JPS5829514A - Automatic controlling method for reversible rolling mill - Google Patents

Abstract

PURPOSE:To minimize an idle time while protecting a rolling mill, by computing a minimum bite releasing speed from a rolling condition at the present pass and a bite releasing speed in neglecting a protection of journal bearings, and controlling the bite releasing speed basing on the larger value between both computed values. CONSTITUTION:When a controlling device 9 recognizes a biting of a material by a signal of a load cell 8 in an oil film bearing type reversible rolling mill, the device 9 estimates the sheet thickness, rolling speed, acceleration and deceleration ratio, and the time required for positioning between rolling passes. Further, a minimum bite releasing speed is computed from a rolling load and a lubricating oil temp. of the bearings, both measured at the present pass, and further, a bite releasing speed to make an idle time between the passes minimum in neglecting a protection of the bearing is also computed. A bite releasing speed, corrected by an estimated rolled sheet length after the starting of biting, an actual rolling speed, and a timing signal of run-out is computed basing on the larger value between both the computed values, by inputting a signal of a pulse generator 6 generated in accordance with the rotation of the work roll 1 to the device 9. An acceleration and deceleration rate of a table after the bite releasing is controlled by instructing a table motor 4 and a rolling motor so as to make the speed at the time of actual bite releasing coincident with this computed value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic control method for a 5T rolling mill. More specifically, the oil-impingement type reversible rolling mill has independently controllable tables for transferring the rolled material at the front and rear. At the same time, the idle time from the biting release to the next bus's biting trench is minimized with moe pressure +1441
This relates to the automatic control method No. 4.

In rolling with a reversible rolling mill, the material needs to be bitten into the rolling mill after downstream positioning and positioning of the front bag surface side guide are completed, and in some cases, the material must be rolled into the rolling mill.
It may be required to separate the material to a distance corresponding to the descaling nozzle position on the front surface of the machine. In either case, biting is required at a predetermined speed, but conventionally,
T5'I Efforts have been made to minimize the time from the time when the material is released until the next pass bite within the range that satisfies the above-mentioned limiting condition.

For example, in Gekibun i@46-27 [No. 343, after the material is released, the entire release speed is calculated so that it will be inserted into the next pass exactly after the gap time required for setting the reduction. In this issue, for example, we propose a method for calculating the release speed in which the material flows to the descaling nozzle position and is then transferred to the next pass in the minimum amount of time.

In general, the thickness of the plate becomes thinner as the path progresses, so if we assume that the material acceleration/deceleration rate by the table does not change much between the material and the slip, and if we ignore the flow distance limit, the material will bite at a predetermined speed in the minimum time. In this case, it is necessary to reduce the release speed. However, in recent years, due to the increase in speed due to the use of hydraulic pressure in the rolling positioning device, if the conventional method is fully applied, the expulsion speed will be extremely low, and the oil film bearing of the rolling mill will be completely damaged during milling. It's becoming more dangerous.

Here, the present invention takes into account the relationship between the load applied to the oil film +11] bearing and the safe rotation speed, and provides automatic control for a reversible rolling mill that can engage the oil film bearing in the minimum amount of time without rupturing the oil film bearing. It is intended to provide a method.

One feature of the present invention is that the release speed is calculated and controlled within a range that does not damage the oil film bearing. First, the method for calculating the release speed will be explained in detail.

According to the pass schedule meter by process calculation, the old speed (Vl) of the material on the inlet side at the time of biting that falls to j+1 pulse
, j+1 Bus pressure φ side guide positioning time (tg), descaling time! -41! (Specified flow c (L) of Nyoru material from the rolling mill, material limit deceleration 4 (α1) after releasing during j−j+1 pass, υ0 :il<rate(
α2) and rolling speed after acceleration during j-pass rolling (vMAX
), rolling load throat (P, i) k, respectively. However, if all actual product values are available at the time of performing these calculations, the net product value may be used. In addition, the flow length from the rolling mill is set to L = 0 if it does not have to be specified.

First, we find the total independent chewing and release speeds of each field subject to each limit. Regarding speed, the positive and negative values are ignored in calculations.

(a) When it depends only on the slippage between the material and the table.

(h), when it is rolled to a specified distance from the rolling mill (C), when the oil film thickness of the oil film bearing is guaranteed.

FIG. 1 is a diagram showing the relationship between the roll rotation speed M and the limit rolling load P) at each oil temperature (Toit), and these relationships are determined by the specifications of the rolling mill. The following values are determined by the graph search shown in FIG.

VC, 3= f (Pj, Toit) ・=
−= −(3)(d), when it depends on the time required for rolling down-side guide positioning.

FIG. 2 is a diagram showing the speed pattern after the material is blown out when the time required for positioning is long. In this figure, the area SA
= Area SB2 Area Sc - Area sD is required. Furthermore, due to the geometrical relationship, the process is divided into the following 211I□I processes according to the required time tgK for pass reduction and side guide positioning from load-off to load-on.

This is the same as when you target only the material and the table.

By solving the simultaneous equations of equations (4) and +, 5) from the relationship Vδ4·=Vδ1 SC=so, equation (6) is obtained.

cD 411AIiiN: (Release rate V6t,
The maximum value of V5z, Vδ3, and V154 is determined as the optimum release speed Vo. In addition, vO>
This cannot be achieved with VMAX, so it can be achieved by modifying α1 to a smaller value.In fact, when applying )■, this case is rare, so it will not be discussed here.

Next, a device k for realizing the release speed V5 calculated as described above and the subsequent forceful acceleration will be explained.

FIG. 6 is a block diagram showing an example of an apparatus for implementing the method of the present invention. In the figure, 1 is a work roll, 2
3 is an output table for transferring the rolled material, 3 is an output table roll, 4 is a table motor that drives these table rolls, 5 is a rolling motor that moves the work roll 1 by IRK, and 6 is connected to the work roll 1. , a pulse generator that outputs pulses corresponding to the rotational speed of the work roll, and 7 a detection means (H
MD), 8 is a detection means that is connected to the work roll 1 and detects whether the material is bitten or released, and for example, a load cell is used. Reference numeral 9 is a control device including, for example, a computer, which outputs a signal corresponding to 10 revolutions of the work roll from the pulse generator 6, a signal from the MD 7 to the HM/RM signal of the material, and a signal from the load cell 8. Material bite IJj
Recognition of release and number 1 are performed by 112 people each, and a split signal is output to the table motor 4 and rolling motor 5. In other words, this system "Wholesale device F7.91 = J, 0 charge 11i ■ included, 1 pick-up 147 by the bond month from load cell 8
5℃. When material biting is performed, VMAX simultaneously.

vi5, advance rate and ll:, 4 stop motor 5's 1 role large deceleration rate to start full speed, J, 3, and press plate 1 from material biting allowance. IfA is determined by the pulse signal from the pulse generator 6 connected to the turf work roll 1, and the deceleration start timing button is pressed to issue an IN2 speed command number ftI to the rolling motor 5. The first is that the actual rolling speed is 1.+V is lower than the motor characteristics, so the full actual rolling speed is not applied at the above deceleration start timing. It is possible to measure the deceleration command by delaying the deceleration command for all timers in response to the error.Secondly, as the material erosion becomes longer, the HMD 7 questions the front and back of the material, and the material's HM l) Buttonuki detects the timing and leaves the remaining υ
The above-mentioned deceleration timing is corrected based on the unrolled condition, thereby absorbing errors in the scheduled exit plate speed and advance rate.

Next, after the material has been spattered, a deceleration αl is applied to the table motor 4 on the exit side, and after the table motor 4 has stopped, an acceleration α2'f! is applied to the table motor 4. : Giving material to the next pass.

Numerical examples when the automatic groaning control method according to the present invention is applied to a hydraulic reduction type four-layer rolling mill are shown below.
The backup roll oil film bearing rotation limit for ON rolling load 1 is 16r, p, m at an oil temperature of 46℃, and the material speed is approximately 1.7m/sec (V03 = 1
．． 7m/sec). In addition, the rolling down positioning time t
g is, for example, 30'' (tg = 2.5 s for K)
It is ec.

In addition, the material limit decrease rate α
l, acceleration rate α! If total αl = αm = 1m/sec, j path exit thickness is 120 mm, and j + 1 path exit thickness is fully predicted at 901 m, the advanced rate is 6, taking into account the oil film bearing rotation limit.
．． When it is assumed to be 25%, the material speed Vi on the low input side becomes as follows.

Here, if we assume that all passes that do not cause damage are fixed, then from the method we used in the previous game, is it v? )1 = Vσ4 = 1.35m/5eeVD2
−υm/sec, V? )3 = 1.7 m/
sec is obtained, and the maximum value among them is 1.7
m/sec gold, determined as the optimum release speed Vcit. That is, in this case, Aburakan II! As far as i'll1l is concerned to protect the III Uke, it will be released.

In this example, the biting speed is set as low as possible because the rolling positioning time is short and the acceleration/deceleration rate of the rolling mill during rolling is lower than the acceleration/deceleration rate due to the friction between the material and the table during unbiting. This is the result of aiming for maximum rolling capacity based on the fact that it is usually large.

As explained above, the present invention calculates the degree of small eruption bed from the rolling load and l1IlIl receiving oil temperature of the current pass, and minimizes the idle time between passes ignoring the oil film bearing maintenanceffflk. The total speed is calculated, and the Q release speed of the rolling mill is controlled based on the larger value of the calculated values, and the information that determines the rolling interval after biting, the rolling speed, and the HMD bottom removal is also used. This information is used to issue all commands for sterilization timing, and it is possible to reduce the idle time while protecting the rolling mill.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between roll rotation speed and critical rolling load at each oil temperature, Figure 2 is a diagram showing the speed pattern after material 1 is released when the positioning time is long; 3
The figure is a block diagram showing an example of a system f+Tt that implements the entire method of the present invention. 1... Work roll, 2... Output table, 3...
・Output 1 table roll, 4... table motor,
5... Rolling motor, 6... Pulse generator, 7...
HMD, 8...load cell, 9...control device. Agent Patent Attorney Tadashi Sato Year 0υ Figure 1 Figure 2 Exit C ↑ 9

Claims (1)

[Claims] (1) In an oil slide type reversible rolling mill that has independently controllable tables for transferring rolled material at the front and rear, the current pass and next pass of the rolling mill are controlled by the plate thickness, rolling speed change, and on the table. Estimate the force 0 speed rate, the time required for positioning between buses,
From the rolling load of the current pass and the receiving oil temperature, a minimum of 4 release speed changes are calculated, and the total amount of release speed is calculated to minimize the idle time between passes, ignoring the oil and the receiving section j. The larger value of both ears is adopted, and the information on estimating the rolling extension after biting, the actual rolling speed, and the information on the HMD tail are corrected, and the speed at the time of biting and release is the obtained rolling speed. An automatic control method for a reversible rolling mill, characterized in that the deceleration of the rolling mill is commanded so that the acceleration and deceleration rate of the table after rolling is fully controlled.