JPS60244406A - Continuous hot rolling method - Google Patents

Abstract

PURPOSE:To join surely the end part of a rolling material during its running and to elevate the yield in continuous hot rolling by performing the descaling, oxidation prevention, overlapping of both end parts and press-contacting of the overlapping part on the end joining parts of the preceding and succeeding rolling materials between a rough rolling mill and finishing rolling mill. CONSTITUTION:The scheduled joining face of the rear end part of the preceding rolling material 2a and the scheduled joining face of the tip part of the succeeding rolling material 2b are mechanically descaled with an end part processing device 6 and the oxidation of the scheduled joining face is prevented by spraying a non-oxidizing gas from a nozzle 622 and also the tip part of the succeeding rolling material 2b is pushed up by a pushing-up device 8 and mounted on the rear end part of the preceding rolling material 2a at the place between a rough rolling mill 11 and finishing rolling mill 12 of a hot rolling line 1. The overlapping part of the rolling material is then allowed to contact with pressing by a roll press 7 and the rolling is performed continuously with a finishing rolling mill 12.

Description

Detailed Description of the Invention (a) Field of Industrial Application The present invention relates to a method for continuously joining the ends of a rolled material between a rough rolling mill and a finishing mill in a hot rolling line. .

(B) Prior Art In conventional hot rolling, heated slabs are fed one by one to a rolling line, and each slab is subjected to intermittent rolling in a rough rolling mill and a finishing mill. With this method, when the rolled material passes through the rolling mill, the leading end of the material may hit the guide roll, and when the trailing end passes through the rolling mill, it may be squeezed due to the shape of the trailing end and the rolling conditions. However, problems such as roll damage often occurred. In order to avoid such troubles, it is necessary to take measures such as lowering the rolling speed, and once a trouble occurs, the downtime of the line will increase, leading to an increase in the roll cost unit. Become.

Compared to the center, the front and rear ends of a rolled material are more prone to temperature drop and thickness deviation due to imbalance in rolling speed (also, the center of the width protrudes in the rolling direction and becomes narrower, making it difficult to maintain the specified sheet width). In addition, the width of the tip of the rolled material became narrow due to the sudden rise in tension immediately after the work rolls of each stand of the finishing mill were bitten, making it difficult to obtain the desired width. There were times when I couldn't do it.

Therefore, in recent years, as a method to solve these problems, continuous rolling has been developed by overlapping the rear end of the preceding rolled material and the leading end of the following rolling material on the exit side of the rough rolling mill, joining the rolled materials to each other. ○ For example, in Japanese Patent Publication No. 54-39195, a method is proposed in which rolled materials are superimposed and then crimped and joined using a press with a flat tool.
A method of continuous rolling has been proposed. Tokuko Showa 54-3
Publication No. 9194 describes a method in which rolled materials are superimposed, their side surfaces are joined by tack welding, and the materials are rolled down using a finishing mill. Japanese Patent Publication No. 5'6-45712 discloses a rotary press device as a pressure bonding device for overlapping portions, which achieves bonding by a crimping body provided on a rotating drum. In Japanese Patent Publication No. 58-7398, Nα is applied to the joint.
A method has been proposed in which a powder containing oxides of B and B as essential components is applied, and the rolled materials are superposed and then pressure welded.

However, these conventional techniques have drawbacks in terms of equipment, reliability of bonding, and bonding strength, and do not provide a bonding method that is fully satisfactory in actual production lines.

The above-mentioned Japanese Patent Publication No. 54-39194, Special Publication No. 54-
In the method described in Japanese Patent No. 39195, it is necessary to control the running of a heavy press or welding machine in synchronization with the rolling material, and there are many problems in applying it to an actual production line.

Furthermore, one of the major problems regarding joining of rolled materials is the scale present on the surface of the rolled materials. How to prevent the occurrence of this scale is an important issue in bonding. Japanese Patent Publication No. 54-39195 proposes a method of stacking rolled materials after high-pressure water descaling and then press-welding them.

However, with this method, scale is generated even after descaling and before press welding, and it is not possible to obtain a sufficiently satisfactory bonding strength with this method.

The composition of the powder disclosed in Japanese Patent Publication No. 58-7398 has a rolling material temperature of about 1000°C, has extremely low viscosity, has good fluidity, has a thin film, and dissolves existing scale. In addition, the coating is more likely to break due to contact with the conveying table, leading to the formation of scale, making it impossible to obtain a sufficiently satisfactory bonding strength.

In the method described in Japanese Patent Publication No. 54-391.95, the joint surfaces of rolled materials are overlapped and the side surfaces are tack welded, so the joint area occupied by the entire joint surface is small and the joint strength is low. The method described in Japanese Patent Publication No. 56-45712 has the disadvantage that it is weak and creates a step between the joint and non-joint parts, and is easily broken in the finishing mill due to sudden load fluctuations when the finishing mill inserts. , the overlapping part must be joined in an extremely narrow part of the drum called the crimping body, and on the other hand, the running speed of the rolled material is constantly fluctuating, making it extremely difficult to control the rotation of the drum and causing problems due to slight disturbances in synchronization. There is a risk that it will not be possible to join, or that there will be bumps due to poor biting, which poses problems when used as actual production equipment.

←Problems to be Solved by the Invention The problems to be solved by the present invention are to provide a continuous hot rolling method that easily and reliably joins the ends of rolled materials, reduces rolling troubles, and provides a high yield. The purpose is to obtain a rolling method.

B.) Means for Solving the Problems The continuous hot rolling method of the present invention is characterized in that between a rough rolling mill and a finishing mill of a hot rolling line, the trailing end of the preceding rolled material is Mechanical descaling treatment is performed on the tip of the trailing rolled material and the surface to be joined. After descaling the rolled material, a nozzle is provided in the passage of the surface to be joined up to the crimp joint, and the nozzle is used to descale the surface to be joined from the nozzle. The above problems are solved by spraying an oxidizing gas, overlapping the surfaces to be joined, and pressing and joining the overlapping parts with a roll press, and performing all of the above steps while the rolled material is running. ing.

(E) Example FIG. 1 is a schematic explanatory diagram of a hot rolling line in which the method of the present invention is carried out. The method of the invention is carried out between the exit side of the roughing mill 11 and the entry side of the finishing mill 12 of the hot rolling line 1 .

The rolled material 2 (0 in FIG. 1, where the preceding rolled material is 2α and the subsequent rolled material is 2h) is sent by a conveyance table 3. The conveyance speed of the rolled material 2 is controlled by one pinch roll 4. Cropped portions at the front and rear ends of the rolled material 2 are cut and removed by a shear 5.

An end treatment device 6 is disposed on the outlet side of the pinch roll 4, a roll press 7 is disposed on the inlet side of the finishing rolling mill 120, and a push-up device 8 is disposed between them.

The end treatment device 6 includes a descaler 61 and a gas blowing device i62.
Consisting of The descaler 61 is comprised of a grinder, a rotating cutting tool, or the like, and mechanically cuts the surfaces to be joined at the front and rear ends of the rolled material 2 to remove scale. The gas blowing device 62 is
It consists of a header 621 and a nozzle 622 installed above and below the rolled material 2, and is installed over the entire length from the exit side of the descaler 61 to the entrance side of the roll press 7. The gas blowing device 62 sprays non-oxidizing gas from a nozzle 622 onto the surface to be joined of the rolled material 2 after the descaling treatment to prevent oxidation of the surface to be joined. In other words, the non-oxidizing gas blown out from the nozzle 622 is
, 2h, the area near each scheduled bonding surface is maintained in a non-oxidizing atmosphere. As the non-oxidizing gas, argon gas, nitrogen gas, etc. are preferable.

It is also possible to divide the header 621 of the gas blowing device 62 into a plurality of zones in the longitudinal direction of the line, and control the blowing and stopping of gas for each zone in synchronization with the traveling of the surface to be joined.

The push-up device 8 pushes up the leading end of the trailing rolled material 2h onto the conveyance line by a predetermined height, and
Any device may be used as long as it has a function of being lowered so as to be placed on the rear end of α. For example, it may be of a mechanism in which a plurality of conveyor rollers are raised and lowered separately or integrally by a fluid pressure cylinder or the like.

Since the pinch roll 4 can control the traveling speed of the trailing rolled material 275, the surface to be joined at the leading end of the trailing rolled material 2h is accurately aligned with the surface to be joined at the rear end of the preceding rolled material 2α. 0 The roll press 7 is capable of raising and lowering rotationally driven rolls at a constant cycle, and has the function of crimping the overlapping portions of rolled materials as they descend. That's fine.

For example, as shown in FIGS. 2 and 3, the roll press 7 includes a pair of upper and lower work rolls 72 in a frame 71. The chock 73, which rotatably supports the upper roll 72, is made movable up and down, and the driving force from the drive motor 740 is transferred to a gear 742 coaxial with the flywheel 741, and a main chock 73 that meshes with this gear 742. - Power is transmitted to a crank 75 by a power transmission mechanism 74 comprising a gear 743, and the upper roll 72 is moved up and down by a crank mechanism centered around the crank 75.

The principle of the crank mechanism for raising and lowering the roll chock 73 is shown in FIG. An intermediate member 76 having a substantially triangular shape is connected to an eccentric shaft 751 of the crank 75 that rotates together with the main gear 743. One end of a swing link 77 and one end of a connecting rod 78 are pivotally attached to the intermediate member 76 at separate and distant positions. The other end of the swing link 77 is pivotally fixed to the frame 71, and the connecting rod 78
The other end is a joint that is pivotally connected to the connection point of a joint link 79 that suspends the roll chock 73.
The link 79 consists of an upper link 791 and a lower link 792. The upper end of the upper link 791 is swingably fixed to a part P of the frame 710, and a roll chock 73 is pivotally connected to the lower end of the lower link 792. are doing. The upper and lower links 791 and 792 are pivotally connected at approximately the midpoint of their total length, and when this pivot point is pushed and bent by the connecting rod 78, the hanging length changes and roll chocks are created. The position 73 can be moved up and down.

When the overlapping of the ends of the rolled material is completed, the leading rolled material 2α and the trailing rolled material 2h are controlled at a constant speed, and the overlapping portion is guided to the roll press 7. Upper and lower rolls 72 of roll press 7, 7. -2 rotates at a speed synchronized with the running speed of the rolling month. In response to the overlapping completion signal, the upper roll starts descending, and a certain amount of pressure is applied to the overlapping portion between the upper and lower rolls.

The upper and lower rolls 72, 72 may be driven and rotated by spindles only when applying pressure, or may be driven to rotate at all times. In response to the overlapping completion signal, the clutch is engaged, the drive shaft is rotated, and the main gear 74 is rotated.
3 to rotate the crank 75, and the upper roll 72 starts to descend by the link mechanism. Since bonding is performed intermittently, the flywheel is configured to generate a large amount of energy during crimping. When the crimping is completed and the upper roll 72 begins to rise, the brake is activated in response to the signal, and the upper roll 72 stops at a height that allows it to maintain an appropriate distance from the lower roll 72.

The upper roll 72 waits at that position in preparation for the next joining,
Again in response to the superposition completion signal, the upper roll begins to descend and the cycle described above is repeated.

Pinch roll 4, end treatment device 6, roll press 7
The operation timing of the push-up device 8 is determined by detecting the position and speed of the rolled material from time to time using a position detector, speed meter, etc.
The detection signal is sent to a control device with a built-in computer, which predicts each position of the rolled material after a predetermined period of time, and sends operation timing and operation control signals to devices at each corresponding position.

The rolled material 2 whose ends have been joined is continuously rolled by a finishing mill 12, and after the joint is cut again by a shear 9, it is wound onto a take-up reel 10. Although the joint part does not necessarily have a uniform thickness, the deviation in thickness can be reduced by appropriately selecting the roll diameter and rolling reduction settings of the upper and lower rolls, so there is no problem with rolling with the current finishing mill 12. do not have.

In order to ensure the overlapping of the ends of the rolled material, it is also effective to form one of the ends of the rolled material in advance in the opposite direction.

(f) Effects According to the present invention, it is possible to prevent the occurrence of scale on the joining surfaces of rolled materials in a simple and reliable manner, and it is possible to join rolled materials together using a roll press, and the joint strength is high enough to withstand finish rolling. is obtained. Furthermore, in the roll press, it is possible to adjust the biting angle β shown in FIG. 5, and troubles such as bumps at the start of rolling can be easily prevented. Even if the timing of the start of lowering of the upper roll is slightly shifted, there is no problem in joining as long as the biting angle β is slightly shifted, and this method is extremely flexible from the viewpoint of controllability.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a hot rolling line that implements the method of the present invention. FIG. 2 is a side view of a roll press used in the method of the present invention. Figure 3 is a front view seen from the line ■-■ in Figure 2. FIG. 4 is a schematic diagram showing the operating principle of the press. Figure 5 is an explanatory diagram showing the penetration angle of the rolls in a roll press 01: Hot rolling line 2: Rolled material 2α; Leading rolled material 2h: Following rolled material 3: Conveying table 4: Pinch roll 5: Sha 6:
End treatment device 7: Roll press 8: Push-up device 9: Sha 1o: Take-up reel 11: Rough rolling mill 12: Finishing rolling machine Patent applicant Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] Between a rough rolling mill and a finishing mill of a hot rolling line, performing mechanical descaling treatment on a surface to be joined at the rear end of the preceding rolled material and a surface to be joined at the leading end of the subsequent rolled material;
After descaling the rolled material, a nozzle is provided in a passage area of the surfaces to be joined up to the crimp joint, and a non-oxidizing gas is sprayed from the nozzle onto the surfaces to be joined, and the surfaces to be joined are overlapped with each other. A continuous hot rolling method comprising: joining the overlapping portions by pressure bonding using a roll press; and performing all of the above steps while the rolled material is running.