SU506448A1 - The method of adjusting the average wall thickness of the pipe in the reduction mill - Google Patents

Description

Chip struasturpa scheme for regulating the thickness of the walls of pipes.

The workpiece 1 is rolled by a reduction mill 2 into the finished pipe 3. The speeds of the rolls are varied with engine 4 through speed control device 5. The number of engines 4 is determined by the type of mill drive. In the particular case, when the differential group drive as engines 4 can be used a single engine (. Auxiliary). The scheme with one engine is shown only as the simplest for the image. With a different type of drive, the essence of the method does not change.

The signals to control unit 5 are received via two channels 6 and 7. Channel 6 receives a control signal, a prolortional deviation of the draw l from a predetermined value, determined in the comparison unit 8. The exhaust tube is determined by the meter 9 or on the basis of simultaneous velocity measurements rolled VQ and V at the entrance and exit of the mill (K Vi / Vo), or in some other way, for example, based on measurements of the length of the pipe LI and the billet LO: I LI / LO.

The channel 7 receives the control signal from the multiplication unit 10. This signal is proliferation from the deviation of the average wall thickness of the next workpiece Sg, from a predetermined value determined in the comparison unit 11. The proportionality factor by which the deviation of the wall thickness of the workpiece is multiplied or leredatoma the coefficient Kp for the control signal in channel 7 is determined by the adder 12. In turn, two signals are added to the inputs 13 and 14 of the adder 12, namely, the signal of the initial setting Ko and the additional correction signal from the reminder The integrating block 15. The input of the block 15 receives sigpal from the comparator block 16, in which the deviation of the average wall thickness of the finished pipe Si / from the given value 5 |

The proposed method is implemented as follows. Initially (prior to the start of procaping and automatic adjustment) some calculated speeds of the rolls in the mill 2 are installed, the signals corresponding to the specified values of the pipe stretching and wall thickness of the workpiece and the finished pipe are entered into the blocks of comparison 8, 11, 16; the adder 12 is entered with the initial value of the inextricable coefficient; the output of block 15 is set to zero.

Before the first pipe is rolled, the control signals to the device 5 through channel 6 are allowed, and channel 7 is blocked.

When rolling the first pipe () or several pipes, the initial setting of the mill is carried out and the pipe stretching is measured with the aid of meter 9. Using the comparison unit 8, the obtained stretch pressure is compared with the specified value. If the obtained value of the exhaust differs from the specified value, then the corresponding signal from channel 6 through the device 5 and the engine 4 changes the speed of the mill rolls with simultaneous or subsequent measurement of the pipe stretch to such an extent that the deviation of the exhaust is reduced to

to zero. After reaching a given amount of stretching, channel 6 is blocked and channel 7 is opened.

Then, the average wall thickness S ,,, - of each next billet is measured; it is compared with the set value So back to the power of block 11 and, before rolling this billet, the speeds of the shaft are changed using a control signal through channel 7. The control signal to channel 7 (and therefore, the change in the speed of the engine 4 relative to the level at which a given stretch was ensured) is proportional to the deviation of the average wall thickness of the workpiece from the given value So back and the ratio of the transfer coefficient Ki; . For the first of these blanks, the transfer coefficient K and has the initial value K o, set at the inlet 13 of the adder 12. After rolling this billet, measure

average wall thickness Si; the pipe corresponding to it is compared in the comparison unit 16 with the specified value. If the corresponding deviation is not zero, then the initial value of the transfer coefficient K is chosen inaccurately and it is necessary to correct it. Depending on the amount of deviation Su from before rolling the next pipe, the initial value of the transfer ratio is adjusted.

coefficient. A correction signal is generated and stored by block 15 and input 14 to the adder 12.

The correction of the transfer coefficient in the control signal circuit, i.e., the ratio between the roll speed change and the baking thickness deviation of the workpiece, is carried out by rolling subsequent pipes in a similar way if the average wall thickness Si / a given Si3a value is not equal. After performing the correction, before any significant additional changes in the parameters of the rolling process occur, the regulation of the pipe wall thickness will be

to reduce to a change in the speed of the engine 4 before rolling each successive billet so that the deviation of this speed from the mode at which the target value was reached was proportional to

deviation of the average wall thickness of the workpiece and the adjusted value of the gear ratio.

With the gradual accumulation of additional parameters of the rolling process parameters, the thickness of the pipe walls will begin to deviate.

from the given value. In accordance with the value of this deviation, the automatic correction and gear ratio will again be made in a similar way. After interruptions in the mill operation, at the resumption of rolling, the wall thickness of the pipes can be adjusted either immediately depending on the deviations of the thickness of the workpiece, or after additional checking the setting of the mill for a given stretch, as foreseen by the first of the considered adjustment steps. The appropriate choice will be determined by the specific conditions.

Claims (1)

Invention Formula The method of regulating the average thickness of the steaks of the pipes in the reduction mill by changing the speeds of the rolls in the cages with stretching the pipes and the average thickness of the sevka behind the rotobiok, characterized in that, in order to reduce the deviations of the average thicknesses of the pipe walls and increase their quality, reduce to a small value the deviations of the pipe stretching from the specified value, after which the deviation from the specified average thickness is measured the walls of each billet and during the period before its rolling change the speeds of the rolls relative to the value achieved at the elimination of the stretching deviation by an amount pronounced to the measured deviation of the wall thickness of the billet, Nichle nakrokki billet this proportionality is adjusted for rolling the next workpiece depending on the deviation from the predetermined level of the average wall thickness of the previous finished pipe. 0, ) the gap I ass