JPH04105701A - Method and equipment for continuous hot rolling of thin sheet - Google Patents

Abstract

PURPOSE:To perform continuous rolling with a smaller number of rough rolling mills by selecting whether joining is conducted in the state of a slab before rough rolling or in the state of a bar material after rough rolling in accordance with the kind of steel of rolled stock and then rolling the material. CONSTITUTION:Since joining machines 4, 8 are mounted on the respective inlet sides of a group 5 of rough rolling mills and a group 10 of finish rolling mills, joining can be conducted in the state of a bar material after the rough rolling and joining is conducted in the state of a slab before the rough rolling in case of special steel centering SUS. Consequently, the rough rolling can be conducted by using one rolling mill R1 reversibly, special steel can be rolled by three common rolling mills R1-R3 and the finish rolling can be conducted continuously. In other words, continuous rolling can be conducted by less number of mills in the rough rolling.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and equipment for continuous hot rolling of thin sheets, and in particular, to manufacturing thin sheet products by sequentially joining rolled materials and continuously hot rolling them. The present invention relates to a rolling method and equipment for rolling.

[Conventional technology]

In hot rolling, when the sheet thickness becomes thinner, the leading and trailing edges of the thin sheet become more curved, and accidents at narrowing become more likely to occur. To prevent this, it is desirable to roll the rolled material endlessly and continuously. In order to continuously hot-roll rolled materials, it is necessary to sequentially join the rolled materials. Regarding joining methods of rolled materials, a method of joining in the state of slabs before rough rolling is disclosed in JP-A-57-106403, and a method of joining in the state of bar materials after rough-rolling is described in JP-A-58-112601. Disclosed in the official gazette. In the former, two planetary mills are arranged as rough rolling mills to enable continuous rough rolling of the joined slabs.

In the latter method, a roughly rolled bar material is wound into a coil, then unwound and joined to the previously rolled material.

On the other hand, it is preferable to process both ordinary steel and special steel such as stainless steel in one hot rolling line from the economical point of view of the equipment. The publication states that roller guide type continuous casting equipment and rotating belt type continuous casting equipment are installed side by side on the same hot rolling line, and special steel is manufactured using the roller guide type continuous casting equipment and ordinary steel is manufactured using the rotating belt type continuous casting equipment. death,
Each is supplied to a downstream rolling line.

[Problem to be solved by the invention]

Continuous hot rolling of thin sheets by joining rolled materials is described in Japanese Patent Application Laid-Open No. 57-
As shown in Publication No. 106403, the method of sequentially joining the rolled material in the state of the slab before rough rolling allows the rolled material to be continuously sent to all the rolling mills, including the rough rolling mill and the finishing rolling mill. In that sense, this is the most ideal method. However, rough rolling is done at a low speed, and from a plate thickness of around 250W,
A large amount of rolling, down to about 0 mm, must be carried out.

This rolling can be done relatively easily when the material to be rolled is ordinary steel, but when the material to be rolled is special steel, mainly stainless steel, the deformation resistance and seizure are large, so rolling with an ordinary roughing mill is not possible. It is difficult. For this reason, JP-A-57-106
As described in Japanese Patent No. 403, there is a problem in that a special and complicated rolling mill capable of rolling with a large reduction amount, that is, two planetary mills, must be installed as a rough rolling mill.

On the other hand, the method of joining the bar materials after rough rolling, as described in JP-A No. 58-112601, involves the above-mentioned problems because the rough rolling is carried out in a normal rough rolling mill as in the past. does not occur. However, when rolling slab materials, fishtail or tongue-shaped defects generally occur at the front and rear ends of the slab, but in JP-A-58-112601, consideration is given to changing the joining position of the rolled materials depending on the steel type. Even if the rolled material is ordinary steel, it will be joined in the state of the bar material after rough rolling, so the rough rolling will be the conventional rolling of slab material, resulting in the above-mentioned defective parts and slow progress. There is a problem in that it causes a drop in retention. In addition, scale is easily generated in ordinary steel, so when the bar material after rough rolling is wound into a coil, the scale generated on the surface is wound and eaten into the base material during the unwinding operation, resulting in poor surface quality of the rolled product. The problem is that it worsens the

Furthermore, JP-A-57-149007 and JP-A-57
- In Publication No. 149008, continuous casting equipment is designed to select a method suitable for either ordinary steel or special steel, and supply the manufactured slabs to the downstream rolling line. There is a problem that no bonding is performed and continuous hot rolling cannot be performed.

The purpose of the present invention is to minimize the decrease in yield during rough rolling by changing the joining position of rolled materials depending on the steel type, without requiring a special and complicated rolling mill, and to achieve high quality for various steel types. An object of the present invention is to provide a continuous hot thin plate rolling method and equipment capable of manufacturing thin plate products.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a continuous hot thin plate rolling method for manufacturing thin plate products by sequentially joining rolled materials and continuously hot rolling the rough rolling according to the steel type of the rolled material. Select whether to join the rolled materials in the state of the previous slab or the state of the bar material after rough rolling, join the rolled materials according to the selection, and perform hot rolling continuously. .

For example, when the rolled material is ordinary steel, it is joined in the form of a slab, and when it is made of special steel, mainly stainless steel, it is joined in the state of a bar material.

Here, preferably, when joining the rolled materials in the state of a bar material, the roughly rolled bar material is wound into a -H coil, and then this is unwound to perform the joining. Rough rolling of the slab when joining the rolled material in the state of a bar material includes a step of performing reversible rolling with at least one rolling mill.

More preferably, the joining of the rolled materials is performed by butting the rear end of the preceding rolled material and the leading end of the subsequent rolling material with a gap, applying a solvent to the abutting surfaces of the two in this state with cutting gas, and then crimping the solvent part. Do by doing.

Preferably, the slab is manufactured on a continuous casting line, and preforming is performed to concave the front and rear ends of the slab during the manufacturing process.

In addition, in order to achieve the above object, the present invention provides a continuous hot sheet rolling facility for manufacturing thin sheet products by sequentially joining rolled materials and continuously hot rolling them, with a rough rolling facility and a finishing rolling facility. , and a rolling material joining device disposed on the entry side of the rough rolling equipment and on the entry side of the finish rolling equipment, respectively.

Preferably, a coil winding and unwinding device for winding and unwinding the roughly rolled bar material into a coil is installed on the outlet side of the rough rolling equipment.

Preferably, the rough rolling equipment includes a plurality of rough rolling mills, at least one of which is a rolling mill capable of reversible rolling.

[Effect]

In the present invention, depending on the steel type of the rolled materials, it is selected whether to join the rolled materials in the slab state before rough rolling or in the bar material state after rough rolling. For example, when the rolled material is ordinary steel, it is joined in the form of a slab, and when it is made of special steel, mainly stainless steel, it is joined in the state of bar material.

There are differences in physical properties between ordinary steel and stainless steel, as shown in the table in Figure 7. That is, stainless steel (abbreviated as SUS)
Compared to ordinary steel, steel has the disadvantages of greater resistance to deformation, and greater resistance to smoked wood with rolls, but it has the characteristic that scale does not easily form.

The deformation resistance of SUS is approximately 1.5 times greater than that of ordinary steel. In addition, in SUS material, N is called 5US304.
Many SUS materials contain i, but when such materials are subjected to high pressure reduction, the Ni component of the SUS material causes seizure with the rolling rolls. For this reason, in rough rolling of ordinary steel, for example, from a slab thickness of 220 mm, in the first pass, 12 mm is close to the slip limit.
Seizure with the roll does not occur even if the pressure is reduced to about 0.
For US materials, the reduction amount is limited to about 40 mm. In the end, for rough rolling from a slab with a thickness of 220mm to a bar material with a thickness of around 30mm, about 3 passes are sufficient for ordinary steel, but about 5 passes are required for SUS material (see Figure 6).

Therefore, if the SUS materials are joined in the form of slabs, five rolling mills are required for rough rolling in the above example, which is economically disadvantageous. That is, the production amount of SUS material is generally 5 to 10% of that of ordinary steel, and it is not economical to arrange a large number of rolling mills for rough rolling of such a small number of rolled materials.

In the present invention, since special steels such as stainless steel are joined in the form of bar materials, rough rolling can be performed in the conventional slab state, and rough rolling is performed by reversible rolling using at least one rolling mill. Is possible. Therefore, even if the number of rough rolling mills is the same as that required for rolling ordinary steel, rough rolling can be performed without using a special rolling mill, and subsequent finish rolling can be performed continuously. That is, continuous rolling is possible with a reduced number of rough rolling mills.

Further, in joining the bar materials, since joining requires about 30 seconds, there is a problem that the bar materials cool down during that time.

However, since SUS material does not easily form scale, it is possible to wind it into a coil for heat retention, and then unwind the tip and join it to the tail end of the preceding bar material. It is possible to join materials. That is, SUS
The material allows joining of bar materials with less temperature drop and without deteriorating surface quality. In addition, by once winding it into a coil, continuous rolling with a reduced distance between rough rolling and finishing rolling becomes possible.

On the other hand, ordinary steel can be rolled in a large amount at one time, so even if the number of rolling mills is reduced, it is possible to perform continuous rough rolling with joining in the form of slabs. In addition, by performing such continuous rough rolling, the occurrence of fishtails and tongue-shaped defects at the front and rear ends of the slab, which are seen in conventional slab rolling, is prevented, and the yield loss during rough rolling is minimized. can be kept to a limit.

Further, since ordinary steel has the disadvantage that scale is more likely to occur than SUS material, heat retention by winding the bar material into a coil is not preferable in terms of scale digging into the base material. In the present invention, ordinary steel is rough-rolled into bar material and then continuously finish-rolled, so that the occurrence of scale is minimized.
A thin plate product with good surface quality can be obtained.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

In FIG. 1, the continuous hot thin plate rolling equipment of this embodiment includes a continuous casting machine 1, a slab press and cutting device 2, a soaking furnace 3, a first joining device, that is, a slab joining machine 4, a rough Rolling mill group 5, coil winding and unwinding device 6, first shearing machine 7, second joining device, that is, bar material joining machine 8, first looper device 9, finishing rolling mill group 10, cooling device 11 , a second looper device 12, a second shearer 13, and a winder 14.15.

In the continuous casting machine 1, the continuous slab 14 is obtained by pouring the molten metal from the tundish 11 into the mold 13 through the nozzle 12, and continuously cooling and shaping the molten metal. This continuous slab 14 is used in a press and cutting device 2 to facilitate joining in the slab state (if the rolled material is made of ordinary steel) or to improve engagement during rough rolling (if the rolled material is made of special steel). In order to form a recess at the end of the slab material (for example, in the case of stainless steel), the recess is formed and the slab 15 is cut.

Details of the press and cutting device 2 are shown in FIG.

In FIG. 2, the pressing operation is performed by pressing a press tool 17 with a cylinder 18 from both sides of the slab 14 using a press device 16. At this time, in order to perform pressing work in synchronization with the movement of the slab 14, the press device
6 is moved by a cylinder 19 in synchronization with the slab speed. After forming the recess 20 in this manner, the center portion of the recess 20 shown by the dotted line 21 in FIG. 2 is cut with the oxygen burner 23 of the gas cutting machine 22. This cutting is also performed by moving the cutting machine 22 using the cylinder 24 in synchronization with the slab speed. The cut slab becomes a slab 15 for rolling. Preformed recesses 25 are formed at the front and rear ends of the slab 15 manufactured in this manner. This preforming amount is 220m thick
In the case of m, it is advantageous for the next rough rolling to be approximately 120 mm.

This slab 1-5 is sent to a soaking furnace 3, and in the case of common steel, the soaked slab is joined by a slab joining machine 4 at the rear end of the preceding slab and the tip of the succeeding slab. Details of the joining machine 4 are shown in FIGS. 3 and 4.

In FIG. 3, a preceding slab 31 and a succeeding slab 32 are butted together with a gap g provided within a frame 30 of a joining machine 4. This gap g depends on the thickness of the slab, but is between 5 and
It is set to about 15 mm.

This setting is for the upper and lower rollers 34a, 35b, and 34b.

This is done using two stages of pinch rollers having 35b. That is, the position of the preceding slab 31 is set by driving the preceding pinch rollers 34b and 35b, and the position of the preceding slab 31 is set.
1, the succeeding slab 32 is sent in by driving the pinch rollers 34a and 35a at the latter stage, and the gap g is set. The upper rollers 34a and 34b of the pinch roller are raised and lowered by moving the arm 35 up and down by an actuator 36.

Two slabs 31.32 with gap g set in this way
are joined as follows. First, a cutting gas jet having a diameter d larger than the gap g is ejected from the solvent burner 37 to solvent the abutting surfaces of the rain sounds. This solvent makes the abutting surfaces clean and hot. Next, in this state, the pinch rollers 34a and 35a are driven to press the slab 32 against the slab 31 to press the solvent portion and complete the joining. In addition, at this time, the recess 25 is formed at the end of the slab as described above.
is formed, the bonding area becomes small and good bonding can be achieved in a short time.

During the above joining, the joining machine 4 is driven by the cylinder 38 on the rail 39 in synchronization with the speed of the preceding slab 31.

Figure 4 shows details of the solvent burner section. Oxygen is sent to the solvent burner 37 from a hose 40, and preheated gas is sent from a hose 41. Further, Fe powder is supplied from the hose 42 as needed. Hoses 40, 41 are connected to an oxygen pump 43 and a preheating gas cylinder 44, respectively. The hose 42 is connected to the Fe powder cylinder 45, and the cylinder 45
is connected to a pressurized gas pump 46.

As shown in FIG. 4, it is preferable that a large number of burners 37 be arranged in the width direction of the slab, and that these burners be arranged laterally along the abutting surfaces of the slabs. A motor 47 is provided for this purpose, and by driving the motor 47 a crank 48
Turn the connecting rod 49 in and out. The crank 48 is supported by a bearing 50. On the other hand, a large number of burners 37 are attached to the beam 51.
is coupled to a push/pull bar 52, which in turn is connected to the connecting rod 49. Further, the push/pull bar 52 is joined to a guide bar 53 as shown in FIG. 3, and this guide bar 53 is guided on the frame 30.

Returning to FIG. 1, the slab 31 joined by the joining machine 4 is rolled by the rough rolling mill group 5 to produce a bar material 60. The rough rolling mill group 5 consists of three rough rolling mills R1, R2, and R3. If the rolled material is ordinary steel, it subsequently passes through a coil winding and unwinding device 6 and a second joining device 8, and is sent to a finishing mill group 10 via a looper device 9. The finishing rolling mill group 10 includes three four-high rolling mills Fl, F2.
F3 and three 6-high rolling mills F4. F5. F6 is arranged in tandem.

The thin plate 61 rolled by the finish rolling mill group 10 is cooled by the cooling device 1.
1 to a predetermined temperature, the coil 62 is wound up by the winder 14 via the looper device 12, and the coil 62 is manufactured. When the diameter of the coil 62 reaches a predetermined value, the thin plate 61 is cut by the shearing machine 13, and the subsequent thin plate is wound up by the winding machine 15. At this time, it is preferable to cut the thin plate 61 and change the winding machine by slightly lowering the speed of the thin plate. In this case, in order to absorb the difference in rolling speed from the finishing rolling mill group 10, At this point, the speed of the pinch roller 63 is adjusted to release the looper 64.

The above is for ordinary steel, but if the rolled material is stainless steel,
That is, in the case of special steel, mainly SUS, the slab material is hot rolled as shown in FIG. 5 without being joined by the slab rolling mill 4.

That is, the slab 70 soaked in the soaking furnace 3 passes through the slab joining machine 4 and is directly sent to the rough rolling equipment 5. At this time, since the recess 25 is formed at the end of the slab as described above, the biting property is improved. In the rough rolling equipment 5, the first stage rough rolling mill R1 performs reversible rolling for a predetermined pass, for example, three passes, and then the rough rolling mills R2 and R3 perform rolling to produce the bar material 71. This bar material 71 is wound into a coil 72 by a coil winding and unwinding device 6. The wound coil 72 is sent to the unwinding side and becomes an unwinding coil 73,
It is rewound.

Winding of the coil 72 by the coil winding and unwinding device 6 is as follows:
Bend the three bar materials 71 upward with the benzone glow rough 4,
This is done by winding it up on a cradle roller 75. The position of the cradle roller 75 can be adjusted in the vertical direction by a cylinder 76.

Similarly, the coil 73 on the unwinding side is also rewound by a cradle roller 77 that is raised and lowered by a cylinder 76.

The tip end 79 of the bar material 78 obtained by unwinding the coil 73 is cut by the shearing machine 7, and is joined to the rear end 81 of the preceding bar material 80, which was cut by the shearing machine 7, by the bar material joining machine 8. The bar material joining machine 8 has the same configuration as the above-mentioned slab joining machine 4,
Joining is performed while moving in synchronization with the bar material 83 by the cylinder 38. In this case, there are no depressions at the front and rear ends of the rolled material.

The joined bar material passes through a looper device 9 and is rolled by a finishing mill group 10. At this time, since the moving speed of the welding machine 8 is slower than the rolling speed of the finishing rolling mill group 10, the speed difference is absorbed by adjusting the pinch roller 82 with the looper device 9 and releasing the loop 83, thereby making the work easier. It will be done.

The treatment after rolling in the finish rolling mill group 10 is the same as that for ordinary steel described above.

In addition, in the bonding machines 4 and 8, when these are not used, the upper pinch roller 34 shown in FIGS. 3 and 4
a, 34b move upward and open, and lower pinch rollers 35a, 35b function as table rollers for passing slabs or bar materials. Coil winding and unwinding device 6
Similarly, when not in use, that is, in the state shown in FIG. 1 in which ordinary steel is rolled, the bar material 60 is supported horizontally so as to function as a table roller for passing the bar material 60 through it.

FIG. 6 shows a typical rolling schedule for ordinary steel and SUS material according to the arrangement of this embodiment described above. In this example, in the case of ordinary steel, the slabs before rough rolling are joined by the joining machine 4, and rough rolling is performed from a slab with a thickness of 220 mm to a bar material with a thickness of about 30 mm in three passes R1 to R3. In particular, from a slab thickness of 220 mm, the slip limit is close to 1 on the first pass.
Reduce the pressure by about 20 degrees. On the other hand, in the case of SUS, the rough rolling does not involve joining the slabs, but performs 3 passes of reversible rolling in rolling mill R1, and 2 passes of rolling in rolling mills R2 and R3.
Rough rolling is performed from a slab with a thickness of 220 mm to a bar material with a thickness of about 30 W in a total of 5 passes. In particular, the amount of reduction in each pass is limited to 40- or less. This is because, as mentioned above, SUS has greater deformation resistance and seizure resistance than ordinary steel. In the case of SUS, after rough rolling, the bar material is joined and finish rolling is performed continuously.

Through the above-described joint continuous rolling, ordinary steel can be rolled to a thickness of 1.
6) Thin plates of 2.0 m are manufactured using SUS material.

As described above, according to this embodiment, since the welding machines 4 and 8 are installed on the entry side of each of the rough rolling mill group 5 and the finishing rolling mill group 10, in the case of special steel mainly made of SUS, Bonding can be performed in the rolled bar state, and rough rolling can be performed in the slab state, which is the reverse of the conventional method. For this reason, rough rolling can be performed using one rolling mill R1 in a reversible manner, and special steel can also be rolled with the three ordinary rolling mills R1 to R3 required for rough rolling of ordinary steel. Rolling can be performed continuously.

That is, continuous rolling can be performed with a reduced number of rough rolling mills.

In addition, since SUS material is difficult to form scale, the roughly rolled bar material can be wound around a coil 72 for heat retention, and its tip can be unwound and joined to the tail end of the preceding bar material. Bonding of materials can be carried out with less temperature drop and without deteriorating surface quality. In addition, by once winding it into a coil, continuous rolling with a reduced distance between rough rolling and finishing rolling becomes possible.

On the other hand, ordinary steel can be rolled in a large amount at one time, so even if there are three rough rolling mills R1 to R3, it is possible to join the slabs before rough rolling and perform continuous rough rolling. Also,
Continuous rough rolling prevents the occurrence of fishtails and tongue-shaped defects at the front and rear ends of the slab that are seen in conventional slab rolling, and minimizes the yield loss during rough rolling. can.

Furthermore, although common steel has the disadvantage that scaling is more likely to occur than SUS material, the bar material after rough rolling is continuously finish rolled without being wound into a coil.

For this reason, the scale digging into the base material that occurs when coiling the bar material does not occur, and a thin plate product with good surface quality can be obtained.

In the above example equipment, the specifications of the main products manufactured are as follows.

As ordinary steel, low carbon steel, medium carbon steel, etc. can be rolled, and as special steel, SUS material, high carbon steel, high tensile strength steel, Si steel, etc. can be applied. The thickness of the slab can be selected appropriately, usually between 300 and 120 mm, and the width of the slab is between 700 and 2000 mm.

The temperature of the slab after leaving the soaking furnace is around 1200°C, 1100-1000°C for bar material, 800°C after finishing rolling.
~920°C, and winding is 550~780°C
It is done to a certain degree. The thickness of thin plate products is 1.0 to 12.5m.
m, and the maximum rolling speed immediately after finish rolling is approximately 1200 m.
m/min.

In addition, in the above embodiment, a recess 2 is formed at the front and rear ends of the slab 15.
5 was preformed, but of course, depending on the condition of the thickness of the slab, it may not be necessary to perform the press treatment for concave preforming. However, when this preforming is performed as described above, there is an effect that the joining area of the slab is reduced and joining is facilitated, or that the biting property in the rough rolling mill is improved.

Further, in the above embodiment, the number of rough rolling mills is three and the number of finishing rolling mills is six, but each of these may be increased or decreased by one or two.

In addition, in the above examples, the SUS material was roughly rolled and then wound around a coil and joined together, but the SUS material was directly fed into a joining machine without being wound up, and the end of the bar material coming out of the rough rolling machine and the tail of the preceding bar material were used. The ends may be joined. However, when winding into a coil, the bar material can be prevented from cooling during the joining time as described above, and the distance between the rough rolling mill and the finishing mill can be shortened.

Further, in the above embodiments, the joining method was described as joining by pressure bonding after a solvent using a gas jet on the abutting surfaces, but of course, various other methods such as well-known flash butt, resistance welding, etc. can be applied.

〔Effect of the invention〕

According to the present invention, rolling is performed by selecting whether to join the rolled material in the slab state before rough rolling or in the bar state after rough rolling, depending on the steel type of the rolled material. Continuous rolling with a reduced number of rough rolling mills is possible without using a complicated rough rolling mill.

In addition, since continuous rough rolling can be performed when joining slabs, the occurrence of fishtails and tongue-shaped defects at the front and rear ends of the slabs is prevented, and the decrease in yield during rough rolling can be kept to a minimum. can.

In addition, when joining in the form of slabs, continuous rolling is performed from rough rolling to finish rolling, so ordinary steel, which is prone to scale, can be joined in the form of slabs and continuous rolling can be performed without damage caused by scale. When joining in this state, the bar material after rough rolling can be wound into a coil, so SU
By joining special steels mainly made of S material with bar materials, continuous rolling with less temperature drop is possible, and in both cases, thin plate products with good surface quality can be manufactured.

Furthermore, when joining the bar material, the bar material after rough rolling is once wound up into a coil, so continuous rolling can be performed with a reduced distance between the rough rolling mill and the finishing rolling mill.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the overall configuration of a continuous hot thin plate rolling equipment during slab joining according to an embodiment of the present invention, FIG. 2 is a final sectional view of a slab press and cutting device, and FIG. 3
4 is a detailed view of the solvent burner section of the welding device, and FIG. 5 is a schematic diagram showing the overall configuration of the equipment of this embodiment when joining bar materials, FIG. 6 is a diagram showing a typical rolling schedule of the equipment of this embodiment, and FIG. 7 is a diagram comparing the physical property values of common steel and stainless steel. Explanation of symbols 1... Continuous casting machine 2... Slab pressing and cutting device 4... Slab joining machine (joining device) 5... Rough rolling mill group 6... Coil winding and unwinding device total ... Bar material joining machine (joining device) R1 ... Rough rolling machine capable of reversible rolling

Claims (9)

[Claims] (1) Rolled materials are sequentially joined and hot rolled continuously,
In the continuous hot sheet rolling method for producing thin sheet products, it is selected whether to join the rolled materials in the slab state before rough rolling or in the bar state after rough rolling, depending on the steel type of the rolled material. , a continuous hot thin plate rolling method characterized in that the rolled materials are joined in the selected state and hot rolling is performed continuously. (2) In the continuous hot thin plate rolling method according to claim 1,
A continuous hot thin plate rolling method characterized in that when the rolled material is ordinary steel, the joining is performed in a slab state, and when the rolled material is special steel, mainly stainless steel, it is joined in the state of a bar material. (3) In the continuous hot thin plate rolling method according to claim 1,
A continuous hot thin plate rolling method characterized in that when joining rolled materials in the state of bar materials, the roughly rolled bar material is once wound into a coil, and then the coil is unwound to perform the joining. (4) In the continuous hot thin plate rolling method according to claim 1,
A continuous hot thin plate rolling method characterized in that rough rolling of a slab when joining rolled materials in the state of a bar material includes a step of performing reversible rolling in at least one rolling mill. (5) In the continuous hot thin plate rolling method according to claim 1,
The above-mentioned rolled materials are joined by butting the rear end of the preceding rolled material and the leading end of the subsequent rolling material with a gap, applying a solvent to the abutting surfaces of both in this state with cutting gas, and then crimping the solvent part. A continuous hot thin plate rolling method characterized by: (6) In the continuous hot thin plate rolling method according to claim 1,
A method for continuous hot thin plate rolling, characterized in that the slab is manufactured in a continuous casting line, and preforming is performed to concave the leading and trailing ends of the slab during the manufacturing process. (7) The rolled materials are sequentially joined and hot rolled continuously,
A continuous hot thin plate rolling facility for manufacturing thin plate products, comprising a rough rolling facility, a finishing rolling facility, and a joining device for rolled materials disposed at the entry side of the rough rolling facility and at the entry side of the finishing rolling facility, respectively. Continuous hot thin plate rolling equipment featuring: (8) In the continuous hot thin plate rolling equipment according to claim 7,
A continuous hot thin plate rolling facility characterized in that a coil winding and unwinding device for winding and unwinding the bar material after rough rolling into a coil is installed on the exit side of the rough rolling facility. (9) In the continuous hot thin plate rolling equipment according to claim 7,
The continuous hot thin plate rolling equipment is characterized in that the rough rolling equipment includes a plurality of rough rolling mills, at least one of which is a rolling mill capable of reversible rolling.