JPS629704A - Hot rolling method - Google Patents

Abstract

PURPOSE:To compensate the temp. drop of a rolling material while satisfactorily maintaining heating efficiency by vertically moving induction heaters in synchronization with the vertical movement of detecting rolls and rolling a rolling material while maintaining the specified gap between the rolling material and heating inductor. CONSTITUTION:The tension detecting rollers 3, 4 in the starting state of sheet passage is positionally set at the same level as the pass line of rolling rolls 1a, 2a and the induction heaters 9, 10 are also set at the specified spacing with respect to the pass line. The front end of the rolling material S engages with the roll 2a from this state and thereafter a lifting solenoid valve 14 is operated by timer setting to start a synchronizing cylinder 13 to rise the rollers 3, 4 to a specified distance while the material S is maintained horizontal between said rollers. The heaters 9, 10 are raised in synchronization therewith while the spacing from the material S is maintained constant. Then the passability of the material S is assured and since the gap from the heating inductor is minimized, the high heating efficiency is obtd.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a hot rolling method, and more specifically, an induction heating device for heating a rolled material is arranged between stands of a finishing rolling mill to improve the heating efficiency. The present invention relates to a hot rolling method that can be utilized to its maximum potential.

(#Central Binjutsu) Hot stripping is usually done by heating a slab in a slab heating furnace.
It is manufactured by heating to a high temperature around 200°C, extracting it, and then rolling it up with a coiler through rough rolling and finishing rolling. However, even when a slab has a nearly uniform temperature distribution when it is extracted from a heating furnace, as rolling progresses, the temperature drops particularly at the middle end due to high-pressure water descaling, roll cooling water, natural cooling, etc. This results in non-uniformity of the material.

For this reason, a technique has been proposed for online heating compensation for the temperature drop, as disclosed in Japanese Patent Laid-Open No. 57-85601. Many induction heating methods have been proposed for this heating, and in order to increase heating efficiency, it is important to minimize the gap between the heating inductor and the rolled material in areas where the thickness of the par is thin.

In contrast, in conventional hot finishing rolling stands, there is a fourth
As shown in the figure, a looper roll 2o is installed and its arm is used to control the tension to be constant.
The threading level of rolled material between rolling mill stands varies greatly depending on the angle of the looper arm.

On the other hand, as seen in Japanese Patent Publication No. 59-5364, there is a looper-less tension control technology that calculates the inter-stand tension by back calculation from the torque of the mill motor without using a looper roll, and controls the speed to reach the standard tension. However, since it is a method that calculates and detects tension indirectly, each detection accuracy greatly affects tension control accuracy, and currently, except for rolled materials with relatively large cross-sectional areas, excessive tension (unity / ) tension 0.9 to 1,7 kg/am2), which has a negative impact on intermediate control accuracy, and causes fluctuations in loop height (±30 to 150 mm), resulting in problems with the threading level. It is hard to say that stability is sufficient.

(Problem to be solved by the invention) Therefore, in order to compensate for the temperature drop in the rolled material by arranging an induction heating device between the finishing pressure stands, it is necessary to eliminate the instability in the threading level of the rolled material. .

(Means for Solving the Problems) The present invention has been made to solve these problems, and its gist is to provide a vertically movable system between rolling mill stands that performs looperless tension control. Two tension detection rollers are installed, and an induction heating device that can move up and down in synchronization with the up and down movement of the detection rollers is arranged between the detection rollers, and the rolled material is held horizontally between the detection rollers,
This is a hot rolling method characterized by rolling while maintaining a constant gap with a heating inductor of an induction heating device.

(Function) In the above configuration, the two tension detection rollers arranged between the stands can maintain the horizontal level of the rolled material between them, and the tension between the stands can be maintained by the load cell or strain sensor installed on the detection rollers. By actually measuring the tension and controlling the tension with high precision through controlling the number of rotations of the rolling rolls based on the tension obtained by the measurement, rolling with extremely small fluctuations in the threading level is possible.

On the other hand, since the induction heating device, which is placed in the darkness of the tension detection roller and heats the rolled material, is moved up and down in synchronization with the up and down movement of the detection roller, the set gap between the rolled material and the heating inductor is can be kept constant at all times, making it possible to maintain good heating efficiency.

(Example) Next, an example of an apparatus suitable for carrying out the method of the present invention will be described. That is, FIGS. 1 to 3 are explanatory diagrams showing an example of an apparatus for implementing the method of the present invention, in which 1a is the Fl roll of a finishing mill, 2a is the F20-roll, and 3.4 is the Fl, F roll.
5.6 is a tension detection roller placed between two stands, and 7.8 is a tension detection type deno provided on each tension detection roller.
are fluid pressure cylinders that move the tension detection rows 23.4 up and down, respectively, and are connected to the synchronous cylinder 13.

Reference numeral 9.10 denotes an induction heating device that faces the upper and lower surfaces of the rolled material S in the tension detection roller 3.4i11, is connected to a fluid pressure cylinder 11.12, and is movable up and down. The fluid pressure cylinder 11.12 is connected to the tension detection row 23.
．． 4, fluid pressure cylinder 7,
The mechanism of the cylinder 13 is performed by operating the lifting solenoid valve 14 connected to the cylinder 13. Therefore, the tension detection row 23 .4 and the induction heating device 9.10 are configured to be able to rise and fall in synchronization with the operation of the synchronous cylinder 13.

In addition, in FIG. 2, illustrations of the synchronous cylinder 13, the lifting solenoid valve 14, and the piping to each cylinder 7, 8, 11, and 12 shown in FIG. 1 are omitted.

In such equipment, FIG. 1 shows the state where sheet threading has started, and the tension detection roller 3.4 is connected to the rolling rolls la, 2.
The induction heating device 9.10 is set at the same level as the pass line of a, and the induction heating device 9.10 is also set at a constant distance from the pass line. Therefore, since the gap between the inductor and the rolled material of the induction heating device 9.10 is still at a stage where tension control is not required, it is set to the minimum gap that will not cause contact between the rolled material and the inductor due to level fluctuations.

After the tip of the rolled material S is caught in the F20-rule 2a in this state, the lifting solenoid valve 14 is activated by the timer setting, the synchronous cylinder 13 is started, and the tension detection roller 3.4 is rolled between these rollers. The tension of the rolled material is detected by raising the material S by a certain amount while keeping it in a horizontal state and holding it at a certain angle.In addition, induction heating is performed in synchronization with the rise of the tension detection roller 3.4. ! 9.10 is also raised by the synchronous cylinder 13 while keeping the distance from the rolled material S constant at t.

After rising, the tension is controlled by tension detection, so the level fluctuation is small, and the gap is set even smaller to increase heating efficiency. Figure 2 shows the tension detection roller 3.4 and induction heating device 9.1.
0 is raised, and the operation is performed while maintaining a constant tension during rolling, the distance between the induction heating device 9.10 and the rolled material S is kept constant, and the tail end of the rolled material S is at the front stage stand 1. Just before passing through the tension detection roller 3.4 and the induction heating device 9.
10 is lowered by the synchronous cylinder 13 to the pass line position of the rolling rolls to ensure the sheet passing performance of the head of the next rolled material.

An example of tension control according to the present invention will be explained with reference to an example shown in FIG.

In the figure, at the same time as the tension detection roller 3.4 comes into contact with the rolled material S, the strain gauges 5.6 detect the respective loads and input the values to the adder 15. The adder 15 adds the two load values to obtain the total load and sends that value to the tension calculation device 16.
Output to.

The tension calculation device 16 calculates the tension of the rolled material S based on the total load value, and outputs the obtained tension value. The deviation between this tension value and the target tension is determined and input to the control compensation device 17. The control compensation device 1
In step 7, the speed correction value Δ is determined, and the obtained speed correction value Δ is output. Next, the sum with motor command replanting 0 is calculated.

The value obtained by the sum is the optimal speed command, which is input to the speed control device 18, and the speed control device 18 changes the speed of the mill motor 19 according to the input optimal speed command value to keep the tension constant. control to keep the threading level of the rolled material S constant.

(Effects of the Invention) As explained above in detail, the present invention includes two detecting loaves that can move up and down, a method of performing looperless control based on the measured tension value by the rollers, and a system that performs looperless control based on the tension value actually measured by the rollers, and a method that is synchronized with the detecting rollers. By means of an induction heating device that moves up and down at the same time, ■ the ability to pass the rolled material is ensured, and ■ the level of the rolled material passing is extremely stable (within ±1551m).
The gap between the induction heating inductor and the induction heating inductor can be minimized, resulting in extremely high heating efficiency.
, 7 kg/nun2), there is no effect on the dimensional accuracy of rolled materials, and there are industrially effective effects such as making it possible to produce high-quality hot coils. can get.

[Brief explanation of drawings]

Figures 1 to 3 are explanatory diagrams showing an embodiment of the present invention. Figure 1 is an explanatory diagram showing the arrangement of the tension detection roller and induction heating device and the vertical movement synchronization control system, and Figure 2 is an explanatory diagram showing the tension detection roller and the induction heating device. FIG. 3 is an explanatory diagram showing an example of a tension control system, and FIG. 4 is an explanatory diagram showing a conventional looper one-type tension control. 1...front stage stand, 1a...F, roll, 2...
・Rear stage stand, 2a...F20-ru, 3.4...
Tension detection loaf, 5.6...Strain gauge, 7.8...
Fluid pressure cylinder, 9.10... induction heating device, 11.
12... Fluid pressure cylinder, 13... Synchronous cylinder,
14... Lifting solenoid valve, 15... Adder, 16...
Tension calculation device, 17... Control compensation device, 18... Speed control device, 19... Mill motor, 20... Looper roll, S... Rolled material.

Claims (1)

[Claims] (1) Two tension detection rollers that can move up and down are installed between the rolling mill stands that perform looperless tension control, and
An induction heating device that can move up and down in synchronization with the up and down movement of the detection roller is arranged between the detection rollers, the rolled material is held horizontally between the detection rollers, and the gap between the induction heating device and the heating inductor is kept constant. A hot rolling method characterized by rolling while holding.