JPH0256963B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for accurately controlling dimensions when rolling a wire or bar using a block mill having a fixed speed ratio and a multi-stage stand connected to a single electric motor and driven by a common drive. This type of block mill requires less space to install the mill compared to the large number of stands provided, and the rolls are cantilevered, so
This has the advantage that the number of man-hours required for roll change is small. On the other hand, because it is a common drive, the speed ratio of each stand is fixed by the gear ratio,
A disadvantage is that the speed ratio between the stands, and therefore the inter-stand tension, cannot be adjusted. On the other hand, in recent years, requirements regarding dimensional accuracy have become stricter even in the rolling of wire rods or bars, and wire rods with high dimensional accuracy that can omit drawing in secondary processing are being developed. Conventionally, as a method for controlling the dimensions of wire rods, there was
−128469 “Dimension control method in wire rod rolling” Utilizing the theory of the influence coefficient of continuous rolling, the product vertical dimension (dimension in the rolling direction of the final stand) measured at the rear of the block mill is changed from the target value. By adjusting the roll gap of the final stand in proportion to the deviation from the target value, the No.
A method of controlling feedback by adjusting the roll gap of one stand (first stand) is known. However, the finishing speed of recent finishing block mills is 60 to 100 m/min when the wire diameter is 5.5φ.
s, the length of the material rolled without control during feedback reaches several tens of meters in finished size, making it difficult to apply in practice. It is an object of the present invention to provide a method for overcoming these difficulties and performing rolling with high dimensional accuracy over the entire length of the coil. The gist of the present invention will be described below using FIG.
In this figure, 1, 3, 5, 7, and 9 are the vertical rolls of the finishing vertical mill, 2, 4, 6, 8, and 10 are the horizontal rolls, 11 is the drive motor common to these, 12 is the gearbox, and 13 is the It is a rolled material. 14 is a thermometer that measures the material (rolled material) temperature To; 15 is a dimension meter that measures the material's vertical dimension Ho; 16 is a dimension meter that measures the material's left-right dimension Bo; 17 is the product's vertical dimension h (10) A dimension meter 18 is a dimension meter that measures the left and right dimension b (10) of the product. Also 19~
23 and 29 are arithmetic units, 24 to 28 are temperature or dimension target value setting devices, and 30 and 31 are reduction devices. The calculation devices 19 to 23 and 29 compare the measured values and the target values from the target value setters 24 to 28 to calculate the deviation and determine the required change in the roll gap at the final stand 1 according to the deviation. The amount is calculated. To _r , H _r , B _r are the material temperatures;
Indicates the target values for the vertical and horizontal dimensions, h _r (10),
b _r (10) indicates the target values for the product's top and bottom dimensions and left and right dimensions. Further, the dotted line indicates the feedback control system, and the solid line indicates the feedback control system. Here, the roll rolling direction of each stand in the block mill is called the vertical direction. Therefore, for example, in a mill where the No. 1 stand consists of a pair of vertical rolls, followed by a pair of horizontal rolls and then a pair of vertical rolls,
For stands No. 1, 3, 5, 7, and 9, the horizontal direction is the vertical direction, and the vertical direction is the left and right directions.
On the other hand, for No. 2, 4, 6, 8, and 10 stands, the vertical direction is the top and bottom, and the horizontal direction is the left-right direction. In the present invention, firstly, the material temperature at the front part of the material is measured in front of the block mill.
Let To, the material's top and bottom dimensions Ho, and the material's left and right dimensions Bo be their target values To _r , _Hor , and _Bor . Second, the roll gap SR of the final stand is adjusted so that the deviation from the target value h _r (10) of the product vertical dimension h (10) of the front section measured at the rear of the block mill is 0.
By changing (10) by the amount determined from the influence coefficient BH1 (10, 10, 3) = 1, and by using the same method for the product left and right dimension b (10), the roll gap SR (1) of No. 1 stand is calculated. By changing the value, feedback control is performed and preset is performed. Thirdly, for rolling from the front part to the middle part and the tail part, the target values To _r of the measured material temperature To, material vertical dimension Ho, material left and right dimension Bo,
Deviation from Ho _r and Bo _r and each product's left and right dimensions b (10)
The influence coefficient BB (10, 1, 1), BB (10,
1, 2), the amount determined from the influence coefficient BB (10, 1, 3) of the No. 1 stand reduction by the amount that cancels out the sum of the variations in the left and right dimensions of each product determined from BB (10, 2, 2) Feedforward control is performed by changing the roll gap SR(1). At this time, the product vertical dimension h(10) is not controlled because its variation is small. Here, since it is not possible to control the cumulative deviation of the product vertical dimension h (10) and the product lateral dimension b (10) from the target values by feed forward control alone, in addition to this, the product vertical dimension h (10) Regarding (10), the roll gap of the final stand is
SR (10), and No. 1 for product left and right dimensions.
This is compensated for by performing feedback control to adjust the roll gap SR(1) of the stand in the same manner as described above. In this way, the present invention has an influence coefficient of the material temperature To.
Feedback control takes BB10, j, 1, j = 1, 2 into consideration, resulting in good accuracy and responsiveness.In addition, since the accumulation of deviations due to errors in feedforward control is compensated for by feedback control, the overall length of the coil is reduced. Its feature is that stable dimensional control is possible over a wide range. Below, the influence coefficient, control method, and examples will be explained in detail for the 5.5φ finished material. First, let's talk about the influence coefficient. Material temperature, material top and bottom dimensions, material left and right dimensions are each target value To = 850
Table 1 shows the initial values of the rolling conditions when ℃ and Ho=Bo=17.1φ.

[Table] Using this rolling condition as the reference rolling condition for the influence coefficient, the formulas (1) to (5) show the definition of the influence coefficient when the independent variable Y (j, k) changes as shown in Table 2. . BH1 (j, j, k) = ΔH ₁ (i) / H ₁ (i) / ΔY (i
,k)/Y(i,k)...(1) Y(j,k): Independent variable H ₁ (i): Exit height BB(i,j,k)=ΔB ₁ (i)/B ₁ (i)/ΔY(i
, k)/Y(i, k)...(2) B ₁ (i): Exit width BTF(i, j, k) = Δt _f (i)/k _fn (i)/ΔY(
i, k)/Y(i, k)...(3) tf(i): Forward tension BV0(i, j, k)=Δv _b (i)/v _b (i)/ΔY(i
, k)/Y(i, k)...(4) vb(1): 1 stand entrance speed BF(i, j, k) = Δf(i)/1+f(i)/ΔY(
i, k)/Y(i, k)...(5) f(i): Advanced Subscript i: Stand No. of dependent variable. j: Stand No. of independent variable, etc. k: Classification No. of 〃 Table 2 reference

[Table] In this case, it has been confirmed by theory and experiment that if the amount of change in Y(j,k) is small and is about the value shown in Table 2, the value of the influence coefficient hardly changes and is linear. Further, even if the reference rolling conditions change within the range of dimensional control, the change in the value of the influence coefficient is minute and may be kept as a constant value in practice. Here, the method of calculating the influence coefficient in the present invention was determined as follows. A nonlinear equation consisting of a unit model of deformation, load, and temperature is solved to quantitatively determine the rolling characteristics (dimensions, rolling load, torque, power, and temperature of the rolled material) under standard conditions, and the amount of change in rolling conditions thereafter is minute. The rolling characteristics after the change were determined by linear calculation, and the influence coefficient was determined by dividing the rate of change of both by the independent variable. On the other hand, Japanese Patent Publication No. 54
The method for calculating the influence coefficient in -128469 is to linearize the deformation model (width spread, advance, cross-sectional area) assuming that the mill stiffness is so large that it does not affect dimensional changes, and then use this and the continuity equation to calculate the influence coefficient. I'm looking for. The features of the theoretical calculation in the present invention are that although the calculation method is complex, it takes into consideration the effect of temperature on dimensions, and that it is possible to quantitatively calculate the standard rolling conditions and changed rolling conditions with high accuracy. , the influence coefficient is also more accurate than the value in the prior patent. Therefore, in the present invention, since the initial values of the rolling conditions shown in Table 1 are determined with high accuracy through theoretical calculations, when the material temperature, material vertical dimension, and material horizontal dimension are each target value, the product dimension is determined to be the target value. When performing feedback control to achieve this, the amount of adjustment of the roll gaps of the final stand and No. 1 stand is minute, and the presetting of the material front part is done in a short time. Next, we will discuss the accuracy of the influence coefficient and a calculation example. The effect of material diameter on width (large material diameter) is the second
Figure a shows the effect of No. 1 stand reduction on the width (No.
Fig. 2b shows the effect of No. 5 stand reduction on the width (No. 5 strong reduction), Fig. 2 c shows the effect of No. 5 stand reduction on the width,
Figure 2d shows the effect of stand reduction on the stand width (No. 9 strong reduction), and Figure 3 shows the effect of each stand reduction (strong reduction) on the finished width (product lateral dimensions). △′ is the model of JP-A-54-128469,
▲′ is the actual measured value (lead) of JP-A-54-128469, and the 〇 mark is for this model. Here, the model in the present invention was compared with the model in JP-A-54-128469 and actual values in lead rolling. The model of the present invention has good agreement with actual measured values, has a large influence coefficient of the material diameter, No. 1 stand, No. 9 stand, and final stand reduction on the product's left and right dimensions, and has a large influence coefficient on the product's left and right dimensions. It can be seen that the influence coefficient is small. Table 3 shows the influence coefficients of material temperature, material vertical dimensions, and horizontal material dimensions on the vertical dimensions, horizontal dimensions, forward tension, No. 1 stand entry speed, and advancement of each stand of each stand.

【table】

【table】

【table】

[Table] Under this standard rolling condition, the influence coefficient of the material temperature To on the product dimensions is as follows: When To changes from 850 to 800℃, the product top and bottom dimensions are BH1 (10,
1, 1) = -0.030, BB for product left and right dimensions
(10, 1, 1) = -0.238. Also, To=850
→The influence coefficient when changing to 900℃ is BH1 (10,
2, 1) = -0.024, BB (10, 2, 1) = 0.500. Therefore, it can be seen that under these rolling conditions, the influence of the material temperature on the vertical dimensions of the product is minute, but the influence on the horizontal dimensions of the product cannot be ignored. Next, a presetting method using feedback control and a dimensional control method using feedback control will be described. A method for presetting the top and bottom dimensions of the product using feedback control is shown in FIG. 4a, and a method for presetting the lateral dimensions of the product is shown in FIG. 4b. The product vertical dimensions are determined by the deviation between the initial value h ₀ (10) and the target value h _r (10) in state 0, and the influence coefficient BH1 of the final stand reduction.
Control is performed to state 1 based on the roll gap change amount of the final stand determined from (10, 10, 3)=1. In other words, the roll gap at the final stand is h ₁ (10) = h _r (10) ……(6) SR ₁ (10) = SR ₀ (10) + h ₁ (10) − h ₀ (10) ……(7 ) is determined by Here, h ₀ (10), h ₁ (10), h _r
(10) are the initial value, preset value, and target value of the product top and bottom dimensions, respectively, and SR ₀ (10) and SR ₁ (10) are the initial value and preset value, respectively, of the final stand roll gap. The product left and right dimensions are the target values b _r (10) in condition 1.
and the influence coefficient of the rolling reduction of No. 1 stand.
Control is performed to state 2 based on the No. 1 stand roll gap change amount determined from BB10, 1, and 3. Here, product left and right dimensions b ₁ (10) in condition 1, No. 1 in condition 2
The stand roll gap SR ₂ (1) is determined by equations (8) to (10). b ₁ (10) = b ₀ (10)・(1+BB10,10,3)・(
SR ₁ (10) - SR ₀ (10)) / h ₀ (10)) ... (8) b (10) = b _r (10) ... (9) SR ₂ (1) = SR ₁ (1) +h ₁ (1)・(b ₂ (10)−
b ₁ (10)) / BB (10, 1, 3)・b ₁ (10)……(10) Product vertical dimension h ₂ 10 in condition 2 is h ₂ (10)=h ₁ (10)・(1+BH1 (10,1,3)
・(SR ₂ (1) - SR ₁ (1))/h ₁ (1))...(11) Since BH1 (10, 1, 3) = 0.0368, h ₂
(10) It turns out that h ₁ (10). In the above, when the material temperature at the front part of the material, the material top and bottom dimensions, and the material left and right dimensions are set to the target values To _r , H _r , and _Bor , the product top and bottom dimensions and the product left and right dimensions are set to the target values h _r (10), b _r
(10), the rolling conditions are preset from the initial values of state 0 to state 2 by feedback control. Next, during rolling from the front section to the middle section and tail section, the material temperature To
→To＋ΔTo, material vertical dimension is Ho→Ho＋ΔHo,
We will discuss the dimension control method when the left and right dimensions of the material change from Bo to Bo + ΔBo. Figure 5a shows the influence of material temperature on the product's vertical dimensions, and Figure 5b shows the influence of material temperature on the product's lateral dimensions. The product dimensions in state 3 (To + ΔTo, Ho, Bo) are determined by equations (12) and (13). h ₃ (10) = h ₂ (10)・(1+BH1(10,1,1)
・ΔTo／To……(12) b ₃ (10)=b ₂ (10)・(1+BB(10,1,1)・
ΔTo/To...(13) Figure 5c shows the influence of the material vertical dimension on the product vertical dimension, and Figure 5d shows the influence of the material vertical dimension on the product lateral dimension. State 4 (To+ΔTo, Ho
The product dimensions at +ΔHo, Bo) are determined by equations (14) and (15). h ₄ (10) = h ₃ (10)・(1+BH1(10,1,2)
・ΔHo/Ho)……(14) b ₄ (10)=b ₃ (10)・(1+BB(10,1,2)・
ΔHo/Ho)...(15) Figure 5e shows the influence of the left and right dimensions of the material on the top and bottom dimensions of the product, and Figure 5f shows the influence of the left and right dimensions of the material on the left and right dimensions of the product. State 5 (To + ΔTo, Ho
The product dimensions at +ΔHo, Bo+ΔBo) are expressed by formula (16),
Determined by (17). h ₅ (10) = h ₄ (10)・(1+BH1(10,2,2)
・ΔBo/Bo)……(16) b ₅ (10)=b ₄ (10)・(1+BB(10,2,2)・
ΔBo/Bo)...(17) As described above, the product dimensions change to h ₅ (10) and b ₅ (10) in state 5 due to the disturbances ΔTo, ΔHo, and ΔBo. Therefore, the deviation from the target value h _r (10) b _r (10) of product dimensions and the influence coefficient BB (10, 1,
It is necessary to control the product's left and right dimensions to the target value using feed forward control that changes the roll gap of the No. 1 stand by an amount determined from 3). Here, the roll gap SR ₆ (1) and product height h ₆ (10) of No. 1 stand in state 6 are calculated by formulas (18), (19), (2
0), (21). b ₆ (10)=b _r (10) ……(18) SR ₅ (1)=SR ₂ (1) ……(19) SR ₆ (1)=SR ₅ (1)+h ₁ (1)・( b ₆ (10)−
b ₅ (10)) / BB (10, 1, 3)・b ₅ (10)……(20) h ₆ (10)=h ₅ (10)・(1+BH(10, 1, 3)・
(SR ₆ (1) - SR ₅ (1)) / h ₅ (1))...(21) Material Once controlled within the acceptable range,
The measured values of the material temperature, vertical dimension, and left and right dimensions at the entrance side of the block mill for that part of the material are set as target values,
Feedforward control is started using the deviation of the measured values of the material temperature, vertical dimension, and horizontal dimension at the entrance side of the block mill from the target values and the influence coefficient. Therefore, although feed forward control is not performed for a portion of the front portion of the material, that portion is extremely small within the total length of the material. A method for controlling the left and right dimensions of the product to state 6 in this manner is shown in FIG. 5h. In this case, the change in the vertical dimensions of the product is minute from state 3 to state 6, and there is no need for feedforward control. In the case of feedback control, it is ineffective against the cumulative deviation of product dimensions from the target value, so it is necessary to use a method similar to the preset method to compensate for this. . In this way, the rolling from the preset to the tail section is controlled by feed forward control +
Feedback control allows stable control of product dimensions. Next, examples will be described. 0.06% C steel, cold finishing dimension 5.5φ, finishing speed
For 60m/s, target value of material temperature To = 850
Table 4 shows an example of the presetting method using feedback control when the target value Ho=Bo=17.1 of material dimensions is shown in Table 4, and Table 5 shows the feedback control method for disturbances ΔTo, ΔHo, and ΔBo.

[Table] *1: Changes between each procedure
0.06%℃ steel, 60m/s at 5.5〓, entrance temperature T ₀ = 850℃
Entrance side top and bottom, left and right dimensions H ₀ = B ₀ = 17.10mm

[Table] In this case, since feedforward control is performed, the uncontrolled product length is determined by the speed of change of the roll gap, and is 6 m at a finishing speed of 60 m/s.
The length is approximately 10 m at 100 m/s, which is considerably shorter than conventional control methods, and dimensional fluctuations can be controlled within an allowable range over the entire length of the coil.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a method for controlling dimensions in a common drive block mill of the present invention. FIG. 2 is a diagram showing the influence coefficients of the material diameter, No. 1 stand reduction, No. 5 stand reduction, and No. 9 stand reduction on the left and right dimensions of each stand. FIG. 3 is a diagram showing the influence coefficient of each stand reduction on the left and right dimensions of the product. FIG. 4 is a diagram showing a presetting method using feedback control. Figure 5 shows the influence of disturbances of material temperature ΔTo, material vertical dimension ΔHo, material horizontal dimension ΔBo on product vertical dimension, product horizontal dimension, and No. 1 stand roll gap as the manipulated variable, and the product is manufactured by feed forward control. It is a figure which shows the method of controlling a left-right dimension. In the drawing, 1, 3, 5, and 9 are hard rolls of the common drive block mill, 2, 4, 6, 8, and 10 are the same horizontal rolls, 13 is the material to be rolled, To, Ho, and Bo are the material temperatures at the front stage of the block mill, The top and bottom dimensions, left and right dimensions, h(10) and b(10) are the top and bottom dimensions and left and right dimensions of the rolled product in the latter stage of the block mill, To _r ,
H _r and B _r are the target values for the material temperature, top and bottom dimensions, and left and right dimensions, and h _r (10) and b _r (10) are the target values for the product top and bottom dimensions and left and right dimensions.

Claims (1)

[Scope of Claims] 1. When rolling a wire or bar by a common drive block mill consisting of a multi-stage stand in which sets of rolling rolls whose axes intersect with each other at 90 degrees are arranged alternately, the block mill On the entry side of the block mill, measure the temperature of the material, the vertical dimension of the material (dimension in the direction of roll reduction at the first stand of the block mill), and the horizontal dimension of the material (dimension in the direction perpendicular to the direction of roll reduction at the first stand of the block mill). , At the exit side of the block mill, measure the vertical dimension (dimension in the direction of roll reduction at the final stand) and lateral dimension (dimension in the direction perpendicular to the direction of roll reduction at the final stand), and measure the front part of the material (front dimension). Regarding part), the measurement result of the vertical dimension of the rolled product measured at the exit side of the block mill was compared with the target vertical dimension of the rolled product, and in order to reduce the deviation to zero, the size of the roll gap at the final stand of the block mill was determined. In addition to performing feedback control using the manipulated variable, the measurement result of the horizontal dimension of the rolled product measured at the exit side of the block mill is compared with the target horizontal dimension of the rolled product, and in order to reduce the deviation to zero, Feedback control is performed using the size of the roll gap as the manipulated variable, and then, regarding rolling to the tail end of the material, the temperature of the material at the front part of the material measured at the entry side of the block mill, and the vertical dimensions of the material are measured. The values of the left and right dimensions of the material are set as target values, and based on the deviation from the target values, the roll gap at the first stand of the block mill is set as the manipulated variable, and feedforward control is performed that takes into account the influence of material temperature. Compare the vertical dimension of the rolled product measured at the exit side of the block mill with the target vertical dimension of the rolled product, and perform feedback control using the size of the roll gap at the final stand of the block mill as the manipulated variable in order to reduce the deviation to zero. , Compare the lateral dimension of the rolled product measured at the exit side of the block mill with the target lateral dimension of the rolled product inputted by the product lateral dimension target setter 28, calculate the deviation, and (8) to (10) It consists of calculating the required amount of change in the roll gap amount at the first stand using a formula, inputting the result to the rolling down device 30, and performing feedback control to change the roll gap amount at the first stand based on it. Dimension control method in wire rod rolling. b ₁ (10) = b ₀ (10)・(1+BB(10,10,3)・
(SR ₁ (10) - SR ₀ (10) / h ₀ (10))) ... (8) b ₂ (10) = b _r (10) ... (9) SR ₂ (1) = SR ₁ ( 1) +h ₁ (1)・(b ₂ (10)−b ₁ (10))/BB(10,
1, 3)・b ₁ (10)...(10) Here, b (10) is the product's left and right dimensions, h (10) is the product's top and bottom dimensions, subscript 0 is the initial value, subscripts 1 and 2 are the state 1, 2. The subscript r is the target value, BB, BH are the influence coefficients,
SR(10) and SR(1) indicate the final and No. stand roll gaps.