JPH0237801B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to continuous hot rolling equipment for continuously hot rolling.

(b) Prior Art In conventional hot rolling, heated slurps were fed one by one to the rolling line, and each slurp was subjected to intermittent rolling in a rough rolling mill and a finishing mill. In this method, when the rolled material passes through the rolling mill, the leading end of the material may hit the guide or roll, and when the trailing end passes through the rolling mill, it is narrowed down depending on the shape of the trailing end and the rolling conditions. This often caused problems such as roll damage. 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 consumption rate. Become.

The front and rear ends of a rolled material are more prone to temperature drop and thickness deviation due to unbalanced rolling speeds than the center, and the width center protrudes in the rolling direction and becomes narrower, making it difficult to maintain the specified sheet width. It was not obtained and was discarded. In addition, the width of a portion of the tip of the rolled material became narrow due to a sudden rise in tension immediately after the finishing work roll was bitten and during winding of the down coiler, making it impossible to obtain a predetermined width.

Therefore, in recent years, as a method to solve this problem, the rear end of the preceding rolled material and the leading end of the following rolled material are overlapped on the exit side of the rough rolling mill, and the side surfaces are tack welded. A method has been proposed in which rolled materials are joined together and continuously rolled. However, with this method, the joints of the rolled material are thicker than other parts, which causes sudden load changes to be applied to the next finishing mill.
Variations occur in plate thickness. In addition, the bonding force at the tacked portion was weak, leading to frequent rolling troubles.

(c) Purpose of the Invention The purpose of the present invention is to improve the rolling efficiency by smoothly and quickly joining the rear end of the preceding rolled material and the leading end of the trailing rolled material. Our objective is to provide type hot rolling equipment.

(d) Structure of the Invention The rolling equipment of the present invention incorporates a crank mill between a rough rolling mill and a finishing mill on a rolling line, and joins the ends of a preceding material and a succeeding material to each other. It is characterized by the fact that the crimp connection and rolling are carried out at the same time, thereby achieving a strong, uniformly thick, and quick bond.

The equipment configuration of the present invention will be specifically explained with reference to FIG. The apparatus of the present invention is installed along the rolling line between the last stand of the rough rolling mill 1 and the first stand of the finishing rolling mill 2, and includes as a main part a control device that operates the apparatus in a coordinated manner. .

First, a material detector 3 is installed at the most upstream position on the exit side of the rough rolling mill to detect passage of the tip of the rolled material and send a detection signal to the control section 9. On the downstream side adjacent to the material detector 3, there is a first measuring ring for detecting the feed rate of the material.
A roll (hereinafter referred to as MR) 4 is provided. This first MR 4 mainly detects the speed v ₁ of the trailing material S ₁ .

On the downstream side adjacent to the first MR4, there is a pinch
A role (hereinafter referred to as PR) 5 is provided. this
PR5 is a roll that changes the speed of the trailing material S ₁ according to each work process, and is a roll that changes the speed v 1 of the trailing material S ₁ detected by the first MR 4 and the speed v ₁ of the trailing material S 1 detected by the first MR 4. The control unit 9 commands an increased speed v ₁ ′, which is calculated based on the speed v ₂ of the preceding material S ₂ detected by the second MR 8 installed near the first stand. Increase the speed of row material _S1 . and,
At a predetermined joining position, the rear end (hereinafter referred to as the bottom) of the preceding member S ₂ is attached to the tip end (hereinafter referred to as the bottom) of the succeeding member S ₁
It's called Topp. ) can catch up with each other and overlap each other.

On the downstream side of PR5, there is a nose roll (hereinafter referred to as HR).
) 6 is provided. HR6 uses upper and lower rolls with different roll diameters to raise the top of the material upward by rolling.The upper roll has a small diameter and the upper and lower rolls are rolled at different speeds.
This speed difference includes zero, and the amount of nose raising,
That is, it is determined according to the nose-up height h and the nose-up length _l2 , and the control section 9 commands predetermined conditions.

A crank mill (hereinafter referred to as CM) is installed at the downstream joint position of HR6. CM7 performs strong crimping and rolling at the same time.
It is operated in synchronization with the timing when the bottom of S ₂ and the top of the trailing material S ₁ are superimposed on each other and introduced,
To reliably and quickly press-bond the ends of a material to each other, and to roll-form the material to the same thickness as the other parts. The timing of pressing down and the pushing force for crimping are commanded from the control unit 9.

Each roll constituting the equipment of the present invention is equipped with a roll rotation motor (hereinafter, suffix a is added).
and a motor for rolling down the roll (hereinafter, a subscript b is added), and all of the parts except the roll rotation motor 4a of the first MR4 and the roll rotation motor 8a of the second MR8 are used in the work process. The control unit 9 is controlled based on instructions from the control unit 9 in accordance with the above, and predetermined operations are performed in conjunction with each other.

Next, the operation of this device will be explained. As shown in FIG. 1, the front part of the preceding material S ₂ has already been bitten into the finishing mill 2, and the top of the succeeding material S ₁ is in the roughing mill 2.
When the trailing material S11 starts to come out, the material detector 3 first detects the passage of the top of the trailing material _S11 , and the controller 92
send a signal to. Here, the controller 92 first calculates the rough thickness obtained in advance from a host computer (not shown).
The first MR4 sets the roll gap commensurate with the commanded rough thickness and rolls the trailing material.
S with ₁ reach.

The first MR 4 starts measuring when the trailing material S ₁ comes into contact with it, inputs the velocity V ₁ of the trailing material to the microcomputer 91, and measures the time required for the top to reach the nose-up position. It is calculated by the microcomputer 91. At the same time, micro
The computer 91 receives the preceding material S ₂ from the second MR8.
The velocity of V ₂ is also being fed.

The microcomputer 91 calculates the velocity V 2 of the preceding material S ₂ , the velocity V ₁ of the following material S ₁ , the velocity V ₁ of the preceding material S ₂ and the succeeding material S ₁
Based on the distance l between the two materials, an acceleration speed v ₁ ' for the ends of the two materials to overlap immediately before the CM7 is calculated and commanded to the PR5 via the controller 92.

The distance l between the preceding material S ₂ and the succeeding material S ₁ is determined by the following method. The diameter R _A of the second measuring roll 8,
The rotation speed N _A is the elapsed time after the rear end of the preceding material S ₂ passes through the material detector 3 , and the elapsed time t _B is the elapsed time after the leading end of the succeeding material S ₁ passes through the rough rolling mill _{1 .} , rough rolling mill 1
When the work roll diameter R _B , the rotation speed N _B , and the distance between the rough rolling mill 1 and the detector 3 are L, the distance l between the rear end of the leading material S ₂ and the leading end of the trailing material S ₁ is , is expressed by the following equation.

l=πt _A ×R _A ×N _A +L−πt _B ×R _B ×N _BOn the other hand, apart from this, HR6 has a predetermined amount of nose raising.
hl ₂ is commanded from the controller 92, and the trailing material S ₁
As the top enters, a downward movement is performed to form a predetermined amount of nose elevation.

The trailing material S ₂ , whose top is molded upward, is PR5.
The material is transported at an increased speed V ₁ ', and it catches up with the preceding material near the entry side of the CM7, resulting in a state in which the ends are overlapped with each other. At this point, PR5 is commanded the original feed speed that has been decelerated by the increased speed, that is, the reference speed V ₂ ' synchronized with the preceding material S ₂ , and the two materials after overlapping are transferred to CM7 as if they were one piece. be introduced. On the other hand, in the CM7, a rolling command is issued from the control unit 9 at the timing when the overlapping part passes through the CM7, and the overlapping part is crimped by a preset pushing force and rolled at the same time.

In the pressure welding process of CM7, if this is just press pressure bonding, there is a risk that the pressure welded part will break in the downstream rolling process. Therefore,
In the present invention, the pressure contact surface is descaled immediately before pressure contact, and a non-oxidizing atmosphere is maintained after descaling until pressure contact is performed. As shown in Figure 2, a method to satisfy this condition is to
The process spanning from CM 6 to CM 7 is covered from the outside with a sealed chamber 10, and N ₂ ,
is supplied to form a non-oxidizing atmosphere, and the ends of the materials immediately before polymerization are descaled using a hot scarf or wire brush 11.

(E) Example 2, 270mm thick x 1600mm wide, extracted from a heating furnace
The slab (1250℃) is rolled into a 30mm thick rough rolling mill consisting of 6 stands on a normal rolling line.
After rolling down to a height of 1 mm, a light pressure reduction of 1 mm was applied using HR6 with a lower roll diameter of 500 mm and an upper roll diameter of 300 mm to obtain a nose raising amount h = 30 mm.

After that, the pressure contact surface was descaled over a total width of 50 mm using a wire brush that can be fed in synchronization with the material to be fed and can be moved freely. At this time, the temperature of each coarse bar was 950 to 1000°C. At this time, the leading material was being sent to the finishing mill at a rate of 0.75 m/sec, so PR5 was controlled in speed to catch up with the top of the following material, and the top of the following material was kept at 30 mm, and the weight was rolled at the position closest to CM7. Completed matching.

After that, PR until it reaches the lowering position of CM7.
The feed speeds of both materials are synchronized by the control in step 5, and the materials are transferred through a sealed chamber 10 with a non-oxidizing atmosphere in which N ₂ (2 kg/cm ² ) is press-fitted, and the materials are pressed together during running by CM 7. The thickness of the part was 30 mm. At this time, the pressure of CM7 is 22Kg/cm ² and the load is 1100ton.
It was hot.

When this rolled material was conventionally rolled in the final welding process, continuous pressure could be applied without causing breakage, and the hot rolling process to obtain a steel strip with a thickness of 2 mm and a width of 1600 mm could be completed.

(F) Effects Although the equipment of the present invention is relatively compact, it can join hot-rolled steel strips strongly and quickly, and there is no need to stop the line for joining. Extremely efficient. Furthermore, since the joint portion is not thicker than other portions, load fluctuations are not applied during the finish rolling process, and rolling troubles and variations in plate thickness do not occur.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram schematically showing the overall configuration of a continuous hot rolling facility according to the present invention. FIG. 2 is a partial view of FIG. 1 showing a configuration for forming a non-oxidizing atmosphere. 1: Roughing mill, 2: Finishing mill, 3: Material detector, 4, 8: Measuring roll (MR),
5: Pinch roll, 6: Nose up roll (HR),
7: Crank mill (CM), 9: Control section, 1
0: chamber, S ₁ : trailing rolled material, S ₂ : leading rolled material.

Claims (1)

[Claims] 1 Equipment installed between the final stand of the rough rolling mill and the finishing mill to join the bottom of the preceding rolled material and the top of the succeeding rolled material, which detects the top of the succeeding material and controls the detection signal. a first measuring roll that detects the speed v ₁ of the trailing material and inputs the speed to the control section; and a first measuring roll that detects the speed v ₂ of the preceding material and sends the detection signal to the control section. send second
and a nose raiser, which is arranged at the nose raiser position on the downstream side of the first measuring roll and rolls down the top of the trailing material to form a nose raise margin of a predetermined length based on a command from the control section. The speed of the trailing material is increased based on instructions from the controller so that the roll and the top of the trailing material, which has been formed nose-up, overlap the bottom of the leading material at a predetermined joining position.
v ₁ Keep it at ¹ , and after overlapping, use the standard speed after overlapping.
v ₂ A pinch roll placed between the first measuring roll and the nose raising roll, ^which is maintained at 1, and a pinch roll arranged at the joint position on the downstream side of the nose raising roll, are arranged at the timing when the leading material and the trailing material pass through the overlapping part. A crank mill that presses and rolls the overlapping portion with a pushing force based on a command from a controller, an accelerating speed v ₁ ′ at the time of overlapping with respect to the pinch roll, and a reference speed v ₂ after overlapping. ′ command, commands for the nose-up timing and reduction amount for the nose-up roll, and commands for the reduction timing and pushing force for the crank mill, as well as a control unit that coordinately issues commands for the crimping surface of both the front and rear materials at the position just before joining. Continuous hot rolling equipment for steel strips, which consists of a device that maintains a non-oxidizing atmosphere during the process of crimping and crimping.