JPH0659483B2 - Method for measuring rolling plate deformation resistance - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for online measurement of deformation resistance of a rolled plate in strip differential speed rolling.

[Prior Art] Even when a coil made of the same material is rolled, the hardness varies depending on the coil, so that the deformation resistance of the rolled plate also varies. Therefore, it is necessary to consider the deformation resistance of the rolling plate when setting the roll gap of the work roll of the rolling mill regardless of the constant speed rolling or the differential speed rolling. Thus, conventionally, there is no means for measuring the deformation resistance online, so the work roll gap is set based on the experience and intuition of the worker.

However, in operations that rely on the experience and intuition of workers, there are limits to the labor saving of the rolling line and the plate thickness accuracy of the obtained products. On the other hand, in the case of ordinary constant speed rolling, The relationship of Since the above relationship has been conventionally known, it has been considered that the deformation resistance K of the rolled plate may be obtained online from the equations (i), (ii), and (iii).

However, P; rolling load t _f; front tension t _b of the rolled sheet; rear tension Δh of rolled plate; the difference between the delivery thickness _{h 1} incoming and outgoing side thickness _{h 0 (h 0} -
h ₁ ) R ′; flat roll radius during rolling R; roll radius B; strip width f (μ); rolling force function considering friction coefficient μ C; variable E; Young's modulus ν; Poisson's ratio However, in the above formula (i), it is necessary to obtain the friction coefficient μ between the work roll and the rolling plate, but the friction coefficient μ
Is obtained empirically, and there are various formulas for obtaining the rolling force function f (μ), but the results vary depending on which formula is selected, and the friction coefficient μ is determined from the rolling torque. However, it is difficult to back-calculate the friction coefficient in ordinary constant velocity rolling, and even if the deformation resistance K of the rolled plate is obtained from the formula (i), an accurate value cannot be obtained and reliability may be lacked. is there.

The present invention has been made in view of the above circumstances, and an object of the present invention is to online measure the deformation resistance when a rolling plate is rolled at different speeds.

[Means for Solving the Problems] The present invention provides a rolling method, a rolling plate, and a rolling plate, in which rolling is performed at different speeds by passing the plate between the low speed side work roll and the high speed side work roll without winding the plate. In addition to detecting the front and rear tensions of the rolling plate, the inlet side plate thickness and the outlet side plate thickness of the rolled plate are detected, or the inlet side plate thickness of the rolled plate is set and the outlet side plate thickness is detected. To obtain the deformation resistance of the rolled sheet online.

[Operation] The rolled plate is passed between the low speed side work roll and the high speed side work roll without being wound, and the detected rolling load, front and rear tension of the rolled plate, detected input and output side plates. Based on the thickness or the set inboard thickness and the detected outboard thickness,
Without obtaining the friction coefficient between the rolling plate and the work roll,
Deformation resistance of the rolled plate is required online.

Embodiments Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the principle of the present invention will be described with reference to FIGS. 2 and 3. However, in FIGS. 2 and 3, 1 is the low speed side work roll, 2 is the high speed side work roll, N ₁ is the low speed side work roll neutral point, N ₂ is the high speed side work roll neutral point, and O ′ is the low speed side. It is the center of work roll 1.

Thus, the projected contact length l during rolling shown in FIG.
From the figure, l ² + (R′−Δh / 2) ² = R ′ ² is obtained. Next, since Delta] h ^2/4 is a small value negligible, Becomes

Further, in the case of different speed rolling, the rolling load does not have the friction hill which occurs in the case of constant speed rolling as shown by the chain double-dashed line a in FIG.

Therefore, even when the rolling plate S is passed through the work roll without being wound, and the different speed rolling is performed, the coefficient of friction μ between the low speed side work roll 1 and the rolling plate S and the high speed side work roll 2 and the rolling plate S The rolling load per unit length in the lateral direction of the roll is represented by the area of the slanted trapezoidal portion in FIG. 3, regardless of the friction coefficient μ with S. Multiplying the width B gives the total rolling load P.

Further, in rolling, when the stress state in the rolled plate S between the rolls 1 and 2 becomes large so as to satisfy the yielding condition, it is deformed, and the plate thickness can be made thin. Is a plane strain state, and the expression of this yield condition is represented by σ ₁ −σ ₂ = K. Where σ ₁ is the maximum principal stress, σ ₂ is the minimum principal stress acting in a direction orthogonal to the maximum principal stress σ ₁ , K is the deformation resistance, and σ ₁ and σ ₂ are the compressive forces. It is expressed as a plus, and when a tensile force acts, it is expressed as a minus.

On the rolling mill entry side, σ ₁ = p ₁ (p ₁ is the rolling load on the rolling mill entry side), σ ₂ = −t _b (t _b is the backward tension of the rolling plate), and On the delivery side, σ ₁ = p ₂ (p ₂ is the rolling load on the delivery side of the rolling mill) and σ ₂ = −t _f (t _f is the forward tension of the rolled plate) are entered into the above-mentioned yield condition equations. , P ₁ + t _b = K, p ₂ + t _f = K, which can be summarized as shown in FIG. 3, p ₁ = K−t _b on the rolling mill entrance side and p ₂ = K on the rolling mill exit side.
-T _f .

Therefore, the area of the slanted trapezoidal portion in FIG. Therefore, by multiplying this by the plate width B of the rolled plate S, the total rolling load P is Holds, and from equation (iv) Is required. Therefore, the deformation resistance K of the rolled plate s can be measured online without obtaining the friction coefficient μ from the equations (v) and (ii) and (iii).

Further, the front tension t _f shown in FIG. 3 is the tension value t _{f1 under the} PV condition.
If it deviates from it, as shown in Fig. 4, the high-speed side advanced rate That is, v ₁ ≠ V ₁ (where v ₁ is the exit plate speed, V 1
₁ is the work roll peripheral speed on the high speed side, but the rolling load P hardly changes even when the front tension t _f changes as shown in FIG. 5, so equation (v) is used when the advance ratio f ≠ 0, that is, It can also be applied when the neutral points N ₁ and N ₂ deviate from the inlet and outlet of the rolling section. Here, the PV condition means a state in which the low speed side neutral point coincides with the rolling section inlet and the high speed side neutral point coincides with the rolling section outlet.

Next, a specific example of the present invention will be described with reference to FIG.
3 is a load detector such as a load cell, 4 is a tension detector for the front tension t _f of the rolled plate s, 5 is a tension detector for the rear tension t _b , 6 is an inlet side thickness detector, and 7 is an outlet side. The signal detected by the load detector 3, the tension detectors 4, 5 and the plate thickness detectors 6, 7 can be sent to the calculator 8.
Further, to the calculator 8, the strip width B of the strip s, the work rolls 1,
The radius of 2 and equations (ii) (iii) (v) can be set. When the entrance side plate thickness h ₀ is set, the entrance side plate thickness detector is unnecessary. The entrance side plate thickness h ₀ is set in the case of a rolled plate in which there is little variation in the size of the entrance side plate thickness h _{0 in} the longitudinal direction.

As shown in FIG. 1, at the time of different speed rolling by passing a strip, the strip thickness detector 6 determines the entrance strip thickness h ₀ , the strip thickness detector 7 determines the exit strip thickness h ₁ , and the tension detector 4 determines the forward tension t. _f
However, the rear tension t _b is
The rolling loads P are detected by 3 respectively, and the signals thereof are sent to the calculator 8, and the deformation resistance K of the rolling plate s is obtained by the equations (ii) (iii) (v) regardless of the friction coefficient. The deformation resistance K thus obtained is sent to the arithmetic and control unit, the roll gap correction amount due to the change of the deformation resistance K in the downstream rolling mill is calculated, and the roll gap is adjusted based on the calculation result.

Note that the present invention is not limited to the above-mentioned embodiment, the entrance side plate thickness may be set without detecting, and other various changes are made without departing from the gist of the present invention. Of course you can get it.

[Effects of the Invention] According to the rolling plate deformation resistance measuring method of the present invention, it is possible to easily and accurately measure the rolling plate deformation resistance online without relying on the experience or intuition of a worker. It is possible to accurately adjust the work roll gap of the rolling mill in the subsequent stage, and as a result, it is possible to save labor on the rolling line and improve the strip thickness accuracy.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of the present invention, FIG. 2 is a side view for explaining the principle for obtaining the projected contact length in the present invention, and FIG. 3 is for obtaining a deformation resistance in the present invention. 4 is a side view for explaining the principle of FIG. 4, FIG. 4 is a graph showing the relationship between the forward tension and the high-speed-side advance rate when different speed rolling is performed using a strip, and FIG. 5 is a graph showing the forward tension and rolling load. It is a graph showing a relationship. In the figure, 1 is a low speed work roll, 2 is a high speed work roll, 3 is a load detector, 4,5 is a tension detector, 6 and 7 are plate thickness detectors, and 8 is a calculator.

Continuation of the front page (56) References JP-A-57-22812 (JP, A) JP-A-56-163017 (JP, A) Edited by the Iron and Steel Institute of Japan, Joint Study Group, left extension, theoretical section Actually ”Japan Iron and Steel Institute (September 1, 1984) PP. 45-47

Claims (1)

[Claims] 1. A rolling method for performing different speed rolling by passing a plate between a low speed side work roll and a high speed side work roll without winding the plate, and detecting the rolling load and the front and rear tensions of the rolled plate. The following formula is used to detect the inlet side thickness and the outlet side thickness of the rolled plate, or to set the inlet side thickness of the rolled plate and detect the outlet side thickness. A method for measuring the deformation resistance of a rolled plate, which is characterized in that the deformation resistance of the rolled plate is determined online by using the.