DE2337830A1 - ARRANGEMENT FOR TENSION- AND PUSH-FREE ROLLING OF ROLLED MATERIAL IN A MULTI-STANDED ROLLING MILL - Google Patents

Description

WESTINGHOUSE Erlangen, July 24th, 73

Electric Corporation ™ ". _. Pittsburgh Pa. USA Werner-von-Siemens-Strasse 50

Hein sign: VPA 72/8355 Hk / Tue

Arrangement for tensile and thrust-free rolling of rolling stock in a multi-stand rolling mill

Priority is given to U.S. patent application serial no. 276 of July 31, 1972.

The invention relates to an arrangement for tensile and thrust-free Rolling of rolling stock in a multi-stand rolling train with speed-controlled individual drives, the speeds of which can be preset and in a fixed relationship to one another to avoid looping between the scaffolding stand with one that detects the armature current per scaffold drive and storing device from which the stored value is retrieved and compared with the actual value, if the rolling stock has entered the next stand, with the difference between the stored value and the actual value of the armature current to the speed controller of the drive for the following The framework is supplied as a correction value.

Such an arrangement is known from DAS 1 201 46S. In this known arrangement, the time at which the armature current is stored and the correction value τ «η is interrogated is similar, which is arranged on both sides of the scaffolding, for example an anomaly with light barriers. The distances mix the asvtofisckalt ^ rn \ md the scaffolding so SU WtLlen that in "the" measurement seupuiikteH the 2ir.?3ivj?ingrvoi . C.

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According to the invention, these difficulties are circumvented in that a load sensor is assigned to each scaffold, that the armature current measuring device via a switching element, which is closed depending on the load sensor and as a function of a device which determines the time required for the transport of the rolled material between two adjacent stands, with which the anchor trom is opened storing device is connected and that the output of a comparator forming the difference between the stored and the measured armature current to the speed setpoint generator for driving the following frame via a Switching element is connected, which is closed depending on the load sensor assigned to the following structure.

The invention is explained in more detail below using an exemplary embodiment shown in the drawing. Show it

Figure 1 is a block diagram of the arrangement, FIG. 2 shows the course of the armature current in the case of an impact on the rolling stock

tensile stress exerted, FIG. 3 shows the course of the armature currents in the case of an impact on the rolling stock exerted thrust.

The control device is based on the example of a block or Billet road shown. Usually includes such Roll drawing roughing stands, intermediate stands and finishing stands. The rough rolling mill consists, for example, of six stands, the intermediate rolling mill with tier stands and the finishing mill for example, outer & a scaffolding. For the sake of simplicity, are FIG. 1 only shows scaffolding 1 and 2, although off the BeeeferfifcuBg fcerrorgeht that the establishment if necessary can easily be extended to all G- «calls.

The Wftli5g »rfiste 1 ij» ä 2 «s limits j» Bin Τ * 1ιβη $ £ .ο "14, 16 ,. Dl * üfctr gear 18 bsx * 20 * λ £ I # 3c-fcrcE & l *:? T <is 22 «mostly 24

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(Usually DC shunt motors) are coupled. The motors 22 and 24 of the two roll stands are connected to a busbar 26.

The field winding 28 of the motor 22 is connected to an excitation and speed control device 30. The corresponding Parts for the motor 24 are designated by 32 and 34, respectively. A tachometer generator 38 is coupled to the shaft of the motor 24. The armature currents of the motors 22 and 24 are tapped at resistors 40 and 42 and fed to amplifiers 44 and 46, respectively. A load sensing device 48 is used for the roll stand 1 and, in an analogous manner, a load sensing device is used for the roll stand 2 50 provided.

The load sensing device 48 comprises the tachometer generator 36, a summing amplifier 52, a capacitor 54 and a relay LD 1 with a normally open switch LD 1.1. The load sensing device 50 comprises the tachometer generator 36, a summing amplifier 56, a capacitor 58 and a relay LD 2 with the switches LD 2.1 and LD 2.2. To set the speeds for the stands 1 and 2, setpoint generators 60 and 62 are provided. The setpoint generator 60 contains an amplifier 64 which drives a motor 66 which in turn drives the sliding contact of a potentiometer 68, which is connected to a voltage source and to earth. A preset voltage can be applied to an input of the setpoint generator set by hand. This default voltage determines the beginning of the division of the sliding contact of the potentiometer 68.

The setpoint generator 62 corresponds to the device 60 and contains an amplifier 70 and a potentiometer driven by a motor 72. The only difference between the two setpoint generators is that the amplifier 70 has an additional input which is connected to the switch LD 2.2. In this respect, the equipment of all other roll stands that may be provided corresponds to the equipment of the Roll stand 2.

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A memory circuit M1 is assigned to the roll stand 1. In the same way, a memory circuit M2 is also assigned to the frame 2, but for the sake of simplicity is not shown. The memory circuit consists of an amplifier 78, the output of which is via a relay switch CR 1.1 is connected to an operational amplifier 80 connected as an integrator. The operational amplifier 80 includes resistor 82 and capacitor 86 in the return. The output of operational amplifier 80 is fed back to the input of the amplifier 78 and also connected to a summing amplifier 88 assigned to the frame 2.

The rolling stand 1 is also assigned a device T1 which determines the transport time of the rolling stock and which is used as a Integrator operated operational amplifier 92 with an input resistor 96 and a capacitor 100 in its feedback loop, and an amplifier 102 which receives an input appropriately from the operational amplifier 92 during the other input is connected to the sliding contact of a potentiometer 104, which is connected to the negative pole of a voltage source and to Brde.

The operator gives to initiate the operation of the roller train from the control cabin, the speed to be expected for each scaffold during operation without load accordingly the respective rolling conditions. The rolling motors are then activated by lowering the busbar voltage by 25 # the nominal voltage delayed. This percentage is higher when the transport time of the rolling stock is so great that the Control device can be geeeezt in about 1 1/2 to 2 seconds in action.

The operator then selects the device for automatic speed correction, for example with a push button at. Then a block or billet runs from the furnace into the

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Roll stand 1 a. The armature current of the motor 22 flows through the shunt 40 and to the amplifier 44. The output current I ... of the amplifier 44 corresponding to the armature current is the Summing amplifier 52, the amplifier 78 and the summing amplifier 88 supplied.

The output of the tachometer generator 36 is through a capacitor 54 to the second input of the amplifier 52 and also to the device T1 taking into account the transport time a switch STD 1.1 of a relay STD 1 is connected.

The load sensor 48 determines when the rolling stock in stand 1 is. During acceleration or deceleration, a voltage arises at the capacitive input of amplifier 52, which is equal and opposite to the voltage at the other input of the amplifier, and the relay LD 1 remains in the Rest position. The load torque required for rolling the rolling stock causes the armature current I.- to increase. of the motor, so that an imbalance arises at the output of the amplifier 52 and the relay LD 1 is actuated as a result.

By closing the normally open switch LD, the circuit for the two relays CR 1 and STD 1 is closed. The relay switches CR 1.1 and STD 1.1 close at the same time and thereby actuate the memory 80 and the amplifier 92 which takes account of the transport time.

The amplifier 92 interrupts its operation shortly before the rolling stock enters the roll stand 2. The memory 80 then stores a voltage which is a function of the armature current Ia-i-, which in turn depends on the actual Load torque depends.

_{The input signal 1 ^ 1 is} fed to the amplifier 78 of the memory circuit M1. The output signal of the amplifier 78 is passed to the integrator 80 via the switch CR 1.1, which is now closed. The amplifier 80 works as a reverse

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amplifier, so that the output signal I ,. negative iat. The current I » _{1m is} fed back to the input of the generator 78 via the feedback. Due to the opposite polarity of the signals as? The amplifier's input continues to deliver an output signal until the input signals are equal, ie I .. = I.-

When the switch CR 1.1 opens again, the integrator stores the current I * _{1m corresponding to the load required for rolling due to the charged capacitor 86}

The voltage changes are integrated by the integrator 92, so that at the input of the comparator 102 a voltage is being built. The second input of the comparator 102 is connected to the potentiometer 104- which is set to a negative, the transport time of the rolling stock from the stand 1 to the stand the value to be taken into account is set. If the positive potential corresponds to the negative potential set on potentiometer 104 Equals potential, the relay TD 1 is energized and the normally closed switch TD 1.1 is opened. As a result, the relay CR 1 drops out and its switch becomes CR 1.1 opened.

The variable I ^ is fed to the amplifier 88. When the rolling stock has entered the roll stand 2, the switch LD 2.2 is closed by actuation of the relay LD 2 as a function of the load sensor 50 and the output signal of the amplifier 88 is fed to the amplifier 70. The switch LD 2.1 closes the circuit for the relays CR 2 and STD 2.

The output of amplifier 88 is positive if ¹ AI> ¹ AIm '*** ^ne «* ^tiv ' ^{if 1} AI < ¹ AIm '

* whom the rolls in the roll stand 2 is running too fast, I _A1 ^<1 Ai- UB * ^dae rolling train is subjected to. The roll stand 1 therefore does less work and I _A1 becomes smaller than I ^ -j _B

A negative voltage at the output of amplifier 88 causes a

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Rotation of the motor 72, which moves the potentiometer 74 in the direction of reducing the speed of the motor 24. The sliding contact of the potentiometer 74 supplies the speed setpoint ni for the motor 24, the speed of which is controlled by field weakening. The change in the speed of the motor 24 has an effect on the frame 1. If the motor 24 exerts less tension on the whale material, the tension will decrease and 1. ^ will increase until I..j = 1 ^ ₁ .

If the motor 24 of the roll stand 2 runs too slowly compared to the motor of the roll stand 1, the motor of the roll stand 1 pushes the rolling stock and exerts a negative tensile stress or a thrust force on the rolling stock. The load on the roll stand 1 is greater and thus 1. ^ > * a1b * ^{The AuB} e ^a Dg of the amplifier 88 is positive in this case and the motor 72 drives the potentiometer 74 in the sense of increasing the speed of the motor 24, up to 1 ^ ₁ = I » _1B .

Of course, the rolling stock continues uninterruptedly in the same direction on the roll stand 3 As soon as the rolling stock approaches the roll stand 3, the transport time for the Device T1 taking into account roll stand 2 is actuated, switch TD 2.1 switches off the arrangement for roll stand 1 and the normally closed switch TD 2.2 is opened. The process is now repeated between the roll stand and the Walx framework 3

The operating state I _A1 < ¹ ^ Im ^{is shown in FIG. 2} .

Curve A represents the armature current without correction, curve B the armature current when the invention is applied. After the whale material has entered the whale frame 1 and the transient process has subsided, the armature current required for rolling the rolled material _{results at t 1.} At t «the rolling stock has entered the roll stand 2 and at t« a static course of the armature treadmill is regained.

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At time t, the control device according to the invention conducts the correction of the tension error ΔΤ.

The operating state I ...> L ·. is shown in FIG.

In the same way, the facility starts at t. the To determine and correct error ΔC due to pressure.

Once the motors have been set to their correct speed have been, the operator can switch off the arrangement for automatic speed correction and the rolling stock roll continuously.

4 claims
3 figures

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Claims (2)

- 9 - VPA 72/8355 Pat ent claims /1. Disorder for the tensile or thrust-free rolling of rolling stock in a multi-stand roller train with speed-controlled Individual drives whose speeds can be preset and to avoid looping between the scaffolding are in a fixed relationship to each other, with one that records and stores the anchor rom for each scaffold drive Device from which the stored value is called up and compared with the actual value when the rolling stock has entered the next stand, with the difference between the stored value and the actual value of the armature current is fed to the speed controller of the drive for the following stand as a correction value, characterized in that each stand (1,2) has a load sensor (48,50) is assigned that the armature current measuring device (78) via a switching element (CR 1.1), which is closed depending on the load sensor (48) and depending on the one for the transport of the rolling stock between device (T1) that determines the time required for each two adjacent scaffolding is opened, with which the armature current storing device (80) is connected and that the output of a is the difference between the stored and the comparator (88) forming the measured armature current is connected to the speed setpoint generator (62) for driving the following frame (2) via a switching element (LD 2.2) which, depending on the load sensor (50 ) is closed. 2. Arrangement according to claim 1, characterized in that the Load filler (48,50) a summing amplifier (52 or 56), one input of which is connected via an integrator (54 or 58) to a tachometer generator (36 or 38) coupled to the drive (22 or 24) and the other one Input one proportional to the armature current (I ... or Ι »ο) Size is supplied, and a downstream of the amplifier - 10 - 409807/0816 - 10 - VPA 72/8355 Contains relay (LD1 or LD2). Arrangement according to claim 1, characterized in that
which the Traneporizeil; determining device (T1, T2)
an integrator (92, 100) which can be connected to the tachometer generator (36 or 38) via a switching element (STD 1.1), a
the output signal of the integrator with an adjustable voltage comparing device (102) and a relay
(TD1 or TD2). Arrangement according to Claim 3, characterized in that in the common excitation current one of the switching elements (CR 1.1) actuating relay (CR 1) and another relay (STD 1) actuating the switching element (STD 1.1) is a series circuit from the relay switches (TD 2.1, LD 1.1) and additionally a switch in the excitation circuit of the relay (CR 1) (TD 1.1) of the relay (TD1) is arranged. 409607/081 6 Blank page