JPS6268620A - Rolling control method for cold rolling mill - Google Patents

Abstract

PURPOSE:To prevent meandering of a strip and to improve the plate passing ability by adjusting at least one of leveling, bender, roll shift, and draft distribution of a rolling mill based on a plate thickness distribution measured at the inlet side of a cold rolling mill. CONSTITUTION:A 5-stand-cold rolling mill detects a plate thickness distribution in the lateral direction of a steel plate 10 by using a plate thickness profile meter 21 set at the inlet side of the 1st stand 1 and predicts the sectional profile of the plate 10 in the outlet side of the 5th stand 5 based on the above detected result. Then, one of leveling, bender, roll shift amount, and draft balance of the rolling mill is set at an optimum value based on the predicted sectional profile and cold rolling of the plate 10 is performed. This method prevents meandering of strips and improves plate passing ability remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rolling control method for a cold rolling mill that improves the rootability of a strip.

[Prior Art] In a conventional cold rolling mill, thickness gauges are installed on the entrance and exit sides of the cold rolling mill and between the stands to detect the thickness at the center in the width direction of the strip being passed. By adjusting the amount of reduction by the rolling rolls based on the thickness detection results, rolling is controlled to obtain a strip with a predetermined thickness. On the other hand, the thickness profile of the strip in the plate width direction is measured on the exit side of the rolling mill, and the cross-sectional shape of the strip exiting the rolling mill is inspected.

[Problems to be Solved by the Invention] However, if the hot-rolled sheet supplied to the cold-rolling machine, that is, the hot-rolled original sheet to be cold-rolled, has an abnormality in cross-sectional shape such as uneven thickness, When such strips are supplied to a cold rolling mill, the load and tension balance on each rolling stand will be disrupted, causing defects in the shape of the strips.
The strip's permeability and drawability may deteriorate, and the strip may become meandering.

Conventionally, when strip threading abnormalities or meandering occur, the operator who monitors the running of the strip performs measures such as distribution of rolling reduction, adjustment of roll bender amount and roll shift amount, and leveling adjustment for each coil. Correct. However, due to the slippage of the sheet at high speed (about the lip),
If the pelleter judges the runnability of the strip and adjusts leveling, etc., corrections will be delayed and operational problems will likely occur. When such operational troubles occur, there are problems such as breakage of the strip, damage to equipment, deterioration of roll consumption rate, and reduction in operating rate.

[Means for solving the problem] This invention has been made in view of the above circumstances, and necessarily includes the following:
To provide a rolling control method for a cold rolling mill, which can prevent meandering of the strip, improve the permeability of the slips in the rolling mill and the center property of the rear part of the strip, and avoid operational troubles. The purpose is to

The rolling control method for a cold rolling mill according to the present invention includes a plate thickness profile meter that measures the thickness distribution in the width direction of a material to be rolled before rolling on the entry side of the cold rolling mill. Predict the cross-sectional shape of the material to be rolled at the exit side of the cold rolling mill based on the detection results, and adjust at least one of leveling, bender, roll shift, and reduction distribution of the cold rolling mill based on this cross-sectional shape. It is characterized by

"Example" Hereinafter, an example of the present invention will be described with reference to the attached drawings. FIG. The hot-rolled original sheet is unrolled from the uncoiler 6, passes through the first to fifth rolling stands], 2°3.4.5, and is wound into a coil rough.

Each rolling stand 1 to 5 has a pair of work rolls 8 and a
While the steel plate 10 passes through the rolling stands 1 to 5, the steel plate is rolled to a predetermined thickness, and a cold rolled coil 11 of a predetermined thickness is manufactured.

A plate thickness profile meter 21 that measures the distribution of plate thickness in the width direction of the steel plate 10 is installed on the entry side of such a rolling mill. Moreover, thickness gages 22 and 23 for measuring the thickness of the steel plate 10 at the center in the width direction are installed on the entry and exit sides of the rolling mill. The measured values of these thickness gauges 22 and 23 are used in the cold rolling mill to control the plate thickness to a predetermined value, as in the past. The feature of the rolling control method according to the present invention is that a thickness profile meter 21 is installed on the entrance side of the cold rolling mill to measure the cross-sectional shape of the steel sheet O entering the cold rolling mill, that is, the thickness distribution in the width direction. Based on this measurement result, the leveling, bender, roll shift, or reduction distribution of each rolling stand is controlled by four feeder words.

FIG. 2 is a flowchart showing this rolling control method. The plate thickness numerator fi31 in the width direction of the steel plate 10 is determined by the plate thickness profile meter 21. This plate thickness valve I531
, hF and hD are the differences between the maximum thickness of the steel plate and the thickness at the ends in the width direction of the steel plate, and indicate the degree of decrease in the thickness at the ends in the width direction of the steel plate. The detection signal of the plate thickness profile meter 21 is subjected to digital conversion, etc., and then inputted to an arithmetic circuit constituted by a microcomputer or the like.

First, the plate thickness force measured by the plate thickness profile meter 21
31 is a difference calculation step 32 and an average value calculation step 3
3 is input. In this difference calculation step 32-, hF
and hD (of the wedge) hwa=hF−h,) is calculated. On the other hand, in the average value calculation step 33, the average value (profile amount) of hp and hD hpo =
(hF+ho)/2 is calculated.

The calculation result of the difference calculation step 32 is input to a prediction step 34 that predicts the wedge amount on the exit side of each stand. On the other hand, in the prediction step 35 for predicting the profile amount and shape on the exit side of each stand, the wedge fa h 1.1/D of the steel plate before entering the cold rolling mill is calculated from the difference calculation step 32 and the average value calculation step 33. and profile 5A h po are input. Further, the predicted value of the wedge 5 is input from the wedge prediction step 34 to the profile and shape prediction step 35. In the wedge mother-child side step 34, the wedge amount hv(1) on the exit side of the first stand 1 to the fifth stand 5.

hw <2>, hw (3), hw (4), hw (
5) is predictively calculated according to the following functional formula (1).

hw (i>=f (P(ri, h(ri・, hw (
! -1), 5(i), B(i>) ...(1
) iBL, i=1, 2. 3. 4.
5P(i); load h(i); plate thickness hv (ri: leek edge (difference in thickness at the edge of the steel plate in the width direction) S(i); shift amount (when the work roll shifts in the width direction of the steel plate) B (il bender pressure (bender force applied to work roll)
, hp (3), hp (4), hp (5) and shape factors hE (1), hE (2), hE (3).

hE(4) and hg(5) are the following functional formula (2).

Prediction calculation is performed according to (3).

hp (i>=Q (P (i>, h (i>, B
(i).

S(ri, hp (i-1>, hw (!-1))...
・(2) hr: (i>=k(P(i), h(i>, B(i>.

3(i), 11E(i-1>, hp (i-1))・
...(3) The calculation result of the calculation step 34 is input to the leveling amount calculation step 36, and in this calculation step 36, the required leveling amount ΔQ(i) to be provided in each stand is tightened according to the following function formula (4). Served.

80(i>=l(hw), h(i).

P(i)) ... (4) The calculation result of this calculation step 36 is input to the control circuit 40 that controls the leveling of each rolling stand, and the control circuit 40 calculates the leveling amount calculated in the calculation step 36. The leveling amount of each rolling stand 1 to 5 is changed so that

On the other hand, the shape factor calculated in calculation step 35 is input to determination step 37, and it is determined whether shape factor hE(i) is less than or equal to an allowable value.

Then, the shape factor t1E (if the ri is less than the allowable value, the profile suspension and shape factor are inputted to the determination step 38. In this determination step 38, the final plate crown is the eye) value or less? If it is below the target value, then the load P(i) and plate thickness h(
i), shift amount 5(i) and bender pressure B(i) are input from calculation step 35 to a control circuit 41 that controls the bender and rolling balance, and the control circuit 41 calculates the rolling amount of each rolling stand 1 to 5, The shift amount and bender pressure are set to those input from calculation step 35. Shape factor hE(i
) is not below the allowable value or the final plate crown is not below the target value, in step 39 the bender pressure B(i)
, the plate thickness h(i) or shift @S(i) is changed,
Again, the profile amount hp(i) and the shape factor hE (i>
is required.

These operations are repeated to determine the bender pressure, shift amount, and reduction amount.

In such a cold rolling number, the hot rolled coil is unwound by the uncoiler 6, and the hot rolled original sheet is supplied to the first to fifth rolling stands 1 to 5.

While being passed through each stand, the hot-rolled original sheet is rolled by rolling rolls to produce a cold-rolled steel sheet with a predetermined thickness. Before the hot-rolled original sheet enters the first rolling stand 1, the sheet thickness distribution 31 in the sheet width direction is measured by the sheet thickness profile meter 21, and the detection result of this sheet thickness profile meter is used in the difference calculation step 32 and the average value. It is input to calculation step 33. In a difference calculation step 32, a thickness difference hWo between both widthwise ends of the hot-rolled original sheet is calculated, and in an average value calculation step 33, an average value hPo is calculated.

In the profile (to) and shape factor prediction step 35, the load, plate thickness, bender pressure, roll shift amount,
Relationship between profile Φ and shape factor ((2>, (3)
(shown in the formula) is calculated and input in advance, and based on this relationship, each rolling stand (the first rolling stand)
rolling load P(i), plate thickness h(i), bender pressure B(i>
, shift as (i), profile information hp(i-1> and shape factor hE(i-
1), the profile ωhp(i) after rolling and the shape factor hE(ri) are determined.

Next, in step 37 and step 3B, it is determined whether the shape factor hE is below the allowable value and whether the final plate crown is below the target value, and if it is not below the allowable value or the target value. , the bender pressure s(*>, shift f
f1s(i) and plate thickness h(i> are changed, and hp(
ri and tlg(ri) are calculated, and step 38 is determined. This process is repeated until steps 37 and 38 are obtained.
The bender pressure B(i), shift is(i), and plate thickness h(i) that satisfy is input to the control circuit 41. Note that the corrected bender pressure B(i), shift 1ts(i), and plate thickness h(i) are also used in the calculation performed in step 34.

On the other hand, the wedge amount prediction step 34 includes load, plate thickness,
The relationship between the shift amount, bender pressure, and wedging amount (shown in equation (1)) is determined in advance and entered manually, and based on this relationship, each rolling stand (first rolling stand) From the rolling load P(i), plate thickness h(i), shift amount S(i>, and bender pressure B<i), and the wedge ffihw(i-1> before entering this rolling stand, the Find the wedge amount hw(i>).

Next, in step 36, the leveling amount ΔQ(i) is calculated. Usually, the gap amount of the rolling stand is set to be the same on the free side and the drive side, and the leveling matrix ΔQ(i) is O. However, if a hot-rolled original sheet has uneven thickness, if it is cold rolled as it is, the steel sheet will elongate unevenly, resulting in a meandering phenomenon. Therefore, in the cold rolling mill, it is necessary to set the gap amount in accordance with the hot-rolled original sheet, and the wedge amount hw (
When i> is not O, the gap amount in the rolling stand is set separately for the free side and the drive side, that is, the gap amount is set to be larger for h where the thickness of the hot rolled original sheet is thicker, The leveling amount ΔQ(i) is set so that the steel plate moves straight. This leveling amount △Q
(i) is input to the control circuit 40, i! lII control circuit 4
0 sets the leveling of each rolling stand 1 to 5 to ΔQ(i>).

If the pickling-cold pressure continuous mill is used, the Mugangi technique can also be applied to a fully continuous mill with a connection in front of the cold pressure. It goes without saying that in this case, the position of the incoming plate raw material can be any position as long as it is in front of the rolling process (for example, for washing).

According to this invention, the thickness distribution in the width direction of the hot-rolled original sheet entering the cold rolling mill is detected, and at least one of the leveling, bending, roll shift, and reduction balance of the cold rolling mill is detected. Since one is set to the optimal one based on the plate thickness distribution,
Meandering of the rolled material is reliably prevented, and mailability and handling of the temporary rear end are significantly improved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an implementation state of the present invention, and FIG. 2 is a flowchart showing a control mode thereof.

Claims (1)

[Claims] A plate thickness profile meter is installed at the entrance side of the cold rolling mill to measure the thickness distribution in the width direction of the rolled material before rolling, and based on the detection results of the plate thickness profile meter, A rolling control method for a cold rolling mill, comprising predicting the cross-sectional shape of a material to be rolled, and adjusting at least one of leveling, bender, roll shift, and reduction distribution of the cold rolling mill based on the cross-sectional shape. .