JPH024365B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a groove rolling mill that uses groove rolls to roll a billet into a steel bar or wire rod of a predetermined size. The present invention relates to a control method for keeping constant the deviation between the widthwise dimension of a material and the widthwise dimension of a rolled material on the exit side of a stand.

[Technical background of the invention and its problems]

Generally, steel bars or wire rods are continuously rolled by rolling mills equipped with slotted rolls. This groove rolling mill is a tandem mill consisting of many types of grooves, and the typical groove types are diamond hole type, square hole type, hexagonal hole type, oval hole type, and round hole type. By sequentially passing a billet as a rough material through these holes, a steel bar or wire rod as a final product can be obtained.

In this case, rolling with slotted rolls is different from rolling, which mainly involves two-dimensional deformation, such as sheet material, because rolling with grooved rolls mainly involves three-dimensional deformation, and rolling is performed sequentially in a direction perpendicular to the material to be rolled. Therefore, sufficient rolling theory for calculating various rolling characteristic values has not been established, and rolling setting calculation and control are also areas of rolling technology that require further improvement in the future.

Figure 1 shows the cross-sectional shape of the rolled material passing through the i-1 stand with an oval hole type and the i-stand with a round hole type. When the material is caught between the rolls of the i-1 stand, the rolling direction dimension H _i-1 indicated by the arrow in b becomes smaller than the diameter D, and at the same time, the direction perpendicular to the rolling direction (hereinafter referred to as the width direction) becomes smaller than the diameter D. The dimension B _i-1 of The dimension B _i is narrower than the width direction dimension B _i-1 on the exit side of the i-1 stand, and conversely, the width direction dimension H _i is wider than the rolling direction dimension H _i-1 on the exit side of the i-1 stand, The aim is to obtain a circular cross section as a result.

In such rolling using grooved rolls, it goes without saying that changes in width direction dimensions must be considered at the same level as changes in rolling direction dimensions, as is the case with the rolling example shown in FIG.

However, in conventional groove rolling, the mill configuration is complicated, such as alternating horizontal stands and vertical stands, and the tolerance range for product accuracy becomes loose when the intended use is taken into consideration. For these reasons, even if the tension between the stands is controlled, active dimensional control is hardly performed, and the quality is inferior to that of plate materials.

[Purpose of the invention]

The present invention was made in consideration of the above circumstances, and
The object of the present invention is to provide a new control method for a groove rolling mill that can control dimensions in the width direction of a steel bar or wire rod at the same level as in the rolling direction.

[Summary of the invention]

In order to achieve the above object, the method for controlling a groove rolling mill of the present invention provides a method for controlling a groove rolling mill in which an adjacent i-1 stand and an i-stand each equipped with groove rolls roll a material to be rolled from substantially orthogonal directions. , i-
1 stand and i stand roll gap,
Also, the ratio of the dimension in the rolling direction and the dimension in the width direction of the rolled material on the exit side of the i-stand is set, and
The rolling loads of the 1-stand and the i-stand are detected, and based on these set values and detected values, the widthwise dimension of the rolled material on the entrance side of the i-stand and the widthwise dimension of the rolled material on the exit side of the i-stand are calculated. The method is characterized in that the deviation is calculated and the rolling loads of the i-stand and i-1 are controlled so that the deviation becomes a predetermined value.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

Figure 2 shows the i-1 stand and the i-stand extracted from the rolling mill group, and when the rolled material 1 is rolled by the rolling roll R _i-1 of the i-1 stand shown as a vertical roll. rolling load of
P _i-1 is the dimension in the rolling direction of the rolled material 1 after rolling.
H _i-1 , this width direction dimension is B _i-1 , and the rolling load when the rolled material 1 is rolled by the rolling roll R _i of the i stand shown as a horizontal roll is
P _i , the dimension in the rolling direction after rolling is B _i , and the dimension in the width direction is H _i .

Also, the Mill constant of the i-1 stand is M _i-1 , i
Let M _i be the mill constant of the stands, and let S _i-1 and S _i be the roll gap settings of these stands, respectively. However, since these rolls have a hole shape, this roll gap refers to the maximum value of the roll gap as shown in FIG.

Assuming this, in the i-1 stand, the following relationship is established by using the well-known basic gauge meter equation.

H _i-1 =S _i-1 +P _i-1 /M _i-1 (1) Furthermore, in the i-stand, the following relationship holds true.

B _i =S _i +P _i /M _i …(2) On the other hand, the rolling direction dimension H _i-1 on the exit side of the i-1 stand
is the width direction dimension of the i-stand entrance side, and furthermore, the width direction dimension of the i-stand exit side is H _i , so that the following relationship holds between these.

H _i =H _i-1 +ΔH _i (3) Here, ΔH _i is the amount of expansion in the width direction due to rolling by the i-stand.

At this time, if α is the ratio of the widthwise dimension H _i on the exit side of the i-stand and the rolling direction dimension B _i , it can be expressed as α=H _i /B _i (4).

α shown in equation (4) must be maintained at an appropriate value for each stand. For example, when a round bar is obtained using stand i as the final stand, α becomes 1.

The following equation is obtained from equations (1), (2), (3), and (4) above.

ΔH _i =α(S _i +P _i /M _i )−(S _i-1 +P _i-1 /M _i-1 )...(5) The present invention uses this equation (5) to determine the width of the rolled material. Directional dimension control is to be performed, and FIG. 4 shows the configuration of a control system for implementing this width direction dimension control.

In the same figure, the rolling roll of the i-2 stand
R _i-2 and the rolling roll R _i of the i stand are horizontal rolls, and the rolling roll R _i-1 of the i-1 stand between them is a vertical roll, but for convenience, it is shown as a horizontal roll like the other stands. It's dark.

Here, the i-1 stand is provided with a load detector 21 that detects the rolling load, a rolling down device 31 that adjusts the roll gap, and a rolling down control device 41 that specifically controls this rolling device 31. Similarly, the i-stand is provided with a load detector 22 for detecting the rolling load, a rolling down device 32 for adjusting the roll gap, and a rolling down control device 42 for specifically controlling the rolling down device 32.

The i-2 stand also includes an electric motor 70 that drives the rolling roll R _i-2 , a tachometer 80 that detects the speed of the electric motor 70, and a computer 1 that will be described later.
A speed control device 90 that controls the electric motor 70 in response to a signal of The i-stand is also provided with an electric motor 72, a tachometer 82, and a speed control device 92.

In addition, each of the above-mentioned components is directly or indirectly connected to the computer 10, and the rolling schedule, speed standard,
A setting device 11 that sets the inter-stand tension, etc., and a dimension meter 5 that measures the dimensions of the rolled material on the exit side of the i-stand.
Further, a delay circuit 6 is provided between the load detector 21 of the i-1 stand and the calculator 10 to ensure a dead time in inverse proportion to the rolling speed.

The operation of the rolling control device configured as described above will be explained below in relation to the principle equations (1) to (5).

First, S _i-1 and S _i in equation (5) are, respectively,
This is the setting value of the roll gap of the i-1 stand and the i-stand, and when the calculator 10 applies a control signal to the rolling reduction control devices 41 and 42 according to the rolling schedule by the setting device 11, this rolling reduction control device 41 drives the rolling reduction device 31. and the reduction control device 4
2 drives the rolling down device 32 to set the roll gap. Furthermore, M _i-1 and M _i in equation (5) are the Mill constants of the i-1 stand and the stand, respectively, and these values are stored in the calculator 10 in advance. Furthermore, α in equation (5) is a constant determined by the dimensions and shapes of the grooved rolls R _i-2 , R _i-1 , R _i , etc. and the rolling schedule. When a stand is used and a round steel bar is used as a product, it is desired that the dimension B _i in the rolling direction and the dimension H _i in the width direction be completely equal, so α=1.

By the way, dimensional fluctuations on the roll exit side of the rolled material 1 are caused by dimensional fluctuations or irregularities on the roll entry side,
This is also due to differences in deformation resistance due to temperature distribution of the rolled material 1, etc., and can ultimately be interpreted as a variation in rolling load.

Therefore, controlling ΔH _i in equation (5) means i
It is nothing but controlling the width direction dimension H _i of the exit side of the stand, and if the rolling loads P i-1 and P _i of the i _-1 stand and the i stand are controlled simultaneously, ΔH _i can be kept at a predetermined value. can be controlled.

Therefore, the rolling load P _i-1 of the i-1 stand is detected by the load detector 21, and this detection signal is taken into the computer 10 via the delay circuit 6 and is calculated by the i-1 according to the above equation (1). −1 The dimension H _i-1 in the rolling direction on the exit side of the stand is calculated. Note that the delay circuit 6 is i-1
This guarantees the time it takes for the part rolled on the stand to reach the i-stand, and actual calculations are performed after this dead time.

At the same time as calculating equation (1), the calculator 10 calculates that the deviation ΔH i between the width direction dimension on the entrance side of the i stand and the width direction dimension on the exit side is a predetermined _α according to the equation (5). A rolling load P _i of the i-stand that satisfies the following is calculated, and a control signal to obtain this rolling load is applied to the rolling control device 42 of the i-stand. Next, this rolling down control device 42 drives the rolling down device 32 to control the roll gap S _i .

Therefore, the rolling load P _{i-1 of stand i-1} and i
By simultaneously controlling the rolling load P _i of the stand, ΔH _i can be controlled to a predetermined value.

Although it is not essential for the above-mentioned rolling control, this type of rolling mill is provided with a size gauge 5 at some position. Therefore, this dimension meter 5
If it is installed on the exit side of the i-stand as shown in Figure 4, it becomes possible to perform the above control while detecting the dimensions of the i-stand exit side, thereby further improving product accuracy. can be done.

Further, in the above control process, the advance rate or mass flow of the rolled material 1 changes, and the rolling speed and tension between the stands also change accordingly, but these changes are controlled by the speed control device 91 of the i-1 stand. The electric motor 71 and the electric motor 72 are each controlled by the speed control device 92 of the i-stand, so that the electric motor 71 and the electric motor 72 are continuously operated so as to always satisfy the speed standard set in the setting device 11. Conventional techniques may be used for these controls.

Furthermore, in the above embodiment, the simplest gauge meter basic equations such as equations (1) and (2) are used, but oil film correction due to rotational speed changes, thermal expansion correction of rolling rolls, wear correction, etc. Substantially the same control as described above can be performed using an equation incorporating .

In addition, even if the rolling load is controlled by controlling the tension between the stands by controlling the rotational speed of the rolling rolls,
The dimensions of the exit side of the stand can be controlled in the same way as described above.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the rolling characteristics of adjacent stands are simultaneously used, taking into full consideration the characteristics of continuous rolling using grooved rolls, and the rolling direction dimension and width direction dimension are Since the ratio is controlled to be kept constant, steel bars and wire rod products with high dimensional accuracy can be obtained.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram for explaining the rolling state of a general groove rolling mill, Fig. 2 is a schematic diagram for explaining the basic principle of the present invention, and Fig. 3 is a schematic diagram for explaining the basic principle of the present invention. FIG. 4 is a block diagram showing the configuration of a rolling control system for implementing the present invention. 1... Rolled material, 21, 22... Load detector,
31, 32... Rolling down device, 41, 42... Rolling down control device, 5... Dimension meter, 6... Delay circuit, 70,
71, 72... electric motor, 80, 81, 82... tachometer, 90, 91, 92... speed control device,
10... Calculator, 11... Setting device, R _i , R _i-1 ,
R _i-2 ...Perforated roll.

Claims (1)

[Scope of Claims] 1. In a method for controlling a groove rolling mill in which adjacent stands are each equipped with groove rolls and these groove rolls roll a material to be rolled in substantially orthogonal directions, and the roll gap of the i-stand, and the ratio of the dimension in the rolling direction and the dimension in the width direction of the rolled material on the outlet side of the i-stand, and also detect the rolling loads of the i-1 stand and the i-stand, and set these set values. Based on the detected values, the deviation between the width direction dimension of the rolled material on the entrance side of the i-stand and the width direction dimension of the rolled material on the exit side of this i-stand is calculated, and the deviation is adjusted to a predetermined value. , an i-stand and an i-1 stand. 2 Set the roll gap setting value of i-1 stand.
S _i , the mill constant is M _i , the rolling load is P _i , the setting value of the roll gap of the i stand is S _i-1 , the mill constant is
M _i-1 , the rolling load is P _i-1 , and the ratio of the dimension in the rolling direction and the dimension in the width direction of the material to be rolled on the exit side of the i-stand is set as α, and the value of the material to be rolled on the entrance side of the i-stand is The deviation ΔH _i between the width direction dimension and the width direction dimension of the rolled material on the exit side of this i-stand is calculated using the following formula ΔH _i = α(S _i +P _i /M _i )−(S _i-1 +P _i-1 / The method for controlling a groove rolling mill according to claim 1, characterized in that the calculation is performed using M _i-1 ).