JP3143542B2 - Meandering control method for rolled material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling meandering of a rolled material for controlling meandering of a tail end portion of a rolled material in hot rolling.

[0002]

2. Description of the Related Art Generally, when the meandering movement of a rolled material from a roll center to a working side or a drive side during a rolling operation increases, the side surface of the rolled material comes into strong contact with a side guide, and the rolled material breaks, buckles, etc. May cause. Especially when the tail end of the rolled material comes off from the rolling mill and the tension is lost, it tends to meander greatly, and the large meandering at the tail end of the rolled material causes tail drawing, so the difference between the left and right rolling loads is A meandering control based on a differential load method, which detects meandering and performs leveling control so as to narrow the roll gap on the side where the rolling load has increased, is performed. However, the meandering control of the differential load method is intended to suppress meandering by tightening the roll gap on the side where the tail end of the rolled material meanders. There was a problem of attaching. Therefore, a method of detecting the trailing edge of the rolled material by a rolled material detector provided in the preceding rolling mill and opening the roll gap of the rolling mill to be controlled (Japanese Patent Laid-Open No. 551-161505).
However, since the thickness of the rolled material tail that does not cause shape defects due to the opening of the roll gap increases, the product does not become a product, the yield decreases, and the roll load is detected by opening the roll gap. Since the output of the vessel fluctuates abruptly, this fluctuation becomes disturbance noise, causing a malfunction of the meandering control of the differential load method, thereby causing a problem that the meandering control effect is reduced.

[0003]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to solve the above-mentioned problems and improve the product yield of rolled materials. In addition, disturbance noise caused by opening the roll gap causes malfunction in meandering control. Is to prevent it from occurring.

[0004]

According to the present invention, tracking of a rolled material is started from a point in time when a rolling load P _2t of a former rolling mill is reduced by a predetermined amount from a reference rolling load P _2t0 stored at the time of stable _threading. A meandering control of the rolling mill to be controlled, and predicting immediately before the tracked rolled material position passes through the rolling mill to open the roll gap of the rolling mill to be controlled. And, from the time when the rolling load P _2t of the former rolling mill is reduced by a predetermined amount from the reference rolling load P _2t0 stored at the time of stable passing, tracking of the rolled material is started and meandering control of the rolling mill to be controlled is performed. The roll gap of the controlled rolling mill is opened by predicting immediately before the tracked rolled material position passes through the controlled rolling mill, and the roll load of the controlled rolling mill is opened by opening the roll gap. When P _1t is reduced a predetermined amount than the reference rolling load P _1T0 stored at stable through plate is made more as the second invention, wherein the aborting control operation of the meander control of the control target rolling mill.

Next, an embodiment of the present invention will be described in detail with reference to the drawings. Reference numeral 1 denotes the work side and drive side rolling loads P _1W , P by the working side and drive side rolling load detectors 2a and 2b.
_The rolling mill 3 to be controlled in which _1D is detected has a rolling load difference ratio ΔP ₁ / P _1t = (P _1W −P) based on the rolling loads P _1W and P _1D.
1D ) / (P _1W + P _1D ), a rolling load calculator 4 for setting a predetermined control gain, and a meandering controller 4 based on the rolling load difference ratio ΔP ₁ / P _1t . To calculate the control output amount. Reference numeral 5 denotes a roll gap opening amount calculator which calculates the opening amount of the roll gap from a difference between a predetermined thickness of the inlet side plate and a thickness of the outlet side, and a control output amount of the roll gap opening amount calculator 5 and the meandering controller 4. Based on the sum, a reduction command is sent to the left and right reduction cylinders 6a and 6b, and the gap between the work rolls of the rolling mill 1 to be controlled is controlled to perform meandering control of the differential load method.

Reference numeral 7 denotes a work-side and drive-side rolling load detector 7.
According to a and 7b, the rolling loads P _2W and P _2D on the working side and the driving side.
Is a pre-rolling mill in which the rolling loads P _2W and P _2D are detected.
The rolling load calculator 9 calculates the rolling load P _2t = P _2W + P _2D from the reference rolling load P _2t0 stored at the time of stable _threading at the start of control and the rolling load reduction amount (P _2t0) from the current rolling load P _2t. -P _2t ) ≧ set value, and when the logic judgment circuit 9 judges that the rolling load has decreased by a predetermined amount, the speed detector 10 of the rolling motor of the rolling mill 1 to be controlled and The tracking calculator 11 starts the tracking for calculating the amount of movement of the defective shape portion of the rolled material or the movement of the tail end of the rolled material based on the rolled material retreat rate given in advance.

Reference numeral 12 denotes a change-over switch operated by a tracking calculator 11 which calculates and predicts immediately before the shape defect portion of the rolled material to be tracked or the tail end of the rolled material reaches the rolling mill 1 to be controlled. The switch 12 instructs the cylinders 6a and 6b of the controlled rolling mill 1 to open the roll gap and instructs the tracking completion. 13 is a rolling load detector 2a, 2 of the rolling mill 1 to be controlled.
b, the rolling load P _1W on the working side and the driving side detected by b.
A rolling load P _1t = P _1W + P _1D computed by the rolling load arithmetic unit 3 from P _1D, the rolling load reduction from the reference rolling load P _1T0 which were stored in the time control at the start of the stable communication board _(P 1t0
−P _1t ) ≧ the set value. The logic judgment circuit 13 switches the changeover switch 14 when the rolling load of the rolling mill 1 to be controlled is reduced by a predetermined amount due to the opening of the roll gap. Then, the control calculation of the meandering control is discontinued until the rolled material passes through the rolling mill 1 to be controlled by the changeover switch 14 being switched, and the leveling control output is held at the control amount at the time of termination of the control computation,
After the tail end of the rolled material passes through the rolling mill 1 to be controlled, all control outputs are cleared to eliminate disturbance noise.

In the following, the present invention will be described with reference to an apparatus for implementing the present invention. , The rolling load detectors 7a and 7b of the pre-mill 7
Thus, the rolling loads P _2W and P _2D on the working side and the driving side are reduced. The rolling loads P _2W and P _2D are calculated by the rolling load calculator 8 to calculate the rolling load P _t2 , and the logic judgment circuit 9 calculates the difference between the reference rolling load P _2t0 and the rolling load P _t2 and the reduction amount of the rolling load (P _2t0 − It is determined that _Pt2 ) ≧ set value has decreased by a predetermined amount. With this determination, the defective shape of the rolled material and the tail end of the rolled material are tracked based on the speed detector 10 of the rolling motor of the rolling mill (1) to be controlled and the reverse speed.

At this time, the rolling load calculator 3 calculates the rolling load difference ratio ΔP ₁ / from the working side and driving side rolling loads P _1W and P _1D detected by the rolling load detectors 2a and 2b of the rolling mill 1 to be controlled. _{P 1t = (P 1W -P 1D} ) / (P 1W + P 1D)
Is calculated, and a control output amount is calculated by the meandering regulator 4 set to a predetermined gain based on the rolling load difference ratio ΔP ₁ / P _1t , and the control output amount, the input-side plate thickness given in advance, and A reduction command is sent to the left and right reduction cylinders 6a and 6b based on the sum of the control output amounts of the roll gap opening amount calculator 5 that calculates the roll gap opening amount from the difference in the outlet side plate thickness, and the work of the rolling mill 1 to be controlled is sent. The meandering is suppressed by controlling the gap between the rolls.

[0010] Then, the shape defect portion of the rolled material or the tail end of the rolled material.
Is calculated and predicted just before passing through the rolling mill (1) to be controlled.
The changeover switch 12 is turned off by the tracking arithmetic unit 11
Command to complete tracking, and
The roll gap of the target rolling mill 1 is opened. This row
The rolling load P of the rolling mill 1 to be controlled by opening the gap _1t
And reference rolling load P_1t0And the reduction in rolling load (P_1t0
−P_1t) ≧ Set value has decreased by a predetermined amount.
Path 13 and the changeover switch 14
Is switched by the circuit 13 to roll the rolling mill 1 to be controlled.
Meandering until the defective shape of the material or the tail end of the rolled material comes off
Terminates control calculations and controls leveling control output.
It is held at the control amount at the time of the termination. And rolled material tail end
After the section has passed through the rolling mill 1 to be controlled,
Clear the output to eliminate disturbance noise
You. In addition, the rolling load of the former rolling mill 7 and the rolling mill 1 to be controlled.
By adjusting the set value of the weight reduction, the roll gap
Release timing and meandering control termination timing
It can be set optimally.

[0011]

As is apparent from the above description, the present invention is characterized in that the reference rolling load storing the rolling load at the time of stable threading of the pre-rolling mill, the defective shape of the rolled material and the tail end of the rolled material are reduced. Based on the difference in the rolling load when passing through the preceding rolling mill, the defective shape of the rolled material and the tail end of the rolled material are tracked, and the meandering control of the rolling mill to be controlled is performed. The roll gap of the rolling mill to be controlled is opened by predicting immediately before the end of the rolled material and the tail end of the rolling material pass through the rolling mill to be controlled. So you can
The tail of the rolled material, which was conventionally discarded, can be made into a product, and the product yield is improved. In addition, since the roll gap of the rolling mill to be controlled is opened by predicting the shape defect portion or just before the tail end of the rolled material passes, as in the case of the meandering control of the differential load method, the roll roll flaw caused by the trailing end reduction is used. Accumulation can be accurately prevented. In addition, the control calculation is terminated when the roll gap is opened based on the difference between the reference rolling load that stores the rolling load during stable threading of the controlled rolling mill and the current rolling load. A sudden change in the output of the rolling load detector does not become disturbance noise, and the meandering control effect is not lost. Moreover, the system is simple and can be provided at low cost. Therefore, the present invention is of great benefit to the industry as a meandering control method for a rolled material that solves the conventional problems.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the operation timing of the present invention.

[Explanation of symbols]

 1 rolling mill to be controlled 2 pre-mill

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-266414 (JP, A) JP-B-7-96124 (JP, B2) Patent 2565600 (JP, B2) Patent 2706342 (JP, B2) Patent 2539877 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) B21B 37/68

Claims (2)

(57) [Claims] When the rolling load P _{2t of the} preceding rolling mill (7) is reduced by a predetermined amount from a reference rolling load P _2t0 stored during stable _threading , tracking of a rolled material is started and a rolling mill to be controlled is started. The meandering control of (1) is performed, and the roll gap of the controlled rolling mill (1) is opened by predicting immediately before the tracked rolled material position passes through the controlled rolling mill (1). Meandering control method for rolled material. 2. When the rolling load P _{2t of the} former rolling mill (7) is reduced by a predetermined amount from the reference rolling load P _2t0 stored during stable _threading , tracking of the rolled material is started and the rolling mill to be controlled is started. The meandering control of (1) is performed, and the roll gap of the controlled rolling mill (1) is opened by predicting immediately before the tracked rolled material position passes through the controlled rolling mill (1), and the roll gap is opened. Rolling mill controlled by (1)
When the rolling load P _1t of the rolling mill is reduced by a predetermined amount from the reference rolling load P _1t0 stored during stable passing, the control calculation of the meandering control of the rolling mill (1) to be controlled is terminated. Method.