JPS61209707A - Method for controlling operation of skew rolling mill - Google Patents

Abstract

PURPOSE:To improve the productivity of a titled mill by controlling operation by increasing a piercing speed through the increase of the work of a drive roll shoe when the actual piercing speed of a stock to be rolled remains less than an aimed value. CONSTITUTION:A rolling roll 21 is driven by a DC motor 29 and is controlled in its rotational speed by an arithmetic control unit 47. A drive roll shoe 31 is slantly arranged at a prescribed advance angle with respect to the axial direction of a pipe stock 32. Further, hot billet detectors 48A, 48B are provided to the outlet side of a mill, and the piercing speed of stock 32 is detected by a speed detector 48 based on the detected results of the detectors 48A, 48B. The rotational speed of shoe 31 is controlled synchronously with that of the roll 21 throughout the whole length of stock 32. In this way, the slip between the shoe 31 and the round billet or the stock 32 is prevented. In this state, the piercing speed of pipe stock 32 is increased, and the productivity is improved, by controlling the operation by increasing the work of shoe 31 for the stock 32.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inclined rolling mill used for manufacturing seamless pipes such as seamless steel pipes.

[Prior Art] In general, in the process of perforating seamless steel pipes, two rolling rolls having an entry side angle and an exiting side angle are arranged at an angle at a constant advance angle, and a fixed shoe and a roller shoe are placed between the rolling rolls. An inclined rolling mill with guide shoes such as the following is used.

FIG. 6 is a front view showing the rolling roll 1, the plug 2, the raw tube 3, and the fixing shoe 4 in the inclined rolling mill. Base pipe 3
is pulled in the tangential direction by the circumferential speed of the rolling roll 1, collides with the fixed shoe 4, and slides, producing a worn portion on the surface of the fixed shoe 4. Further, on the surface of the fixing shoe 4, a fine rack is generated, which is considered to be caused by thermal stress. These worn parts and cracks that occur on the surface of the fixing shoe 4 tend to cause shoe seizure between the base tube 3 and the fixing shoe 4, and as a result, outer surface scratches called shoe scratches occur on the surface of the base tube 3, causing scratches on the surface of the base tube 3. The quality and properties of the pipe 3 are deteriorated. Further, it is necessary to stop the rolling mill and take care of the burned-out portion of the fixed shoe 4 or replace the fixed shoe, and these maintenance operations reduce the productivity of the rolling line and increase production costs.

FIG. 7 is a front view showing an inclined rolling mill proposed in Japanese Utility Model Application Laid-Open No. 110509/1983 to eliminate the inconvenience caused by the use of the fixed shoe 4. This inclined rolling mill uses roller shoes 10 that can guide the raw tube 3 without causing a large slip between the raw tube 3 and the raw tube 3. however.

This roller shoe lO is an idle roller,
Although it rotates, it is not forced to drive, but □
In this case, since the roller shoe lO is an idle roller, when the raw tube 3 escapes into the gap between the rolling roll 1 and the roller shoe lO, rolling stops without the roller shoe lO pulling out the raw tube 3. This may cause a sticking phenomenon. In order to prevent the occurrence of the above-mentioned sticking force phenomenon, it is possible to insert a guide plate 11 between the rolling roll 1 and the roller shoe 10, but in that case, the same problem as with a fixed shoe will occur, and the roller shoe If the effect of using lO cannot be obtained and the length of the roller shoe 10 is to be the same as that of the fixed shoe, the roller shoe 10
This results in insufficient axial strength against the thrust force acting on the shaft, and a backup roll 12 is required.

[Problems to be Solved by the Invention] That is, the conventional inclined rolling mill cannot stably guide the material to be rolled during rolling and perform smooth rolling due to its compact structure.

Therefore, the present applicant has proposed an inclined rolling mill according to Japanese Patent Application No. 58-175211 in order to solve the above-mentioned conventional disadvantages. This inclined rolling mill is constructed by arranging forcibly driven drive roller shoes at an angle on the sides of a rolling area formed by rolling rolls. According to this inclined rolling mill, the drive roller shoes apply a rotational force to the material to be rolled, so that the material to be rolled is guided by the drive roller shoes and brought to the side of the adjacent rolling roll. The compact structure allows smooth rolling.

Incidentally, in recent years, there has been a significant demand for improved productivity in seamless steel pipe manufacturing lines, and it is desired to increase the perforation speed of the above-mentioned inclined rolling mill.

An object of the present invention is to appropriately control the operation of an inclined rolling mill having the drive roller shoes described above, and to increase the perforation speed without impairing the quality properties of the rolled material or the life of the shoes. .

[Means for Solving the Problems] The present invention provides a set of rolling rolls in which each of the rolling rolls is arranged inclined at a constant advance angle, and the rolling roll is forcibly driven to the side of the rolling bond area formed by each rolling roll. A method for controlling the operation of an inclined rolling mill in which drive roller shoes are arranged in an inclined manner at a constant advance angle, and the method is to control the operation of an inclined rolling mill in which a deviation in the circumferential speed of both the drive roller shoes and the material to be rolled is within an allowable deviation range. As a condition, when the actual drilling speed of the rolled material does not reach the predetermined target drilling speed, the work amount of the drive roller shoe on the rolled material is increased and the actual drilling speed is controlled to increase. It is.

[Function] According to the present invention, the perforation speed of the rolled material is increased and controlled to be higher than the target perforation speed by the work of the drive roller shoe. At this time, the drive roller shoe is driven in a state in which slippage occurring between the drive roller shoe and the material to be rolled is suppressed within an allowable range, so that the material to be rolled can be reliably and stably supported.

That is, according to the present invention, it is possible to increase the drilling speed without impairing the quality properties of the rolled material or the life of the shoe.

[Example] FIG. 4 is a side view showing an example of an inclined rolling mill to which the present invention is applied, and FIG. 5 is a front view showing a rolling state by the inclined rolling mill.

In this inclined rolling mill, a pair of two rolling rolls 21 are arranged on the left and right, and a plug 23 supported by a plugper 22 is arranged between the rolling rolls 21. The rolling roll 21 has an entrance side angle and an exit side angle, and is arranged inclined at an advance angle of, for example, 10 degrees to 12 degrees, and is capable of moving forward in the axial direction while rotating the round steel piece z5 on the trough 24 in the circumferential direction. There is. Note that the round steel piece 25 on the trough 23 is pushed in by the bushing 27 while being guided onto the cannon 26, so that it can be bitten by both rolling rolls 21.

The rolling roll 21 can be driven by a DC motor 29 via a speed reducer 28 .

30 is a rotary generator, and the rotation speed N of the rolling roll 21 is
m can be detected. This detection result is transmitted to an arithmetic and control unit 47, which will be described later.

A pair of drive roller shoes 31 are arranged at upper and lower positions between the two rolling rolls 21 . From the center of the drive roller shoe 31 in the axial direction,
It has an entrance surface angle that reduces the outer diameter toward the entrance end, and an exit surface angle that reduces the outer diameter from the center in the axial direction toward the exit end.

Further, the drive roller shoe 31 is arranged so that its central axis is inclined at a constant advance angle of, for example, 3 degrees to 4 degrees with respect to the axial direction of the raw pipe 32, and the drive roller shoe 31 is arranged so that its central axis is inclined at a constant advance angle of 3 to 4 degrees with respect to the axial direction of the raw pipe 32, and the drive roller shoe 31 has a speed along the advancing direction of the raw pipe 32 on its peripheral surface. It is possible to obtain the ingredients.

The shaft 33 of the drive roller shoe 31 is fixed by a bearing 34 and a support stand 35, and a wedge 37 is fixed to the base 36 of the support stand 35 by a port 38 so that it can be easily removed. The upper surface position of the drive roller shoe 31 can be finely adjusted by rotating the screw shaft 40 by the hydraulic motor 39 and moving the tapered table 41 to raise and lower the lower frame 42. Furthermore, locking after adjustment is performed by a hydraulic cylinder 43.

Further, the drive roller shoe 31 can be driven by a DC motor 45 via a universal joint 44 . 46 is a rotary generator, and drive roller shoe 3
The rotational speed Ns of 1 is the detection tube's function. In addition,
The drive roller shoe 31 may be driven by a hydraulic motor whose speed can be controlled.

The above-mentioned inclined rolling mill is equipped with a control circuit as shown in FIG. 47 is an arithmetic and control unit.

48 is a perforation speed detector, and hot mass detectors 48A are arranged at a certain distance from each other on the exit side of the rolling mill.
, 48B, the actual drilling speed Vo of the raw pipe 32
can be detected.

49 is a setting device for the outer diameter Do of the raw pipe 32, 50 is a setting device for the outer diameter Dm of the rolling roll 21, 51 is a tribe roller cage,
-3117) Outer diameter Ds setting device, 52 is a speed control device,
53 is a thyristor power supply device.

Hereinafter, the control procedure by the arithmetic and control unit 47 will be explained with reference to FIG.

First, the arithmetic and control device 47 determines each rotational speed N5 (N s L,
N s R) is set by the following equation (1) or (2).

N5=(No・Do)/Ds...(1)Ns
= (Nm ・Dm) /D s (2) That is, the arithmetic and control device 47 determines the rotational speed NO1 of the raw pipe 32.
Outer diameter Do, outer diameter Ds of drive roller shoe 31
or the rotation speed Ns of the drive roller shoe 31 based on the rotation speed Nm of the rolling roll 21, the outer diameter Dm of the rolling roll 21, and the outer diameter Ds of the drive roller shoe 31, which are correlated with the rotation speed No. of the raw pipe 32. Set.

Next, the arithmetic and control unit 47 transmits the rotational speeds NsL and NsR of the drive roller shoes 31 set as described above to the speed control devices 52 corresponding to the left and right drive roller shoes 31, and The DC motor 45 of the drive roller shoe 31 is driven and controlled through the drive roller shoe 31. Under this condition, biting of the round steel piece 25 is started,
It is possible to pray for the raw pipe 32. FIG. 3 is a diagram showing a pattern of the rotational speed Nm of the rolling roll 21 and a pattern of the rotational speed Ns of the drive roller shoe 31. That is, the rotational speed Ns of the drive roller shoe 31 is controlled in synchronism with the rotational speed Nm of the rolling roll 21 over the entire length of the raw tube 32. As a result, the drive roller shoe 31 rotates at a circumferential speed that matches the circumferential speed of the round steel piece 25 and the raw pipe 32.
5. Those round steel pieces 25. without causing slippage between them and the raw pipe 32. The raw pipe 32 can be stably supported.

Here, at the tip and rear ends of the round steel piece 25 and the raw pipe 32, the rotational speed of the rolling roll 21 is set higher than usual in consideration of the biting property of the round steel piece 25 and the raw pipe 32 with respect to the rolling roll 21. Zooming control is applied to reduce the brightness by 20-30%. In this example, the drive roller shoe 3
1 is also controlled to follow the zooming control of the rolling roll 21 as shown in FIG.

Note that the DC motor 4 of the drive roller shoe 31
The actual rotational speed Ns of No. 5 is fed back to the speed control device 52, so that the driving state of the DC motor 45 can be feedback-controlled.

Incidentally, in order to control the rotational speed of the drive roller shoe 31, it is necessary to maintain the amount of work of the left and right DC motors 45 within a certain allowable load range. This is because if the current ratio N1c of one of the DC motors 45 becomes larger than the other, speed control by one of the DC motors 45 becomes impossible. Here, the amount of work of the DC motor 45 is determined by the respective rotational speeds NsL and NsR of the left and right drive roller shoes 31 and the distances L1 and L2 between the left and right drive roller shoes 31 as shown in FIG.
is determined as the main factor, and its magnitude is understood as the current values IL and IR of each DC motor 45. Therefore,
In this embodiment, during rolling of the blank pipe 32, current values IL and IR of each DC motor 45 are detected, and the detection results are transmitted to the arithmetic and control unit 47. The arithmetic and control unit 47 calculates the difference [I L - I R1] between the current values, and when the calculation result exceeds a certain value (for example, when one excessive current value exceeds the rated value 102), the current The rotational speed of the drive roller shoe 31 corresponding to the direct current motor 45 with an excessive value is reduced by ΔN, and both drive roller shoes 3
Adjust the rotational speeds NsL and NsR of 1. In addition, when the above calculation result exceeds a certain value, the distances L1 and L2 between the left and right drive roller shoes 31 may be adjusted.As a result, the workload of the left and right DC electric motors 945 is balanced, and these DC motors It becomes possible to stabilize the speed control of the drive roller shoe 31 by the drive roller shoe 45.

Further, the arithmetic and control unit 47 calculates the average value [(I
L+I R)/2] is calculated for each raw tube 32, and learning control is performed as the average current value of both DC electric pot machines 45 in the same lot of raw tubes 32. This average current value is the optimum current value of the DC motor 45 for the raw pipe 32 of the same lot, that is, the reference rotation speed NsL of the drive roller shoe 31.
%NsR is stored as a command value to be given to the DC motor 45.

Therefore, in the present invention, even if the circumferential speed of the drive roller shoe 31 and the circumferential speed of the round steel piece 25 and the raw pipe 32 do not completely match, the deviation between them is kept within a certain allowable deviation range. It is sufficient that the rotational speed Ns of the drive roller shoe 31 is synchronously controlled to the rotational speed Nm of the rolling roll 21, ultimately to the rotational speed No of the element v32, that is, the above deviation is within the range of allowable deviation. This is because, as long as the drive roller shoe 31 fits within the housing, there will be no slippage between the round steel piece 25 and the raw tube 32, which would be inconvenient in terms of quality and rolling operation.

Furthermore, in the present invention, the actual drilling speed Vo of the raw pipe 32 is set to a predetermined target on the condition that the deviation between the circumferential speeds of the drive roller shoe 31 and the raw pipe 32 falls within the allowable deviation range as described above. When the drilling speed Va has not been reached, the amount of work of the drive roller shoe 31 on the raw pipe 32 is increased, and the actual drilling speed vO is controlled to increase. The actual drilling speed Vo of the raw pipe 32 is determined by the drilling speed detector 4 as described above.
8 is actually measured. The target drilling speed Va of the blank pipe 32 is set to, for example, 95% of the theoretical drilling speed Vt determined by the following equation (3).

Vt = π m Nm −Dm @S
i na/[lOa i −·− (3) where α is the advance angle of the rolling roll 21, and i is the reduction ratio of the speed reducer 28. The theoretical perforation speed Vt is a value where the perforation efficiency by the rolling roll 21 is defined as toox. What is the amount of work done by the drive roller shoe 31?

Speed increase control is possible by increasing the rotational speed Ns of the drive roller shoe 31 by the DC motor 45 and adjusting the distances Ll and L2 between both drive roller shoes 31. As a result, in this inclined rolling mill, the perforation speed Vo of the raw pipe 32 can be changed to the target perforation speed Va by the work of the drive roller shoe 31 without impairing the quality properties of the raw pipe 32 or the life of the drive roller shoe 31. It becomes possible to increase the speed and improve the productivity of the rolling line.

As described above, according to the above embodiment, the drive roller shoe 31 is synchronously controlled with respect to the rolling roll 21 and ultimately the raw tube 32, and the slip occurring between the drive roller shoe 31 and the rolling roll 21 is prevented. It becomes possible to keep the rolling value to zero or within a permissible range, thereby improving the rolling workability of the round steel piece 25 and the raw pipe 32.

It is possible to improve the quality of the raw tube 32 and the life of the drive roller shoe 31. Furthermore, the work of the drive roller shoes 31 makes it possible to increase the perforation speed of the raw pipe 32 and improve the productivity of the rolling line.

According to the results of implementation by the present inventor, the present invention allows the raw pipe 32
IO! It is possible to reduce the first stick force phenomenon occurring in the raw tube 32 by 5z, and extend the life of the drive roller shoe 31 by 10%. In addition, by eliminating the need to repair shoe defects, productivity has increased by 2.
It is recognized that the productivity is improved by 3z by increasing the drilling efficiency of the raw pipe 32.

[Effects of the Invention] The present invention has a set of rolling rolls arranged at an angle with a constant advance angle, and a drive roller shoe that is forcibly driven to the side of the rolling area formed by each rolling roll. A method for controlling the operation of an inclined rolling mill which is arranged at an inclined angle with a constant advance angle. When the actual drilling speed of the material does not reach a predetermined target drilling speed, the amount of work of the drive roller shoe on the rolled material is increased to increase the actual drilling speed. Therefore, it is possible to appropriately control the operation of an inclined rolling mill having drive roller shoes and increase the perforation speed without impairing the quality properties of the rolled material or the life of the shoes.

[Brief explanation of the drawing]

FIG. 1 is a control system diagram schematically showing an embodiment of the present invention;
Figure 2 is a flowchart showing the control procedure in the same embodiment;
4 is a partially cutaway side view showing an example of an inclined rolling mill to which the present invention is applied, and FIG. 5 is a diagram showing the control state in the same embodiment. FIG. FIG. 6 is a front view showing the rolling state of a conventional inclined rolling mill using fixed shoes. FIG. 7 is a front view showing the rolling state of a conventional inclined rolling mill using roller shoes. It is. 21... Rolling roll, 25... Round steel piece, 29...
DC motor, 30... Rotating generator, 31... Drive roller shoe, 32... Base tube, 45... DC motor, 46... Rotating generator, 47... Arithmetic control unit, 4B ...Drilling speed detector, 52...Speed control device. Agent Patent Attorney Osamu Shiokawa 1 Figure 2 Figure 3 wL Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] (1) Each of the rolling rolls forming a set is arranged at an inclination at a constant advance angle, and a drive roller shoe that is forcibly driven is arranged at an inclination at a constant advance angle on the side of the rolling area formed by each roll. A method for controlling the operation of an inclined rolling mill comprising: controlling the actual perforation speed of the material to be rolled in advance on the condition that the deviation of the circumferential speed of both the drive roller shoe and the material to be rolled falls within an allowable deviation range; A method for controlling the operation of an inclined rolling mill, characterized in that when a predetermined target perforation speed has not been reached, the amount of work of a drive roller shoe on the material to be rolled is increased, and the actual perforation speed is controlled to increase.