JP2002113509A - Endless hot rolling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breaking of a sheet and the damage of a press plate by securing weld strength and preventing the increase of roll load at endless rolling. SOLUTION: In a method by which sheet bars before finish rolling are joined and finish rolling is continuously performed, the thickness data of the sheet bar which are imparted to each sheet bar to be joined in the stage of an instruction set are compared in a group of joining sheet bars and all the thickness data of the sheet bars in the group are changed and unified into the thickness of the thinnest sheet bar.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless hot rolling method for continuously performing finish rolling, and more particularly to a rolling condition setting method.

[0002]

2. Description of the Related Art In a hot rolling process, conventionally, a slab is heated by a heating furnace, and the slab extracted from the heating furnace is roughly rolled, and then finish rolling is performed on each of the roughly rolled sheet bars. A rolling operation was being performed. However, in recent years, in order to manufacture steel strips such as thin ones, the joining (welding) of the tail end of the preceding (rolling target) material and the leading end of the following (rolling target) material is performed between the rough rolling mill and the finishing rolling mill. A so-called endless rolling operation, in which a preceding material and a following material are repeatedly finish-rolled continuously, is being performed.

[0003] However, in the hot rolling process, not all of the materials to be rolled are endlessly rolled, but the endless rolling operation is performed between batch rolling operations conventionally performed. Takes form.

[0004] Therefore, as a method for determining rolling conditions, a part of the method for determining rolling conditions in a conventional batch rolling operation is followed. That is, information on the type of material to be rolled (also referred to as a material to be rolled), specifications, dimensions, product thickness, product width, etc. is read, and rolling conditions for each material to be rolled are determined based on the information on the material to be rolled. It is determined in advance, then the rolling target material is supplied to a hot rolling line, and at various points in the hot rolling line, the entry of the rolling target material is detected, and when the entry of the rolling target material is detected, Based on the determined rolling conditions, set the operating conditions of the equipment downstream of the position where the entry of the material to be rolled is detected, thereafter, provide the material to be rolled to the equipment on the downstream side, and This is a method for determining rolling conditions, in which the downstream equipment is actually controlled under the operating conditions.

In the endless rolling operation, a process of joining each of the coarsely-rolled sheet bars at the front end and the tail end is required. As a prior art relating to this, as disclosed in Japanese Patent Application Laid-Open No. Hei 8-300008. There is technology. In addition to this, there is a technique proposed by the present applicant in Japanese Patent Application Laid-Open No. 7-24504.

The technique disclosed in Japanese Patent Application Laid-Open No. Hei 8-300008 discloses a laser welding apparatus in which one or both of a preceding clamping device and a following clamping device are provided with a vertical adjusting device for adjusting a vertical position of a joining surface. It is.

In the technique disclosed in Japanese Patent Application Laid-Open No. 7-24504, a tail end of a preceding sheet bar and a tip end of a following sheet bar are opposed to each other with a gap therebetween, and a coil conductor is provided from above and below the facing portion. A method of applying an alternating magnetic flux in the thickness direction of both plate materials, inducing an eddy current in the plate material, heating by Joule heat, and pressing and joining the opposing surfaces of the front end portion and the rear end portion, Claim 2 discloses a clamp device provided with a horizontal level holding mechanism having a pressing plate that sandwiches the sheet bar from one sheet bar to the other sheet bar.

Further, regarding this endless rolling technology,
As a prior art for setting rolling conditions, the present applicant has previously disclosed Japanese Patent Application Laid-Open Nos. 10-5830 and 11-16992.
No.6 and other technologies were proposed.

The technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 10-5830 discloses a technique for determining the joining order of rolled materials so that a thin material is located near the center of the unit when an endless unit is created. Is determined.

[0010] The technique disclosed in Japanese Patent Application Laid-Open No. 11-169926 is to roll the material to be rolled, which was originally scheduled to be subjected to endless rolling, by batch rolling when it becomes impossible to carry out endless rolling. , For batch rolling, and rolling conditions for both are determined in advance.

[0011]

However, according to the technique disclosed in Japanese Patent Application Laid-Open No. Hei 8-300008, one or both of the leading clamp device and the trailing clamp device are provided with an up and down position for adjusting the vertical position of the joining surface. Since an adjusting device is required, the mechanism is complicated. As shown in FIG. 1, when the succeeding sheet bar (the following material) 12 is thicker than the preceding sheet bar (the preceding material) 10, the joining portion 11 is formed. In the case where the sheet is first rolled by a finishing mill after the joining, the force from the upper and lower rolls 14 and 15 is applied to the steep corners of the sheet bar due to the step in the sheet bar thickness, as shown in the drawing. As a result, there is a problem that the joint 11 between the preceding sheet bar and the following sheet bar may be broken.

The technique disclosed in Japanese Patent Application Laid-Open No. 7-24504 discloses a clamp having a horizontal level holding mechanism having a holding plate for sandwiching a sheet bar from one sheet bar to the other sheet bar. Because of the use of equipment,
If the succeeding sheet bar is thinner than the preceding sheet bar,
As a result of holding both step portions by the holding plate, there is a problem that the holding plate is bent as shown in FIG. 2 and the joining operation cannot be performed thereafter. In FIG. 2, 1
Reference numerals 6 and 17 denote upper and lower clamps on the entrance side, and reference numerals 18 and 19 denote upper and lower clamps on the exit side.

In order to solve these problems, Japanese Patent Laid-Open No.
Techniques such as -5830 and JP-A-11-169926 are not sufficient, and there is room for improvement.

The present invention has been made to solve the above-mentioned conventional problems. In the endless rolling, the welding strength is secured, the roll load is prevented from increasing, and the breakage of the plate and the damage of the holding plate are prevented. That is the task.

[0015]

SUMMARY OF THE INVENTION The present invention reads rolling material information such as the type, standard, dimensions, product thickness and product width of a material to be rolled, and based on the rolling material information, determines in advance the material to be rolled. In the method of hot rolling according to the rolling conditions determined for each, in the case where the material to be rolled is a material to be rolled that is to be subjected to endless rolling in which the tail end of the preceding material and the leading end of the following material are joined and rolled, In the endless unit in which the rolling materials from the leading material to the final material of the rolling are arranged in the rolling order, the sheet bar thickness determined in advance as the rolling condition for each rolling material is compared, and the sheet is reduced to the minimum value among them. This problem has been solved by unifying the bar thickness and rolling.

In the present invention, the sheet bar thickness of the material to be rolled for performing the endless rolling operation is unified within the unit. Therefore, even when the succeeding sheet bar is thicker than the preceding sheet bar, it is possible to avoid a situation in which the force from the roll is applied to the sheet bar thickness difference corner and the joining is broken. In addition, it is possible to avoid a situation in which the holding plate is bent when the two step portions are sandwiched by the holding plate, and thereafter, the joining operation cannot be performed. Therefore, as shown in FIGS. 3A (in the state where the joining portion is engaged with the roll) and (B) (in the state where the joining portion is held down), smooth joining and finish rolling can be performed.

[0017]

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

FIG. 4 shows an outline of endless rolling. In this endless rolling operation, the tail end 10e of the preceding material 10
And the leading end 12t of the following material 12 are joined by a joining device 30 provided between, for example, three stands of the rough rolling mill 20 and, for example, seven stands of the finishing rolling mill 40, and the leading material 10 and the following material 12 are joined.
The finish rolling is continuously performed in a state where they are connected. On the downstream side of the finishing mill 40, a cutting machine 50 for the material to be rolled is installed. On the downstream side of the cutting machine 50, a plurality (2 in FIG.
Roll) 60 is installed, and the material to be rolled finish-rolled in a state in which the preceding material 10 and the following material 12 are connected to each other,
The cutting machine 50 cuts the rolled material into a length that can be wound by the winder 60, and winds the rolled material preceding the cutting point and the rolled material following the cutting point in separate windings. I'm going to do it with a machine.

In such an endless rolling operation, finish rolling can be performed continuously in a state where the preceding material 10 and the following material 12 are connected. There is no unsteady part at the tail end of the unit, and stable rolling can be performed over the entire length of the material to be rolled, and it is particularly suitable for rolling of a material to be rolled where it is difficult to pass unsteady parts such as thin materials. have.

The setting of the operating conditions of each facility in the hot rolling line is performed by a computer as shown in FIG. 5 as an example. That is, a person inputs information on attributes (slab steel type, standard, rolling dimensions, etc.) of each slab which is a material to be rolled from an order input device (terminal) 80 and gives it to a host computer 70 via, for example, an in-house LAN 82. The upper-level computer 70 sets rolling conditions (rolling temperature, rolling schedule, rolling speed, tension between stands, cooling conditions for the material to be rolled, etc.) as command values based on the information on the attributes of each slab, and sets the rolling conditions. To the lower-level computer 72.

When the slab is put into the rolling line, the lower-level computer 72 operates the detectors (the detector 24 at the exit of the rough rolling mill, the detector 32 at the exit of the joining device, The detection values (temperature, plate thickness, plate width, etc.) detected by the detector 44 on the exit side of the finish rolling mill, and the equipment (in FIG. 5, the rough rolling mill 20, the joining device 30, the finishing rolling mill 40, the cutting machine 50,
Rolled material information such as actual operation data of the winding machine 60 (rolling load in the rolling device 22 of the rough rolling mill 20 and the rolling device 42 of the finishing rolling machine 40) is read, and based on the rolled material information, The operating conditions of the facilities after the location where the material to be rolled is present are calculated so that the material to be rolled is rolled under the rolling conditions set by the host computer 70. Then, an operation condition signal based on the calculation result is sent to each facility, and each facility is operated.

For example, in the batch rolling operation, the calculation of the operating conditions of the finishing mill 40 by the lower computer 72 is performed at the stage where the rough rolling by the rough rolling machine 20 is completed, and Material information is detected by using the roughing rolling mill exit side detector 24 or obtained by calculation from actual operation data of the rough rolling mill 20, and based on the rolling material information, The operating conditions of the finishing mill 40 (rolling position of each stand, roll peripheral speed, etc.) are determined so that the finishing rolling is executed under the finishing rolling conditions sent from the computer 70.

On the other hand, in the endless rolling operation, after the joining of the preceding material 10 and the succeeding material 12 by the joining device 30 is completed, the lower computer 72 determines the operating conditions of the finishing mill 40 for the succeeding material 12. After the calculation, the operating conditions of the finishing mill 40 are determined so that the finishing rolling is executed under the finishing rolling conditions sent from the host computer 70, as in the case of the batch rolling described above.

FIG. 6 shows the overall procedure described above.

In the present invention, the sheet bar thickness determined in advance as a rolling condition for each material to be rolled is compared.
Roll the sheet bar thickness to the minimum value among them.

First, in order to determine in advance the sheet bar thickness as a rolling condition for each material to be rolled, the logic of the portion denoted by reference numeral 130 in FIG. 6 is determined, for example, as shown in FIG. That is, information on the attributes of each slab (slab steel type, standard, rolling dimensions (hot-press command thickness, hot-press command width, etc.)
May be determined by a logic such as indexing from a setting table stored and registered in advance in the host computer 70 as a key (these are also available for both endless rolling and batch rolling). preferable).

An input value to be previously input to the table as a set value of the sheet bar thickness is determined and input by a human in advance. In general, from the viewpoint of reducing the energy loss due to heat radiation and maintaining a high finishing rolling temperature to secure mechanical properties such as the strength and elongation of the material to be rolled after commercialization, the thicker the sheet bar, the better. It is preferable, however, that the thinner the finish thickness (heat-pressure command thickness) is, the more the thickness of the finish rolling mill must be reduced in order to prevent the load from increasing. In consideration of these various circumstances, a human determines and inputs in advance as described above.

At this time, the sheet bar thickness may be determined only for batch rolling, or may be determined for both batch rolling and endless rolling.

Now, if the number of rolling target materials of the endless unit is n and the sheet bar thickness is determined to be t1, t2,. For example, in the present invention, t in the endless unit
1, t2,... Tn, and the sheet bar thickness set value is rewritten to Min (t1, t2,... Tn) for all the rolling target materials in the endless unit. If the sheet bar thickness is determined only for batch rolling at the above-mentioned location, M
in (t1, t2,... tn) may be determined,
If the determination is made for both batch rolling and endless rolling, Min (t1, t
2,... Tn) may be determined.

As described above, the sheet bar thickness determined in advance as the rolling condition for each material to be rolled is compared, and the sheet bar thickness is unified to the minimum value among them.

[0031]

EXAMPLES As an example, Table 1 shows a specific example in which the sheet bar thickness for the endless rolling operation was actually determined when the sheet bar thickness was determined only for batch rolling.

[0032]

[Table 1]

Table 1 shows the rolled materials No. 6 of the same steel type (low carbon steel). 1 to 6 show an example in which sheet bars are joined on the entry side of a finishing rolling mill and finish rolling is continuously performed. In the conventional batch rolling, the sheet bar thickness is set for each material to be rolled, but in continuous rolling, the thickness is set to 30 mm which is the thinnest (fourth in the table).

[0034]

According to the present invention, the sheet bar thickness of the material to be rolled in the endless rolling operation is unified within the unit. Therefore, even when the succeeding sheet bar is thicker than the preceding sheet bar, the welding strength is secured, the roll load is prevented from increasing, and the force from the roll is applied to the sheet bar thickness difference corner so that the joint portion is formed. Can be avoided. Further, even when the succeeding sheet bar is thinner than the preceding sheet bar, when the step portions are sandwiched by the pressing plates, the pressing plates are bent, and thereafter, the joining operation cannot be performed. Things can be avoided. Therefore, FIG.
As shown in (1), smooth joining and finish rolling can be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a problem of the technology disclosed in Japanese Patent Application Laid-Open No. 8-300008.

FIG. 2 is a cross-sectional view for explaining a problem of the technology disclosed in Japanese Patent Application Laid-Open No. 7-24504.

FIG. 3 is a cross-sectional view for explaining the operation and effect of the present invention.

FIG. 4 is a front view showing an example of a hot rolling line to which the present invention is applied;

FIG. 5 is a block diagram showing an embodiment of a control device for implementing the present invention.

FIG. 6 is a flowchart showing a processing procedure of the embodiment.

FIG. 7 is a diagram showing an example of a record of a host computer used in the embodiment of the present invention;

[Description of Signs] 10: Leading material 12: Trailing material 20: Rough rolling machine 22, 42 ... Roll-down device 24, 32, 44 ... Detector 30 ... Joining device 40 ... Finishing rolling machine 50 ... Cutting machine 60 ... Winding Machine 70 Upper computer 72 Lower computer 80 Order input device

Continued on front page F-term (reference) 4E002 AD04 BC01 BD05 CA08 CA09 4E024 AA01 AA07 AA08 AA09 CC01 CC03 EE01

Claims (1)

[Claims] 1. The type, standard, dimensions, product thickness,
In a method of reading material information to be rolled such as a product width and performing hot rolling according to rolling conditions previously determined for each material to be rolled based on the material information to be rolled, the material to be rolled is a tail end of a preceding material and a trailing material. When the material to be rolled is to be subjected to endless rolling in which the ends of the materials are joined and rolled, in the endless unit in which the materials to be rolled from the leading material to the last material of the endless rolling are arranged in the rolling order, the material to be rolled is An endless hot rolling method comprising: comparing a predetermined sheet bar thickness as a rolling condition for each rolling condition; unifying the sheet bar thickness to a minimum value among them;