FI93805C - Method for controlling a continuous roll line with multiple roll chairs - Google Patents

Abstract

The invention relates to a control device for a continuous multistand rolling mill, in particular a light section mill, which has a computer with a memory for rolling program-specific variables, e.g. rotational speed set point values, armature currents and exit cross-sections and for the calculation of derived variables, e.g. the rolling stock tensions between the stands, minimum tension control being performed by controlling the rotational speeds of the individual stands (1m;1n) of the mill via additional rotational-speed set point values, these values being formed in accordance with a predetermined computing rule taking into account stored empirical values (KE) and the additional rotational-speed set point values being formed in accordance with the following computing rule: <IMAGE>

Description

93805

A method for controlling a continuous rolling line comprising several rolling chairs

The invention relates to a method for controlling a continuous rolling line comprising several roller chairs, preferably a reinforcing steel line, whereby, according to the anchor currents (Jäi, Jä2) of the individual roller stands (m; n), 10 (m +) are formed before and after the entry of the rollable area; n + l) according to a predetermined calculation rule, additional target values for the speeds (n £%) and where the speeds of the individual roller chairs are controlled by additional target values of the speeds with the aim of adjusting the minimum tensile.

Such a method is known from AEG-Mitteilungen, 56 (1966) Nr. 1, pages 54 to 57 and from Technische Mitteilungen AEG-TELFUNKEN, 66 (1976) Nr. 6, pages 255-261. However, the methods disclosed in the publications do not allow drawing in which the rolling material is not subjected to compressive forces.

DE-2 800 197 A1 discloses a method and arrangement for adjusting the tensile stresses of a rolling material between the rolling mills of a double rolling bus. However, the control method described is too complicated in certain application cases, in particular when rolling profiles or bars. This applies in particular to the modernization of existing, relatively slow-moving rolling mills.

The method according to the invention, which is particularly suitable for a bar blade rolling line, is characterized in that .. additional target values (%%) for speeds are further developed according to the tensile current target value (AJ *), which tensile current target value is defined experimentally as a specific target tension (6 * z) in the rolling material. Preferred embodiments of the invention are set out in the appended claims 2-6.

2 93805

Due to the target drawing used in the method according to the invention, compressive forces on the rolling material are avoided.

Other advantages and details will become apparent from the following description of working examples in connection with the drawing. The drawing illustrates: Fig. 1 a schematic representation of a rolling path comprising a roller chair as control of rolling material speeds, Fig. 2 a schematic representation of a rolling path comprising lower rolling material speeds, Fig. 3 a schematic representation of a control device according to the invention.

In Figure 1, individual roller chairs are indicated by the number 1 and a footnote. The rolling stock passes through a symbolically illustrated in the direction of the arrow. The adjustment of the minimum tension implemented by means of the control device 2 is described in this example between the roller chairs 1B and 1B + 1. At the roller chair 1B, the anchor current JA1 and JM is measured and transmitted via the signal path 12 to the control device 2. The control device 2 determines an additional target speed value n £% and transmits it via the signal path 13 to the roller chair 1B + is divided on the one hand into a compaction time tA1 25 for adjusting the passage of the roller chair 1B, and on the other hand into a safety time ts1, whereby after the compaction time tA1, a change in the target value for the next roller chair lmtl is determined. The direction of adjustment is given by the dashed line 14, but it can also be in the direction of the dashed line 14 ', i.e. in the opposite direction.

The adjustment of the individual rolling mills takes place at high rolling material speeds, for example with the main rolling material pass times of 1-2 seconds from one rolling mill to another in each case, so that the additional target speed value is changed only with the next rolling material passage. The adjustment phase thus extends from rod to rod.

3 93805

In Fig. 2, where the roller chairs are marked with ln, the arrangement and operation of the control device 2 is basically similar to Fig. 1, but in it the effect of the next roller chair ln + 1 already takes place during the pick-up of the same rolling material. Due to the lower rolling material speed, the compaction time tA1 then first adjusts the initial passage of the rolling mill ln, the value of the current JA2 is stored in the control device 2n.j and the adjustment is carried out. The new load current thus generated is adjusted by the compaction time tB1, and the current 10 AND1 for the calculations of the minimum traction control 2n is stored. A safety time tsl has also been designed for this, which avoids duplication of time.

In Fig. 3, the number 2 also denotes a control device according to the invention, the computer part 2 'of which contains 15 roll material flow imitation models. In addition, the control device 2 comprises a target value control section 2 '', in which a speed target value n * is formed, the signal of which is denoted by 11. 2 '' 'describes a variable input unit of the control device 2 to which signals from the keyboard or monitor are provided via signal path 8 t · · The current position of the rolling material is fed to the imitation of the rolling material path via the signal path 9. Thus, the computer 2 can preferably supply the anchor currents JA1, JA2 fed through the six-pole Butterworth filter 10 to the traction-free and traction-exposed space, divided locally into memories 3 and 4.

From the memories 3 and 4, the signals of the anchor currents JA1, JA2 are fed to the separation device 5 for the draft-free and tensile-exposed state, which is also given the target value AJa of the tensile-30 current, an experimental value dependent on the speed and rolling program, variable feed 2 '' ' . In the unit 5, on the basis of this information, the traction current error is determined, which together with the experimental value KE is fed to the multiplier 6, in which the target value of n-% of the round-35 number is formed. The transfer unit, which takes care that the signal is generated depending on the speed in the slit of the rolling material or at the moving bar corresponding to Fig. 2 as a control command via the target value set 2 '' to the target value n *, is denoted by 7. The units 5 3, 4, 5, 6 and 7 together form for continuously determining and timely transmitting the target value n * of the speed of the counter part of the control device.

The tensile current target value AJa, which depends on the specific target force 6 ^ of the Vals dry matter, is calculated from the equation. δΜ · AA * dw * n * · AJa = - 2 · i · P „· 9555, 15 where AÄ is the output cross-section (mm2), d ^ is the diameter of the roll (mm), n * is the instantaneous speed target (Upm), J, ^ the rated anchor current of the motor (A), i gear shift and PH the rated motor power (KW).

Claims (7)

A method for controlling a continuous roll line with multiple roll chairs (1), preferably a closing line, in accordance with anchor currents (JA1, J, ^) for roll motors for individual roll chairs (m; n). that the roll material inserted into the subsequent individual roll chair (m + 1; n + 1) generates additional setpoints (n £%) for rpm according to a predetermined calculation rule and where the rpm of the individual rolled chairs is controlled by means of additional setpoints for rpm. a minimum drag control as milling, characterized in that the additional setpoint values (n £%) for the revolutions are further developed in accordance with a draw current setpoint (AJX), which is determined experimentally as a specific set point (6) in the roll material. 2. A method according to claim 1, characterized in that the additional setpoint values (¾%) for the speeds are generated according to the counting rule • · <'20 nZ% "* (Ye ~ * ^ A2" AJÄ), wherein KE is an experimental value stored in a memory. 3. A method according to claim 2, characterized in that the experimental value KE is formed in the form of a percentage change in speed per N / mm2. Method according to claim 2 or 3, characterized in that the experimental value KE is determined by the control movements exceeding the limit values. 5. A method according to any of the preceding claims, characterized in that the draw current setpoint (AJX) is derived from a predetermined specific draw 6 according to equation 8 93805, 6m * Aa. d · · n *. JM 5 AJa = - 2. i ♦ PH. 9555, where AÄ is the output cross-section of the drum material in the unit mm2, d „is the drum diameter in the unit mm, n * is the setpoint of 10 rpm in the unit rpm, is the anchor current of the drum motor in unit A, i is the gear transmission and PH is the motor nominal power in unit kW. Method according to any of the preceding claims, characterized in that the draw current setpoint (AJa) is determined in several unregulated passages on the basis of instantaneous value tolerances for the draw in several unregulated passages. «