JPH02121703A - Method for rolling width directional tapered plate - Google Patents

Abstract

PURPOSE:To manufacture a steel sheet having a width directional taper being a target value and no camber by rolling a rolled stock by bringing a required roll axis slant amount to be a specific target roll axis slant amount for manufacturing a steel sheet having different thickness in the width direction by rolling a stock with a prescribed thickness. CONSTITUTION:In the spreading final pass, a taper varying ratio is minimized in a 1st pass by giving an inlet side taper in a 1st finish pass to prevent generation of cambers and crop uneven elongation. A target roll axis slant amount Si is decided by the equation I in respective passes of finish rolling to minimize generation of cambers in an allowable range, not to conflict with a roll axis slanting limit for a device, and to obtain a target taper. Then, high sheet thickness accuracy is attained by canceling a roll axis slant and a predicted error of a slant value by concurrently performing automatic control of both a sheet thickness and a taper value during rolling.

Description

[Detailed Description of the Invention] [Industrial Application Field] When using a metal plate as a structural member, there are many cases in which the required strength differs depending on the part, and in such cases, a plate with partially varying thickness is used. May be required. Specifically, such variable thickness metal plate products include differential thickness plates in the shape of connecting flat plates with different thicknesses as shown in Figure 1 (see figure (a)
)), a tapered plate whose thickness changes obliquely in the longitudinal direction of rolling ((b) in the same figure), and a widthwise taper plate whose thickness changes obliquely in the width direction ((c) in the same figure), etc. There is.

The present invention relates to a method of rolling a widthwise tapered plate in which the thickness changes in an inclined manner in the width direction.

[Conventional technology]

As a rolling method for the width direction taper plate, for example, Japanese Patent Application Laid-Open No. 49-53555 and Japanese Patent Application Laid-Open No. 49-74150 are used.
The method described in the publication No. 1 is known.

Japanese Patent Laid-Open No. 49-53555 proposes the following two methods for manufacturing a widthwise tapered plate with less camber.

■ A rolling method in which an initial taper is applied in the final pass for tentering, and then inclined rolling in the width direction is performed at a constant reduction rate (the reduction rate on the thicker and thinner sides is equal in each pass).

However, rolling reduction ratio = rolling reduction amount/inlet side plate thickness.

■ A rolling method in which an initial taper is applied in the final pass for tentering, and then inclined rolling is performed in the width direction with a constant reduction amount (equal reduction amounts on the thicker and thinner sides in each pass).

Furthermore, in JP-A-49-74150, the constant reduction amount rolling method is improved, and the thick side plate thickness/thin side plate thickness of the starting material is made larger than the thick side plate thickness/thin side plate thickness of the target product. A method has been proposed in which camber toward the thinner side occurs in the upstream pass of rolling to offset the camber toward the thicker side that occurs near the final pass.

On the other hand, regarding a plate thickness control method when the target plate thicknesses on the left and right sides are different, for example, in Japanese Patent Application No. 11tO-270581, AGC (automatic plate thickness A method has been proposed in which the plate thickness on each side is independently controlled during rolling using a control system.

Furthermore, in the field of section steel rolling, rolls with different diameters in the axial direction are generally used to manufacture products with different thicknesses in the width direction.

[Problem to be solved by the invention]

However, the above method had the following problems.

In the constant reduction rolling method described in JP-A No. 49-53555, in order to achieve the same reduction ratio as in the finishing pass in the upstream pass of rolling a thick plate, the rolling rolls must be tilted beyond the equipment limit. There may be cases where it is necessary to Further, in the constant reduction amount rolling described in the publication, since the elongation on the drive side and the work side in each pass are necessarily different, it is clear that the occurrence of rolling camber cannot be avoided in principle. Note that the inclination limit of the roll on the equipment referred to here refers to the uneven contact (partial metal (contact) or the maximum inclination of the rolling rolls without causing excessive stress concentrations. In a general thick plate rolling mill, the inclination limit of the rolls is about 10 to 30 mm as a left-right difference in the distance between the upper and lower roll axes at the roll chock position.

The method described in JP-A-49-74150 attempts to prevent the occurrence of camber during constant reduction rolling, but this method also has the following drawbacks.

■ In the upstream pass of rolling, that is, in the region where the plate thickness is thick, as shown in Figure 2 (al) and (a2), the taper ratio of the entry and exit sides [= taper (thickness deviation in the width direction) / width direction Changes in the average sheet thickness mainly affect abnormal changes in the front and rear crop shapes, not the camber.

In addition, in areas where the plate thickness is thin, Figure 2 (bl) and (bl)
A large camber occurs as shown in the figure. Therefore, even if a large taper is applied to the starting material, it is very difficult to generate a camber large enough to cancel out the camber generated near the final pass in the upstream pass. moreover,
Another drawback is that the crop at the leading and trailing edges increases, resulting in yield loss.

■ Generally, the left and right roll gap difference (per rolling width) does not match the taper. This is because the mill springs on the drive side and work side are different due to the difference in rigidity between the left and right housings of the rolling mill, the difference in the load acting on the housing, and the asymmetrical deflection of the rolling rolls caused by the asymmetric load distribution. Therefore, in order to achieve a predetermined taper with high precision, it is necessary to take these into consideration and accurately determine the amount of roll axis inclination. However, none of the above methods provides a method for determining the amount of roll axis inclination.

The method disclosed in Japanese Patent Application No. 60-270561 attempts to solve the problem (2) above, but this method was originally designed to roll a metal plate with a uniform thickness in the axial direction. The basic idea is the above-mentioned constant reduction rolling method. Therefore, if this method is used as is for rolling a tapered plate in the width direction, it becomes necessary to tilt the rolling rolls more than the equipment limit in the upstream stage of rolling, as in the constant reduction rolling method.

The method of imparting a widthwise taper using a taper roll, such as that used for shaped steel, requires the preparation of different taper rolls for each product size, which is disadvantageous in terms of cost. Furthermore, since the difference in the axial direction of the taper-roll gap is constant in each pass, the above-mentioned constant pressure rolling is impossible in principle, and the occurrence of camber is unavoidable.

(Means for Solving the Problems) The means of the present invention for solving the above problems are as follows.

(1) [1] When rolling a material with a predetermined thickness to produce a steel plate with different thicknesses in the width direction, taper rolling is performed in the tentering rolling direction in the final tentering pass to reduce the initial taper (difference in thickness in the width direction). [2] In the subsequent finish rolling,
The change in taper ratio (taper/width direction average plate thickness) on the inlet and outlet sides of each pass is within the taper rate change tolerance range, which is wide in thicker plate areas and narrower in thinner plate thickness areas. , and determine the target taper of each pass so that the inlet taper of each pass is at the lower limit of the allowable taper range determined from the outlet taper and the allowable taper rate change range, or a value close to the lower limit, and Required amount of inclination ΔS of the roll axis of the rolling roll in each pass to achieve the target taper
i is determined by solving the gauge meter equation regarding the average plate thickness and taper defined by the formula, and if the required roll axis inclination is within a pre-given tolerance range, the required roll axis inclination is the target. If the roll axis inclination amount exceeds the upper limit of the allowable range, the upper limit value is set as the target roll axis inclination amount, and if it falls below the lower limit of the allowable range, the lower limit value is set as the target roll axis inclination amount and rolling is performed. A rolling method characterized by obtaining a tapered plate in the width direction.

However, i: Pass No.

Sl: Average roll gap ΔSi: Δ5i )It Δt(i i ΔFi MTa, MDa.

B: W: ΔD: Left and right roll gap difference (per rolling width) Roll axis inclination amount (left and right of the distance between the axes of the upper and lower rolls at the chock position) Widthwise average plate thickness taper (widthwise plate thickness difference) Drive, workpiece Sum of rolling loads on the side drive, difference in rolling loads on the work side MTd, MDd: Coefficient (mill constant) Distance between roll chocks Rolling width Roll left and right diameter difference (2) When manufacturing different steel plates, taper rolling is performed in the tentering rolling direction in the final tentering pass to give an initial taper (difference in thickness in the width direction).[2] In the subsequent finish rolling, the entrance and exit sides of each pass are The change in the side taper ratio (taper/average thickness in the width direction) is within the allowable range of taper ratio change, which is wide in thicker areas and narrower in thinner areas, and The target taper of each pass is determined so that the side taper is at the lower limit of the allowable taper range determined from the exit taper and the allowable taper rate change range, or a value close to the lower limit, and the steps are taken to realize the target taper. The required amount of inclination of the rolling roll axis for each pass is determined by solving the gauge meter equation regarding the average plate thickness and taper specified by the formula, and if the required amount of roll axis inclination is within the pre-given tolerance range. In this case, the required amount of roll axis inclination is set as the target amount of roll axis inclination, and if it exceeds the upper limit of the allowable range, the upper limit is set as the target amount of roll axis inclination,
If it falls below the lower limit of the allowable range, set the lower limit as the target roll axis inclination, incline the rolling roll axis by this target roll axis inclination amount and start rolling. The load was actually measured, and the required amount of roll inclination of the rolling roll axis to achieve the target taper under the measured rolling load was determined using Formula 6, and the required amount of roll axis inclination was given in advance. If it is within the allowable range, the required roll axis inclination amount is set as the target roll axis inclination amount, if it exceeds the upper limit within the allowable range, the upper limit value is set as the target roll axis inclination amount, and if it is below the lower limit of the allowable range. A rolling method characterized in that the lower limit is set as a target roll axis inclination, and an axially tapered plate is obtained by performing rolling while correcting the inclination of the rolling roll axis so as to match the target roll axis inclination amount.

However, l: Si: Δ51': Pass No.

Average roll gap Right and left roll gap difference (per rolling width) Right and left) Hl: Average plate thickness in the width direction ΔH1: Taper (difference in plate thickness in the width direction) Fl: Sum of rolling loads on the drive and work sides ΔFl: Rolling on the drive and work sides Difference in load MTa%MDa, MTdlMDd: Coefficient (mill constant) B: Distance between roll chocks W: Rolling width ΔD 2. Roll left and right diameter difference (3) In the rolling method described in (1) above, ■Roll axial direction The upper and/or lower rolls with diameter differences in an inclined manner are arranged so that the larger diameter sides face the same side of the rolling mill, and in the finishing pass, the upper and/or lower roll axes are tilted. A rolling method characterized in that a tapered plate in the width direction is obtained by rolling with a gap difference in the axial direction of the rolls.

[For production] Hereinafter, the effects of each of the configurations (1) to (2) of the present invention will be explained.

(2) By giving the entrance taper of the first finishing pass in the final tentering pass, the change in taper ratio in the first finishing pass is minimized and camber and crop piece elongation are prevented.

■In order not to conflict with the roll axis tilt limit on the equipment,
The target taper for each finishing pass is set so that the occurrence of camber is as small as possible within the allowable range, and in detail, the taper ratio [= taper / average plate thickness] as shown in Figure 3 is set to achieve the target taper. To accurately determine the amount of roll axis inclination for

In FIG. 3, the straight line A represents each pass target taper for achieving a constant taper rate, and ΔHmax represents the maximum taper determined from the roll axis inclination limit. The white circles on the compatibility line are the target tapers for each pass when conventional constant taper rate rolling is performed. Further, the triangles on the straight line B are the target tapers of each pass when the taper size is constant. Furthermore, the black circles on the polygonal line C represent each pass target taper determined by the method of the present invention.

(2) Limits the amount of roll axis inclination to within the equipment limits to maintain equipment maintenance.

(2) By automatically controlling the plate thickness and taper simultaneously during rolling, roll axis inclination and inclination prediction errors are canceled out, achieving high plate thickness accuracy.

(2) The difference in diameter of the tapered roll compensates for the tilted side of the roll axis, resulting in a large taper.

(Example) There is a lot of knowledge in the past regarding the rolling of so-called flat plates having the same thickness in the width direction, and it is easy to create a rolling pass schedule for flatly rolling them.In the present invention,
Prior to rolling, a rolling pass schedule is created to flatten a flat plate having a thickness between the maximum thickness and the minimum thickness of the tapered plate in the width direction from a material having a predetermined thickness. As a result, the target sheet thickness on the exit side in each rolling pass is determined.

Next, the target teno\- (width direction sheet thickness difference) in each finishing pass is calculated from the final 1<< to the upstream No<< by using equation (1).

However, i: Finish rolling pass number.

ΔOld: i-pass target taper Hi: i-pass target average plate thickness εt, (nt): Lower limit of allowable range of taper ratio change The allowable range of taper ratio change ε(Hi) is based on the camber that occurs in the rolled material, Refers to the range of taper rate changes on the input and exit sides of the pass that stay within the specified tolerance. Here, ε() If) is a quantity defined by the following equation.

The allowable range of taper ratio change ε varies depending on rolling conditions such as plate thickness and temperature, but it is particularly strongly dependent on plate thickness. FIG. 4 shows the range of ε with respect to the plate thickness H.

In the same figure, the circle mark indicates the actual rolling result when the steel plate temperature is 700℃, the 0 mark indicates the actual rolling result when the steel plate temperature is 900℃, the Δ mark indicates the actual rolling result when the steel plate temperature is 1100℃, and the white mark indicates the actual rolling result when the camber is within the allowable value. , black boxes indicate cases in which camber exceeds the allowable value. From these actual rolling results, if the taper ratio change in each pass is within the shaded area in the figure, the camber will fall within the allowable value. In equation (1), the lower limit value ε of the shaded area ε shown in FIG.

apply. In this case, ε is expressed as a function of the plate thickness Hi, ≦1×εL (old)≦0, that is, 0×1+εL(Hl)≦1 (3). Therefore, by setting the target taper for each pass using equation (1), the constant taper rate (Δ)It-1=ΔH
The taper of the upstream pass can be made smaller than in the case of the case of the umbrella H1-1/Hi), and the rolling camber caused by the roll axis inclination limit, which will be described later, can be made smaller.

In FIG. 3, each pass target taper determined by the above method is indicated by a black circle. For example, the procedure for determining the target taper of the n-4th pass from the target taper of the n-3rd pass (black circle) using the equation (1) will be explained as follows using the figure. First, find the taper of the n-4th pass so that the taper ratio is the same as that of the n-3rd pass (X on Hn-4 in the same figure).
mark). Next, find the lower limit value εL(Hn-4) of the allowable range of taper ratio change corresponding to the plate thickness Hn-4, and multiply the taper indicated by the x mark by (1+ε(Hn-4)). The target taper is n-4 passes (black circles in the figure). By continuously performing this operation starting from the final n-th pass and working towards the finishing first pass, the target taper ΔHi for each pass is
(i-1 to n) are found.

Note that in the area where the plate thickness is thin, the white circle lies on the taper rate - constant straight line A, but in the upstream pass where the plate thickness is thick, the maximum taper Δ
It must be set to Hmax. Therefore, the white circle is straight line A
Each pass that deviates from the camber will result in camber. Further, the triangles on the straight line B are the target tapers for each pass when the taper amount is constant, but in this case, the taper rate changes in all passes, so a large camber occurs. On the other hand, if each pass target taper Δold is determined by the above method, the roll axis inclination of each pass can be kept small.
Moreover, rolling can be performed without causing camber. Also, the polygon line C collides with a certain path and changes the target taper by Δ)
Even if it has to be 1max, the change in taper ratio before and after the pass is much smaller than in the conventional method (white circle and triangle), and the amount of camber generated is extremely small.

The above calculation determines the target taper for each finishing pass.

Furthermore, the amount of taper imparted in the final tentering pass, that is, the initial taper ΔHO in finish rolling is determined by equation (4).

ΔHO=(1+ε(Hi)) Umbrella Δ Hi
Umbrella HO/H1... (4) However, HO: Thickness at the completion of tentering (average thickness) Hl: Average plate thickness on the exit side of the finishing cutting pass ΔH1: Target taper of the first finishing pass As shown in Figure 5 (a) In the final tentering pass, the roll gap is changed during rolling to provide a taper in the rolling direction by ΔHO. After that, the slab 4 is turned 90 degrees and finish rolling is performed as shown in FIG. 5(b). In FIG. 5(b), dl and dl are the distances between the roll axes at the left and right chock positions, The roll axis inclination amount ΔSt is expressed as di-dl. Also, the thickness difference in the width direction (tl-t
2) is the taper ΔHi.

Next, the required roll axis inclination amount Δsi for each finishing pass to achieve the target taper ΔHi is calculated using equations (5) and (6).
Obtained by the formula.

ΔSi = ΔSt' Umbrella B/
W-ΔD... (6) However, ISi ΔSi': ΔSt Pass No.

Average roll gap Left and right roll gap difference (per rolling width) Roll axis inclination (right and left of the distance between the axes of the upper and lower rolls at the chock position) ■ - Average plate thickness in the width direction Δold: Taper (difference in plate thickness in the width direction) Fi : Sum of rolling loads on the drive and work sides ΔFi: Difference in rolling loads on the drive and work sides MTa%MDa, MTd, MDd: Coefficient (Mill constant) B = Distance between roll chocks W: Rolling width ΔD 2 Roll left and right diameter difference here So, Fi and ΔFi are) It-1, Hl, ΔHi-
1. This is a value calculated based on Δold, rolling width, steel plate temperature, etc. MTa corresponds to the mill constant of the general one-dimensional gauge meter formula, which is a coefficient representing the influence of the sum of rolling loads on the average plate thickness. Hereinafter, MDa is a coefficient representing the effect of the rolling load difference on the average plate thickness, MTd is a coefficient representing the effect of the rolling load sum on the taper, and MDd is a coefficient representing the effect of the rolling load difference on the taper, all of which are values specific to the rolling mill. It can be considered as Mill's constant in a broad sense.

Furthermore, when using upper and/or lower rolls having diameter differences inclined in the roll axis direction, they are arranged so that the larger diameter sides face the same side of the rolling mill. Figure 6 (a) shows a case where the upper and lower rolls have a diameter difference, Figure 6 (b) shows a case where only the upper roll has a diameter difference, and Figure 6 (c) shows a case where only the bottom roll has a diameter difference. Indicates the role arrangement when Of course, the same figure (d)
As shown in the figure, it is also possible to use normal rolls with no difference in diameter between the top and bottom.

ΔD in equation (6) is defined as the total value of the difference in left and right diameters of the upper and lower rolls.

By setting the necessary roll axis inclination determined by the above procedure and performing finish rolling, it is possible to produce a steel plate having the desired widthwise taper and no or very small camber.

On the other hand, during actual rolling, the following two items should be further considered.

(1) The limit of the amount of roll axis inclination determined by the structure of the rolling mill. (2) Errors in average plate thickness and taper caused by prediction errors of rolling loads (sum, difference). The limit of the amount of roll axis inclination varies depending on the specifications of the rolling mill. Although it is different, in general thick plate finishing mills, the total of upper and lower rolls is ±1
It is about 0 to 30 mm. The absolute value ΔSc of this limit is the sum of the upper roll inclination limit absolute value ΔScu and the lower roll inclination limit absolute value ΔScl.

From the target roll axis inclination amount ΔSf and ΔSc obtained by equation (6), the target roll axis inclination amount ΔSat for each pass is determined by the following equation.

ΔSai = Min(lΔSil, ΔSc) * sg
n(ΔSi)...(7) However, sgn(ΔSt) represents the sign of ΔSt. Here, if 1ΔSil>ΔScu, lΔ5ail=ΔS
c, the required roll axis inclination amount cannot be set, and the target taper ΔHi cannot be achieved. Therefore, before and after the pass, the taper ratio changes beyond the allowable range for camber generation, and camber occurs. However, in the present invention, as shown in equations (1) and (3), the target taper itself of each pass is set as small as possible,
The necessary roll axis inclination amount ΔSt is also considerably smaller in absolute value than in the case of full taper ratio rolling. Therefore, ΔS
There are very few cases where t deviates from the slope limit ΔSc, and even if it deviates, the amount is small and no large camber occurs.

Note that the target axial inclination amount ΔSu of the upper roll and the target axial inclination amount ΔSX of the lower roll can be arbitrarily determined within a range that satisfies the following formula.

ΔSu+ΔSX=ΔSat and 1ΔSul≦Sc and 1
Δ5j2 l≦Δ5cj2 ”・(8) From the average roll gap St and the target roll axis inclination amount ΔSal, calculate and set the roll gaps Sdi and Swi at the left and right chock positions using the following formulas, and perform rolling. .

The average plate thickness and taper errors are compensated by feedback AGC shown in FIG. Note that the left side of the rolling roll in the figure corresponds to the work side (WS), and the right side corresponds to the drive side (05).

The left and right rolling loads measured by the rolling load meter 6 during rolling are first added to the rolling load sum FT by the adder Al, and then added to the rolling load sum FT by the adder A2.
It is converted into a rolling load difference Fd. Bl.

B2 is a target rolling load sum FTO and a target rolling load difference FdO, respectively, which are given by the rolling process computer 11. Adders A3 and A4 calculate the differences FT-FTQ and Fd-FdO between the actual measurement value and the target value. 83~B
6 are mill constants in a broad sense, and these are also given by the rolling process computer 11. The above FT-FTO,
Fd-FdQ is converted into left and right hydraulic cylinder position correction values, that is, left and right roll gap correction values ΔSb and ΔSw, via B3 to B6 and adders A5 and 86. Furthermore, this value and the roll gap target value Sb, , Swo and the measured roll gap value sb%Sw from the hydraulic cylinder position detector 9
The position feedback signals are added by adders ^7 and 88, and multiplied by feedback gain C, which is output to the servo valve 8 as a final left and right roll gap correction command value, and the hydraulic sill position is corrected.

According to this control, the average plate thickness Hai and taper ΔHat that are actually obtained are as shown in the following equations.

...(11) Fat: Actual rolling load sum ΔFat: Actual rolling load difference C: Feedback gain From equations (5) and (11), the error from the target value of actual plate thickness and taper is as follows. The formula becomes

As can be seen from equation (12), if C=t, the error is 0.
As a result, the target average plate thickness and taper can be obtained.

Generally, to stabilize the control system, C = O, a ~ 0.9, but even in that case, if the above control is not performed (C -
Compared to O), the error in plate thickness and taper is 175 to l/10.
can be reduced to

Although FIG. 7 shows the case where the lower roll has the AGC mechanism, the control method when the upper roll has the AGC mechanism is also exactly the same as the above method.

The results of rolling using the method of the present invention are shown below. Table 1
shows the combination of rolls used for rolling. Case A is when there is no diameter difference between the upper and lower rolls, and case B is when only the upper roll is 5.
Case C is a case where the upper and lower rolls have a diameter difference of 5 mm each. A combination in which a diameter difference is provided only to the lower roll is also considered, but this can actually be considered to be the same condition as case B.

The roll body length of the rolling mill used in this example was 550 mm.
0mm, the distance between the left and right chocks is 6980mm, and the roll axis inclination limit on the equipment is 10mm in total for the upper and lower rolls.

Table 1 Joule. Note that the work side of the rolling mill was set to be the thicker side. The sign of the roll axis inclination amount is positive when the distance between the roll axes on the work side of the rolling mill is widened.

Table 3(a) Table 2 shows the rolling conditions.

Table 2 Table 3 shows the rolling pass schedule calculated according to the method of the present invention. Table 3(a) is the pass squeever amount for case A, Table 3(b) is for case 81, and Table 3(C) is for case C.

Table 3(b) Table 4 shows the results of rolling according to the pass schedule in Table 3. Table 4 (a) is case A1 Table 4 (b) is case 8
1 Table 4 (C) is the result of case C.

Table 4(a) Table 3(C) Table 4(b) Table 4(C) Note that tapered rolls are used in Case B and Case C, and the difference in diameter is 0.00% of the average diameter (approximately 1190 mm). The values were as small as 4% (Case B) and 0.8% (Case C), and no meandering or camber of the rolled material due to the difference in left and right circumferential speeds was observed.

〔Effect of the invention〕

As shown above, according to the method of the present invention, it is possible to manufacture a widthwise tapered plate with excellent plate thickness accuracy and less camber.

[Brief explanation of drawings]

Figure 1 is a diagram showing an example of a metal plate product with variable thickness.
) shows a plate with a different thickness, (b) shows a tapered plate, and (C) shows a tapered plate in the width direction. Figure 2 shows the relationship between taper ratio change, crop, and camber. (al) shows the state of rolling when the plate thickness is thick, viewed from the steel plate advancing direction, (al) shows the view from above the rolling mill, and (bl) and (bl) show the rolling process when the plate thickness is thin. Figure 3 shows the relationship between the outlet side plate thickness and target taper for each pass, the horizontal axis shows the outlet average plate thickness, the vertical axis shows the outlet taper, and Figure 4 shows the allowable taper rate range. In this figure, the horizontal axis shows the average plate thickness on the outlet side, and the vertical axis shows the rate of change in the taper ratio. Figure 5 shows the rolling method of the widthwise tapered plate, and Figure 5 (a) shows the initial taper imparting. Fig. 6(b) shows the finishing pass rolling method, Fig. 6 shows the arrangement of work rolls, and Fig. 6(a) shows the method when the upper and lower rolls have a diameter difference. If only the upper roll has a diameter difference,
In the same figure (c), when only the lower roll has a diameter difference, the intermediate part (d
) indicates the case where there is no diameter difference between the upper and lower rolls, and the 7th
The figure shows an automatic control circuit for average plate thickness and taper. 1... Steel plate product, 1a... Steel plate entry side shape, 1b...
・Steel plate exit shape, 2u... Upper work roll, 22...
・Lower work roll, 3u・°・Upper early up roll, 3k...lower back up roll, 4...slab,
5...Rolling mill housing, 6...Rolling load meter, 7.
... Hydraulic cylinder, 8... Servo valve, 9... Hydraulic cylinder position detector, 10... AGC controller, 11... Rolling process computer. (Q) Agent Patent attorney Masamitsu Akizawa and one other person π1 Figure 2u (θI) (bt) Figure 4 (Ha) Figure 3 (Q) I Cb) π5 Figure

Claims (3)

[Claims] (1) [1] When rolling a material with a predetermined thickness to produce a steel plate with different thicknesses in the width direction, taper rolling is performed in the tentering rolling direction in the final tentering pass to reduce the initial taper (difference in thickness in the width direction). [2] In the subsequent finish rolling,
The change in taper ratio (taper/width direction average plate thickness) on the inlet and outlet sides of each pass is within the taper rate change tolerance range, which is wide in thicker plate areas and narrower in thinner plate thickness areas. , and determine the target taper of each pass so that the inlet taper of each pass is at the lower limit of the allowable taper range determined from the outlet taper and the allowable taper rate change range, or a value close to the lower limit, and Required slope amount ΔS of the roll axis of the rolling roll in each pass to achieve the target taper
i is determined by solving the gauge meter equation regarding the average plate thickness and taper defined by the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. If it is within the range, the required roll axis inclination amount is set as the target roll axis inclination amount, if it exceeds the upper limit of the allowable range, the upper limit value is set as the target roll axis inclination amount, and if it is below the lower limit of the allowable range, the required roll axis inclination amount is set as the target roll axis inclination amount. A rolling method characterized in that a tapered plate in the width direction is obtained by rolling with a lower limit value as a target roll axis inclination. However, i: Pass No. Si: Average roll gap ΔSi′: Left and right roll gap difference (per rolling width) ΔSi: Roll axis inclination amount (left and right difference in distance between the axes of the upper and lower rolls at the chock position) Hi: Average plate thickness in the width direction ΔHi: Taper (width) Fi: Sum of rolling loads on the drive and work sides ΔFi: Difference in rolling loads on the drive and work sides MTa, MDa, MTd, MDd: Coefficient (Mill constant) B
: Distance between roll chocks W: Rolling width ΔD: Roll left and right diameter difference (2) [1] When manufacturing steel plates with different thicknesses in the width direction by rolling a material with a predetermined thickness, taper rolling is performed in the tentering rolling direction in the final tentering pass to reduce the initial taper (difference in thickness in the width direction). [2] In the subsequent finish rolling,
The change in taper ratio (taper/width direction average plate thickness) on the inlet and outlet sides of each pass is within the taper rate change tolerance range, which is wide in thicker plate areas and narrower in thinner plate thickness areas. , and determine the target taper of each pass so that the inlet taper of each pass is at the lower limit of the allowable taper range determined from the outlet taper and the allowable taper rate change range, or a value close to the lower limit, and The required amount of inclination of the rolling roll axis for each pass to achieve the target taper is determined by solving the average plate thickness defined by the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and the gauge meter formula regarding taper. [3] If the required amount of roll axis inclination is within a predetermined tolerance, the required amount of roll axis inclination is set as the target roll axis inclination, and if it exceeds the upper limit of the allowable range, the upper limit is set as the target roll. If it falls below the lower limit of the allowable range, set the lower limit as the target roll axis inclination, incline the roll axis by this target roll axis inclination and start rolling, [4] During rolling. The rolling load was actually measured by load cells on the left and right sides of the rolling mill, and the required roll inclination amount of the rolling roll axis to achieve the target taper under the measured rolling load was calculated using the formula ΔSi=ΔSi'*B/W-ΔD. If the required amount of roll axis inclination is within a predetermined tolerance range, the required amount of roll axis inclination is set as the target roll axis inclination amount, and if it exceeds the upper limit value within the allowable range, the upper limit value is set as the target roll axis inclination amount. If the roll axis inclination is below the lower limit of the allowable range, the lower limit is set as the target roll axis inclination, and rolling is performed while correcting the inclination of the rolling roll axis to match this target roll axis inclination. A rolling method characterized by obtaining a tapered plate in the width direction. However, i: Pass No. Si: Average roll gap ΔSi′: Left and right roll gap difference (per rolling width) ΔSi: Roll axis inclination amount (left and right difference in distance between the axes of the upper and lower rolls at the chock position) Hi: Average plate thickness in the width direction ΔHi: Taper (width) Fi: Sum of rolling loads on the drive and work sides ΔFi: Difference in rolling loads on the drive and work sides MTa, MDa, MTd, MDd: Coefficient (Mill constant) B
: Distance between roll chocks W: Rolling width ΔD: Roll left and right diameter difference (3) In the rolling method according to claim 1, [5] the upper and/or lower rolls having diameter differences inclined in the roll axis direction are arranged so that the larger diameter sides face the same side of the rolling mill; A rolling method characterized in that, in the finishing pass, a widthwise tapered plate is obtained by rolling with the upper and/or lower roll axes tilted to provide a difference in gap in the roll axis direction.