JPS5976610A - Hot rolling method of steel plate - Google Patents

Abstract

PURPOSE:To make the temperature distribution of a steel plate uniform, by adjusting a gap between a work roll and a draining board in accordance with the rolling conditions such as the king of steel, rolling size, and rolling temperature of a material to be rolled, and regulating the flow rate of cooling water to be supplied to the peripheral surface of the roll. CONSTITUTION:In a hot rolling mill where a steel plate 20 is hot-rolled by a work roll 2n, a gap between a draining board 8n and the roll 2n is made freely adjustable by a rod 9a of an air cylinder 9. Rolling conditions (l) such as the kind of steel, use, rolling size such as the thickness and width of a slab, unit weight, temperature at the inlet side of a stand, and target temperature of rolling, are previously inputted to a calculator 14. Then, a sequence controller 13 controls a pressure regulating valve 12a through a pressure regulating gauge 15 and a 1/P converter 16a, basing on a cooling pattern commanding signal (h) outputted from the calculator 14, to control the gap between the board 8 and the roll 2n by the cylinder 9. Accordingly, the flow rate of cooling water to be supplied to the peripheral surface of the roll 2n is regulated to make the temperature distribution of the plate 20 uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rolling method for uniformizing the temperature distribution in the longitudinal direction of a rolled material in hot rolling of a steel plate.

As is well known, for example, hot finishing rolling of steel plates involves tandem hot rolling in which a plurality of rolling stands are arranged so that rolling can be carried out.
Is the arrangement of the well-known hot finishing rolling mill shown in Figure 1, which was probably carried out by Yu? In the schematic diagram shown, sila, lb...1n is n
1 shows a hot rolling mill consisting of base rolling stands, each stand being rolled from work rolls 2a, 2b, 2n and knock-up rolls 3a, 3b, 3n. Stretches 20 of the material to be rolled are continuously rolled on these stands.
It is cooled and wound into a coil by a winding machine 6.

7a, 7b, and 7n are cooling water nozzles for cooling the valley work rolls, and 8a, 8b, and 8n are drain plates.

Now, as is well known, this drain plate is provided to prevent the roll cooling water from falling on the surface of the rolled material and reducing the temperature of the rolled material to an excessive degree. The pressing force was applied to the extent that a slight water film was formed around the work roll rtu. In other words, if all water cutting is performed at the water cutting/saka stage, it is possible to prevent the temperature of the rolled material from decreasing due to the roll cooling water, but the surface of the roll may become rough due to the water being exposed to four temperatures during the water cutting. This is because there was a problem that it was easy for this to occur. Therefore, conventionally 1
10-rutience IMJ rolling with a set of work rolls
As mentioned above, it is common sense to press the draining plate with a constant pressing force throughout the summer. In the case of copper and &, the effect of the temperature drop due to the roll cooling water mentioned above is large, so
In order to maintain the desired finishing rolling temperature on all sides, it is necessary to make the extraction temperature of the slab from the heating furnace the same throughout the city, or to install a heating device between the rough rolling mill and the finish rolling mill. All the heating energy was needed.

On the other hand, in Fig. 1, the finish rolling speed until the top (the leading edge in the length direction) of the rolled material 20 is wound around the mandrel of the winding machine 6 is such that the running performance on the runout table 4 is stabilized and The conventional method is to use a low speed to perform smooth rolling, and to carry out rolling at a still high speed by zooming after winding on a mandrel.

As a result, the temperature at the exit side of the finishing mill inevitably differs between the top of the material to be rolled and the start of high-speed rolling, and the subsequent temperature on the exit side of the finishing mill, posing a quality problem.

The present invention is a disciplined rolling method devised to solve the conventional problems as described above, and its purpose is to adjust the rolling conditions such as the steel type of the material to be rolled, the rolling size, and the rolling temperature. By adjusting the gap t between the work roll and the draining plate and adjusting the amount of cooling water on the roll circumferential surface, it is possible to solve local problems in the longitudinal direction of the rolled material (excessive or insufficient cooling) and improve the roll surface curvature. The objective is to make the temperature distribution of the steel plate uniform while maintaining the temperature distribution.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be explained based on drawings.

FIG. 2 obviously shows an example of the structure of an arbitrary rolling stand 1n that implements the present invention, and to simplify the explanation, this figure only shows the control of the drain plate 8n provided at the rear of the upper work roll 2n. . Actually, all the draining plates for the upper and lower work rolls of a hot finishing rolling mill that consists of multiple stands? It may be determined as necessary whether to use a similar control configuration or to select an arbitrary number of stands.

The rod 9a of the air cylinder 9 is connected to the drain plate 8n, and a gap of 114 nodes is freely provided between the outer peripheral surface of the work roll 2n and the drain plate (In).

10 is an air source that supplies a constant atmospheric pressure, and a magnetic switching valve 1
Reference numeral 1 is provided to switch between the operation of the air cylinder 9 and the release when the draining plate 8n is withdrawn due to roll change or the like. The pressure regulating valve 12a is a valve that regulates the pressurization -Ak to the air cylinder 9, and the pressure regulating valve 12b is a valve that regulates the amount of pressure released to the atmosphere.

The sequence controller 13 inputs the turn command signal from the computer 14 to the cooling engine and the tracking signal I, and sends the pressure setting signal j to the pressure adjustment cap 15, and also sends the electromagnetic switching valve 11 to actuate and release the pressure of the air cylinder 9. A signal kt is output. 16a and 16b are the pressure regulating valves 12
These are I/P converters respectively provided between a and 12b and the pressure adjustment J115.

A pressure oscillator 17 detects the actual pressure f'L applied to the air cylinder 9 and inputs it to the pressure regulator 15 to perform feedback control of the system.

In addition, @1 ■ Calculation 14 can be calculated by using the existing AGO control meter, the steel type of the material to be rolled, its purpose, the rolling size of the slab thickness Φ width, the unit weight, the temperature at the entrance of the stand, and the target rolling temperature. Since rolling conditions (4) such as If it is not possible to adjust the spacing, it is of course not possible to use any means such as a hydraulic cylinder or a single-pressing screw.

Using the apparatus configured as described above, Honko Myouken performs Nige IL using the following procedure.

Said total>'4-(Medium V of 14th grade is the steel type of 4th grade to be rolled,
The turning angle is set in advance according to the plate thickness and temperature. This cooling pattern is based on the actual measurement value of the temperature distribution at n output p1 in the length direction of the pressurized residual material.As a reference, the gap between the draining plate 8n and the work roll 2n is adjusted, and the roll circumferential surface is Cooling wound for:
This refers to all the lengths of the installation foot that change within the length of the rolled material.

Misfire ψ] The Ministry and others tried the following experiments to set the ξ turn of the failure resistance.

Figure 3 (I L (Ron, No. 0 is the second stage rolling process (F2) of the finishing press consisting of 6 stands (F2) (? - The degree of water removal for the work rolls is set at the conventional level and the two with strong water removal. This is a comparison of the temperature of the valley part of the pressure-bearing material when divided into stages.The presence or absence of draining and the top, middle, and bottom parts in the figure are as shown in Table 1. Figure 3 (a) shows that the temperature on the 12LB side has improved by about 8°C at a part of the coil center compared to the temperature on the F2 person side, and Figure 3 (b) shows the temperature on the exit side of the final soil compaction machine (F6). A temperature increase of 5 to 6 degrees Celsius can be seen for the top, middle, and bottom.
(The third figure shows the temperature at the coil edge portion on the exit side of the final finishing rolling machine, and it is clear that the temperature rises by 3 to 5°C.

Based on the above experimental results on one stand, we confirmed that the temperature increase due to water draining was fully confirmed.1 Afterwards, we applied this to multiple rolling stands by adjusting the cooling temperature within the length of the rolled material or between the rolled materials. All findings indicate that a significant temperature increase can be obtained without causing any inconvenience such as roughening of the work roll surface. In addition, as mentioned above, in the conventional method, the temperature distribution in the longitudinal direction of the rolling process has a large temperature drop at the 1rfK top part and the bottom part where the residence time of the rolled material is long before rolling, as shown by the solid line in Figure 4. An attempt was made to equalize the temperature over the entire length by adjusting the cooling water in the length direction. The curve shown by the broken line in the figure shows the water ψ [high, medium,
This is the result of setting the ξ turn (controlled in 3 stages of weak). 4-1 at the top and bottom: Compared to the conventional method, the temperature on the finishing exit side has increased by about 10℃, and in the middle section, the draining U[ By making the heating weak, the temperature decreases by 5 to 6°C, which is the most significant effect in equalizing the temperature of the entire length of the coil. Note that the degree of water drainage in this example was 10 as a pressing force against the work roll circumferential surface.
kglj (weak).

30kz nail (medium), 50kf sada (1 sebaceous membrane added).

The on/off of each cooling pattern is controlled by tracking information i, but in the old days, it was set according to the rolling speed starting from the point when the top of the material to be rolled was bit into the control stand, or it was set to the cutting wall. It is also possible to use other methods such as setting the top haiku signal via a timer.

FIG. 5 shows an example of mounting a draining plate 8n, and a support shaft 31 is attached to a fixed beam 30 fixed to the stand housing. It is supported on a mounting base 327 with a swinging mechanism via I. An aerosol ring 9 is provided on the mounting base 32 of the cylinder 9, and by the vertical movement of the air cylinder 9, the link mechanism 33 is operated so that the cutting plate 8n is fully pressed against the work roll 2n. ing. When changing the work roll 2n, one end of the work roll 2n is configured to be retracted by operating a changing air cylinder 34 which is swingably attached to the mounting base 32. 35 is a steel plate guide on the entry side.

The temperature control of the present invention is further improved.
In addition to the above-mentioned cooling pattern, it is also possible to measure the entire temperature at the entrance to the stand of the valley 1b1, and to record the degree of water draining continuously based on the temperature.

According to this research, the temperature distribution in the length direction of the rolled material is made uniform, which not only improves quality but also greatly reduces the heating energy of the slab.
For the S component, reducing the scale flaws can be expected by weakening the water drain and lowering the temperature compared to conventional methods.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the equipment series of a conventional hot finishing pressure 9L machine, Fig. 2 is a schematic diagram of an example of the equipment in which the present invention is implemented, and Fig. 3 (in, (b), ←→ is a cooling water drain system). FIG. 4 is a graph showing the effect of the implementation of the present invention, and FIG. 5 is a partial explanatory diagram showing an example of installing a draining plate. 1a, 1b, 1n...Rolling stand, 2a, 2b. 2n...Work roll, 20...Pressure material, 7a
, 7b. 7n...Cooling water nozzle, 8a, B)),
8 n... Draining board, 9... Air cylinder, 10
...Air source, 11...Solenoid switching valve, 12a, t2
b...Pressure adjustment valve, 13...Sequence controller, 14...=TSA, 15...Pressure regulator, 16
a, 16 b... I/P converter, 17... pressure oscillator. Agent: Patent attorney Masaaki Akizawa and 2 others? 3 ffi (A) F2 people 4FlIυshi11 Do I2"Mido7L-Sat-Top^ Pu・3Figure(B) To Noa Mi)"L 7+') to Neck 4
M 75 figure

Claims (1)

[Claims] In a hot rolling mill for steel plates, the gap between the drain plate and the work roll is freely adjustable, and the material to be rolled is adjusted according to the rolling conditions such as the rolling size, rolling temperature, etc. of the material to be rolled. To select an arbitrary period during the entire passage of the machine, completely adjust the gap, reduce the amount of cooling water on the circumferential surface of the roll by 1, and change the amount of swamp water attached to the rolled material to completely eliminate local excessive or insufficient cooling of the material to be rolled. A method for hot rolling a steel plate, characterized by: