JPS6182913A - Method for computing torque-arm in hot continuous rolling - Google Patents

Abstract

PURPOSE:To obtain an excellent tension control and to improve the quality of a steel stock rolling, by correcting a torque arm in consideration of the influence of the temperature difference between the front and rear ends of a steel stock. CONSTITUTION:Respective differences DELTAl3, DELTAl2, DELTAl1 between respective torque arms ls3, ls2, ls1 of stands 3, 2, 1 obtained from rolling loads and torques at the time when the front end of a steel stock is bitten, and respective torque arms le3, le2, le1 obtained at the time when the rear end of stock runs out of rolls, are assumed that said differences depend on the temperature difference between the front and rear ends of stock. And the torque arm used for computing the tension of stock at the next pass is corrected in consideration of said temperature difference. In this correction, a linear or curvilinear interpolation, etc. is used for the difference.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for calculating a torque arm in continuous hot rolling.

(Conventional technology) Tension (including compressive force) generated between stands during continuous rolling
must be reduced as much as possible.

For this reason, it is common practice to detect the tension between the stands and perform feedback control, but in cases where a general tension detector cannot be used, such as when rolling shaped steel, special measures are taken to detect the tension.

That is, in continuous rolling, the relationship between the tension between stands, rolling load, and rolling torque is as follows: G = 2 gP + R (Tb - Tf)
・・・・−(11G: Rolling torque, e: Torque arm, P: Rolling load, R: Roll radius, Tb: Back tension, T
f: A relational expression for front tension is established, and the tension is calculated using this expression.

The rolling load and torque in the absence of tension when the copper material is caught in the most upstream rolling stand are detected, and the torque arm of the most upstream rolling stand is determined from these detected values.

Based on this torque arm, changes in the rolling torque and rolling load of the most upstream rolling stand when the :1III material is bitten into the next stage rolling stand are calculated as the inter-stand tension. The torque arm of this next-stage rolling stand is determined from this inter-stand tension, rolling load and torque at the next-stage rolling stand. Hereafter, as the downstream stands of the steel material are involved, the torque arms of the downstream stands are determined one after another, the torque arms of the stands of the next stage, and so on.

(Problems to be solved by the invention) In the conventional method, the torque arm is calculated from the 61f weight and torque when the steel is bitten into the rolling stand.In the case of hot rolling, the tip of the steel It is said that the temperature difference between 41)' and the rear end is ~70°C, and calculating tension using the open torque arm value during this period would result in an error equivalent to H, l. This will inevitably have a negative impact on steel rolling.

(Means for Solving the Problem) The present invention corrects the torque arm by taking into consideration the influence of the temperature difference between the leading and trailing ends of the steel material. That is, the torque arm obtained when the leading end of the hot material is bitten into the rolling stand and the torque arm obtained when the trailing end of the steel material passes through the rolling stand are used. Compare these two types of torque arm values, and if there is a difference between these values, it is assumed that the difference is due to a temperature difference between the steel materials, and the torque arm used for tension calculation in the next pass is corrected according to the temperature difference. . Correction methods include linear interpolation of this difference, curve interpolation, or, if the tiA degree distribution from the tip to the rear end of the steel material is measured, a table is used for interpolation.

FIG. 1 shows an example of the final four stands. Below, we will use this to calculate the torque arm when the steel material is biting,
Calculation of the torque arm when the vehicle breaks through and how these two types of torque arm values are corrected based on the temperature difference between the front and rear ends of the steel material will be explained.

The method of detecting the load and torque at the time of biting and calculating the torque arm will be explained. Equation (1) above holds true between the inter-stand tension, rolling load, and rolling torque, but this can be expressed as 4
If you apply it to the stands, add subscripts that correspond to each stand, and modify the script, G3 = 21: + P3
+ R3(T:14-Tza) --------(
2) G2 = 2gz P2 +R2 (T23-T12
) −−・−・= −−(3) G+ = 211X
l+ P+ + RIT+2 ・-・・・・・
・ ・ ... (4) G: Rolling torque, P: Rolling load,
T: Tension, e: Torque arm, R: Roll semi-closed.

The torque arm of each stand is calculated by setting the tension between the 4 stands of the immediately upstream stand to zero, and the steel Koshirae 3 stand and the Hayabusa 2 stand are not wedged and the tension T23 is not present. According to equation (2), torque arm +3 is 2111!3=[stone 13 − ・ −・ ・・ (
5) When the torque arm is inserted into the next 2nd stand, the torque arm is determined from equations (2) and (3) using eJ.
+2 is 2e・= shout 1゜Togiri [tan 12 ([egg 2-2e・)
・・・・・・・・・・・・(6) Similarly, when it is inserted into the ≠3 stand, using torque arms +3 and +2, (
From formulas 2), (3), and (4), torque arm el is +
...(7) can be calculated respectively. In addition, i=3 of Ol
．． 2 and 1 indicate the detected values when biting into each stand of +3, ≠2, and +1, respectively.

Once the torque arm is determined, the tension between the stands is (2), (
3) and (4), using R3, +2, and el as parameters, T34=ω+2P3 ShinjuT 23. ,, ,,
, , , , , , , , , -1-- , = -, =
(8) G2 (Jz T23 = 7; +2P2T27+TI2...
・・・・・・・・・・・・・・・(9) T12 =”−
＋ 2P+ i ・・・ ・・・・・・・・・・・・
......(10) It can be expressed as RI Rl. That is, torque arm e3, +
2. If eI is known, (8), (9), (10)
The tension between the stands can be calculated from each formula.

Next, we will explain how to calculate the Torufirm when passing through a steel stand. Tension between stands, rolling load i1j
The equations (2), (3), and (4) above are established between the rolling torque and the rolling torque. The torque arm is determined from the torque, and when two stands are removed and one stand is set without tension TI2, from equation (4), the torque arm e1 is 2e+ = 1 j1...・・・・・・−
・・・・・・・・・・・・・・・・・・・・・(11)
Also, remove the crocodile 3 stand by using the torque arm el while the crocodile is on the stand (3), (4
) From each equation, torque arm e2 passes through the purple 4 stand ≠ 3, sum, kai 1 stand [two forces], and using torque arm elX (12), (
From each formula (2), (3), and (4), the torque arms e and 3 can be calculated as follows. In addition, i of Oi = 1.2
．． 3 indicates stored data that passed through each stand of $2, 1, #, and 4, respectively.

In this way, when steel stands are penetrated, the GlP of the time is memorized, and after passing through all the stands, the above (11) and (1)
2) Calculate the torque arms lx, 12, and I3 of each stand with flower 1, ≠ 2, and 3 based on the equations (13). Note that this torque arm will be used to calculate the tension of the steel material for the next bus, and the tension calculation formula was obtained previously (8) and (9).
, (10) are used.

In this invention, (5), (
6) The values shown by the formulas in (7) are 2, and the torque arm of each stand in Reference 1 and the cutout of the rear end of the steel material are calculated as follows:
13), (12), and (11) are 3, Hana 2,
1. The difference between each stand torque arm is estimated to be the effect of the temperature difference between the front and rear ends of the steel material, and the torque arm used for calculating the tension of the next bus steel material is corrected in consideration of the temperature difference, It is.

(Function) As a correction method, there are many methods such as the linear interpolation and curve interpolation mentioned above, but here, a method using linear interpolation will be explained as an example.

In other words, the rolling time for 1 M44 from stand #3 to stand L is the difference in the torque arm calculated on the A1 previous bus, and 8e1 is the rolling time, and the elapsed time from the time when the steel material is placed on the ≠3 stand is t % (5 ), (6), and (7), each stand torque arm obtained when the tip of the steel material is bitten is
If h11 front torque arm ei is 1i = 4h
i100− t −t< −−−−=・=−−=−・−
(14) i = 3.2.1, K: can be expressed as hlt positive coefficient.

This equation (14) is shown in the graph block diagram in Figure 1, but
For Shiri-Nuki, the torque arm obtained from Time Record 1 is dpi (i = 1s2.3), and △41 is (5ci -
ekl).

(Effect of the invention) In this way, the temperature-compensated torque arm e3, (12
, Qs is used to calculate the tension of the copper material in the next pass as described in (8), (
9) and (10) are carried out based on each formula, which allows for more accurate tension calculation and better tension control, which greatly contributes to improving the quality of rolling of 1-ru material.

[Brief explanation of drawings]

Figure 1 is a sequence/block diagram for calculating, comparing, and correcting the torque arm when the steel material is caught in the rolling stand and when it is punched out.

Claims (1)

[Claims] 1. G=2lP+R(Tb-Tf) established between rolling torque, rolling load, and tension, G: rolling torque, l: torque arm, P: rolling load, R
: Roll radius Tb: rear tension, Tf: front tension Calculate/control tension using the relational expression. In tension control of a continuous rolling mill, the torque arm is calculated from the load and torque when the tip of the steel material is bitten by the rolling stand. The load and torque when the rear end of the steel material passes through the rolling stand are memorized, and the torque arm calculated when the rear end of the steel material passes through the final rolling stand is compared. A method for calculating a torque arm in continuous hot rolling, characterized in that the torque arm is estimated to be due to a difference in end temperature, and the calculation of the torque arm in the next pass steel rolling is corrected based on the temperature difference.