and the tip reaches a position above the mold portion 8, the movable circulation guide 13 which supports this side dam block 7a group.
When the side cylinder block 7a is moved to the same position as the lower side dam block 7a 'by moving the air cylinder 15 toward the mold portion 8 side, both side dam blocks 7a and 7a' are narrowed to the same width. Therefore, it becomes possible to continuously perform constant narrow slab casting.

When the width of the mold portion 8 is changed from the narrow width to the wide width, similarly, the movable circulation guides on the side dam block group side which are not in contact with the slab slabs in the mold are sequentially arranged above the mold portion 8. It can be performed by retracting the air cylinder 15 in the width direction of the mold portion 8 by retracting the air cylinder 15.

As a result, when changing the strip width according to the rolling schedule, it is not necessary to replace the mold, and the strip width can be easily changed while continuing the casting operation.

Further, the plate thickness of the sheet bar (slab) supplied to the entrance side of the finish rolling mill is constantly thinned, and the power of the finish rolling mill can be reduced. At the same time, even if the number of finish rolling mills is the same, the plate thickness on the entry side of the finish rolling mill can be made thin, so that the range of the final rolling strip thickness is expanded to the thin material side, which facilitates thin sheet production.

In addition, since the sheet bar (slab) is coiled in the coil box by the coil box, the temperature is kept warm.
It has the advantage of requiring less storage space.

[Second Embodiment] Next, a second embodiment of the plate manufacturing line (hot rolling line) according to the present invention will be described with reference to FIG. 6 which is a schematic side view. In this embodiment, an unsolidified rolling-down device 25 is additionally arranged continuously to the slab discharge port of the belt type continuous casting machine 1 of the first embodiment device of FIG. Reference numeral 26 is a reduction drive device of the unsolidified reduction device 25.

In this embodiment, the slab 51 whose interior is not solidified by the belt type continuous casting machine 1 is discharged by the unsolidification reduction device 25, and at this stage, the thickness of the mold portion 8 of the continuous casting machine 1 is reduced. The thin slab 51 can be continuously formed at a high casting speed.

The casting thickness can be changed without changing the mold by operating the unsolidifying reduction device 25, and the same number of in-line rolling mills 2 supplies a sheet bar having a thinner sheet thickness to the entry side of the finishing rolling mill 36. Yes, with the same number of finishing mills 36,
The final plate thickness range can be expanded to the thin side for production. Other functions and effects are similar to those of the first embodiment device.

[Third Embodiment] Next, a third embodiment of the plate manufacturing line (hot rolling line) according to the present invention will be described with reference to FIG. 7 which is a schematic side view. In this embodiment, a plate edge heating device 27 is additionally arranged on the inlet side of the inline rolling mill 2 of the second embodiment device shown in FIG.

When the apparatus of the second embodiment shown in FIG. 6 operates at high speed, a temperature drop occurs only at both side edges of the slab 51 before reaching the in-line rolling mill 2 via the unsolidification reduction device 25. Tend to do.

In the third embodiment (FIG. 7), the plate edge heating device 27 heats only both side edges of the slab 51,
The plate temperature can be made uniform and supplied to the inlet side of the in-line rolling mill 2, and the in-line rolling mill 2 due to the non-uniform plate temperature of the slab 51
The occurrence of variations in plate thickness and shape during rolling in the steel was reduced. Other functions and effects are similar to those of the second embodiment device.

[Fourth Embodiment] Next, a fourth embodiment of the plate production line (hot rolling line) according to the present invention will be described with reference to FIG. 8 which is a schematic side view. In this embodiment, the plate edge heating device 27 of the third embodiment device shown in FIG. 7 is replaced by
The induction heating device 28 is arranged on the inlet side of the inline rolling mill 2.

In this embodiment, the induction heating device 28 heats the plate temperature of the slab 51 up to the required plate temperature on the inlet side of the finishing rolling mill 56 in a heating pattern matching the plate thickness and plate width, thereby achieving a low speed casting operation range. It is possible to expand the range of plate production under in-line and produce plates with excellent plate thickness and plate shape. Other operational effects are similar to those of the second embodiment device.

[Fifth Embodiment] Next, a fifth embodiment of the plate manufacturing line (hot rolling line) according to the present invention will be described with reference to FIG. 9 which is a schematic side view. In this embodiment, the coil box 3 of the apparatus of the fourth embodiment shown in FIG. 8 is provided so as to be capable of plate bypass feeding.

FIG. 10 shows a known apparatus configuration shown as an embodiment of the coil box 3 capable of plate bypass feeding.

In FIG. 10 (a), 29 is a guide roll on the side of the plate cutting device 54, 29a is a guide roll on the exit side of the coil box 3, and 30 is a lifting cylinder with the shaft attachment portion 30a on the entrance side of the coil box 3 as a fulcrum. Two guide rolls driven up and down by 30b, 31 is two winding cradle rolls in the coil box which is driven up and down by the lifting cylinder 31b with the shaft mounting portion 31a as a fulcrum, and 32 is a supporting point 32a. A coil forming roll in a coil box which is rotated up and down by a driving device (not shown), 33
Is two cradle rolls for unwinding provided on the fixed table 33a, 34 is a bending roll in the coil box,
Reference numeral 35 is a coil movement locus from a coil winding position to a winding position by a coil shift device (not shown), 36 is a pinch roll, and 37 is a leveling roll.

FIG. 10A shows a sheet bar (slab) 51 fed from the inline rolling mill 2 side to the coil box 3.
FIG. 10B shows a state in which the rolls 30, 31, 32 and 33 are fixed guide rolls 29 and 29.
It shows a state in which the sheet bar (slab) 51 is returned to the same level as a and is fed by sheet to the finish rolling mill 56 as a plate material.

In this embodiment, a sheet bar (slab) 51 having a plate thickness of 40 mm or more, which is difficult to wind in the coil box 3 on the exit side of the inline rolling mill 2 according to the rolling schedule, is used.
, The rolls 30 to 3 of the coil box 3 are
By operating 3 in the arrangement of FIG. 10 (b) and passing the plate as it is through the bypass line to the entry side of the finish rolling mill 56, the production area of this plate manufacturing line can be expanded to the thick plate side and utilized.

In the case of a sheet bar (slab) 51 of less than 40 mm which can be wound up, the rolls 30 to 30 of the coil box 3 are used.
The sheet bar (slab) 51 can be intermediately wound by operating 33 in the arrangement shown in FIG. Other functions and effects are similar to those of the fourth embodiment.

[Sixth Embodiment] Next, a sixth embodiment of the plate manufacturing line (hot rolling line) according to the present invention will be described with reference to FIG. 11 which is a schematic side view. In this embodiment, a bar joining device 38 is additionally arranged on the entrance side of the finish rolling mill 56 of the fifth embodiment device of FIG.

FIG. 12 is a side view of an embodiment of the bar joining device 38, in which 41 is the main body structure of the joining device, 42 is a sled-shaped bottom plate, and 43 is a tunnel-shaped guide supported by the main body structure 41. Heating type joining device, 29a is coil box 3
Guide rolls on the delivery side, 44 is an elevating table provided with individually movable guide rolls 44a provided in the moving range (about 20 m) of the bar joining device 39, and 29b is the finish rolling mill 5
6 is a guide roll on the entry side.

In the bar joining device 38, a sled type bottom plate 42 is supported on a plurality of elevating guide rolls 44a of an elevating table 44, and a tunnel-shaped induction heating type joining device portion 43 is seated on the guide rolls 29a and 29b. Bar (slab) 5
It is held at a height of 1 and reciprocated along a line by a driving device (not shown).

In this embodiment, the rear end of the preceding sheet bar (slab) 51 on the side of the finish rolling mill 56 and the leading end of the following sheet bar (slab) 51 are joined by an induction heating type joining device of the bar joining device 38. It is possible to perform the bar joining while being positioned in the abutting state in the portion 43 and traveling in parallel with the bar joining device 38 at the same speed as the feeding speed of the seat bar (slab) 51.

Since the plate shape of the sheet bar (slab) 51 supplied to the inlet side of the finish rolling mill 56 is good, a constant tension is applied to the entire length of the sheet bar 51 by the bar joining in this way, and the sheet bar (slab) 51 is rolled. Variations in plate thickness and plate shape are reduced and product yield is improved.

[0062]

In summary, the hot rolling line of the present invention is a hot rolling line having a continuous casting machine for continuously forming and discharging a slab, and a finishing rolling machine provided at the subsequent stage of the continuous casting machine, The continuous casting machine, with a belt type continuous casting machine having a mechanism that can change the plate width during casting, between the belt type continuous casting machine and the finish rolling machine, an inline rolling machine is provided, Further, by providing a coil box for coil holding, heating, and storage between the belt type continuous casting machine and the finish rolling machine and at the subsequent stage of the inline rolling machine, the coil is supplied to the inlet side of the finish rolling machine. The sheet bar plate thickness is constantly thinned to reduce the power of the finishing rolling mill, and at the same time, the range of the final rolling thickness is expanded to the thin material side with the same number of finishing rolling mills, facilitating the plate production, and in the intermediate stage. Seat bar storage Significantly reduced space required, in the plate width adjustable range of the belt-type continuous casting machine, the mold replacement unnecessary and provide an advantage to facilitate the strip width changes.

Further, since the unsolidified rolling down device is continuously provided at the slab discharge port of the belt type continuous casting machine,
The effect of enabling slab casting with a good plate shape at a high casting speed was achieved.

Further, since the plate edge heating device is provided at the entrance of the inline rolling mill, the plate temperature is made uniform by heating only the plate edge, and a sheet bar having a good plate thickness and plate shape is obtained. did.

Further, by providing an induction heating device at the inlet of the inline rolling mill instead of the plate edge heating device, the induction heating device can adjust the plate thickness / width to the entry side plate temperature of the finishing rolling mill. The entire sheet bar was heated by the matched heating pattern, the plate temperature was made uniform, the plate shape during rolling was further improved, and the effect of expanding the plate production range to the low-speed casting area of about 2 m / min was achieved.

Further, since the coil box is constructed so as to be capable of plate bypass feeding, a thick plate (for example, 40 mm or more) which is difficult to wind in the coil box is passed through the bypass line of the coil box, and the production area is moved to the thick plate side. It has the effect of expanding.

Furthermore, by providing a sheet bar joining device between the coil box and the entrance of the finish rolling mill, the ends of the leading and trailing sheet bars are automatically joined so that the entire length of the sheet bar is fixed. The effect of applying tension to reduce the variation in plate thickness and shape and improving the product yield was achieved.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a hot rolling line according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a first embodiment of the present invention.

FIG. 3 is an enlarged perspective view taken along the line III-III of FIG.

FIG. 4 is an enlarged perspective view showing a part of a continuous casting machine.

5 is a horizontal cross-sectional view as seen in the direction of arrows VV in FIG.

FIG. 6 is a schematic side view showing a second embodiment of the present invention.

FIG. 7 is a schematic side view showing a third embodiment of the present invention.

FIG. 8 is a schematic side view showing a fourth embodiment of the present invention.

FIG. 9 is a schematic side view showing a fifth embodiment of the present invention.

FIG. 10 is an explanatory view showing a side view of a configuration and an operating state of a bypass feed type coil box.

FIG. 11 is a schematic side view showing a sixth embodiment of the present invention.

FIG. 12 is a side view showing the configuration of the bar connecting device.

FIG. 13 is a schematic side view showing a conventional continuous casting machine direct connection type plate manufacturing line.

[Explanation of symbols]

 1 Belt type continuous casting machine 2 In-line rolling machine 3 Coil box 5 Water cooling belt 5a Roll 7 Side dam 7a, 7a 'Side dam block 8 Mold part 9 Tundish 10 Pouring nozzle 11 Circulation drive device 12 Side dam support plate 13, 14 Movable circulation Guide 15 Air cylinder 16 Moving bearing 17 Arm bar 17 'Guide block 18, 18' Guide roller 20 Guide groove 21 Coil winding portion 22 Coil unwinding portion 23 Coil storage portion 24 Walking beam 25 Unsolidified rolling reduction device 26 Rolling down drive device 27 Plate edge Heating device 28 Induction heating device 29, 29a, 29b Guide roll 30 Guide roll 30b, 31b Cylinder 31 Cradle roll for winding 32 Coil forming roll 30a, 31a, 32a Shaft attachment part 33 Clade Luroll 33a Fixing stand 34 Bending roll 35 Coil movement locus 36 Pinch roll 37 Leveling roll 38 Bar joining device 41 Joining device main structure 42 Bottom plate 43 Joining device part 44 Lifting table 44a Lifting guide roll 51 Slab (seat bar) 51a Hot water surface 52 Guide Roll 53 Pinch roll 54 Plate cutting device 56 Finishing rolling machine 57 Cooling runout table 58 Winding machine

Claims (6)

[Claims] 1. A hot rolling line having a continuous casting machine for continuously forming and discharging a slab, and a finishing rolling machine provided at a subsequent stage of the continuous casting machine, wherein the continuous casting machine is used to form a sheet width during casting. And a belt type continuous casting machine having a mechanism capable of changing, between the belt type continuous casting machine and the finish rolling machine, an inline rolling machine is provided, and the belt type continuous casting machine and the finish rolling machine are further provided. A hot rolling line characterized in that a coil box for coil holding, heating, and storage is provided between the machine and the latter stage of the in-line rolling machine. 2. The hot rolling line according to claim 1, wherein the slab discharge port of the belt type continuous casting machine is continuously provided with a non-solidification reduction device. 3. The hot rolling line according to claim 2, wherein a plate edge heating device is provided at an inlet portion of the inline rolling mill. 4. The hot rolling line according to claim 2, wherein an induction heating device is provided at the inlet of the inline rolling mill. 5. The hot rolling line according to claim 4, wherein the coil box is configured to allow plate bypass feeding. 6. The hot rolling line according to claim 5, wherein a sheet bar joining device is provided between the coil box and the inlet of the finish rolling mill.