A control method for a horizontal roller reversing rolling mill

Abstract

The present invention belongs to the technical field of steel rolling, and in particular relates to a control method for a horizontal roller reversible rolling mill. During the first rolling pass after the coarse slag machine rolls are changed, the horizontal rollers are rolled at a speed lower than the maximum speed V C The speed V of biting steel, rolling and throwing steel; among which: the maximum speed V C The invention controls the horizontal rollers to uniformly speed the horizontal rollers after roller change to achieve biting, rolling and lifting of the rolled piece, thereby preventing the rolled piece from slipping and improving the qualified rate of the finished plate shape.

Description

Technical Field

[0001] The invention belongs to the technical field of steel rolling, and in particular relates to a control method for a horizontal roller reversible rolling mill. Background Art

[0002] Hot rolling mills consist of a roughing mill and a finishing mill, which work together to produce rolled products. To save production costs, the roughing mill uses a reciprocating rolling process. This requires frequent changes in the direction of the rollers' rotation, which often necessitates reciprocating speeds.

[0003] The rolls of the roughing mill include vertical rolls and horizontal rolls, and the vertical rolls and horizontal rolls need to repeatedly go through 0-speed increase-speed decrease-0; specifically, Figure 1 As shown, during the first rolling, the horizontal roller speed gradually increases to the maximum rolling speed V C , then V C Roll at a constant speed, and finally gradually reduce the speed to 0 (because reversing is required).

[0004] However, the rough rolling mill needs to replace the rolls during the process. In actual use, it is found that when the rolled piece is rolled after the horizontal rolls are replaced, serious plate shape defects occur, resulting in a significant decrease in the qualified rate of the finished plate shape.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] Severe flatness defects, leading to a significant drop in the finished product flatness and wedge shape qualification rates, are primarily caused by rolling slippage after roll change. Slippage also significantly impacts equipment life, shortening the replacement cycle for all wearing parts and significantly increasing equipment maintenance costs. In the most severe cases, slippage can lead to a major equipment accident, such as breaking the drive coupling.

[0007] The slippage during the roughing mill rolling process is mainly concentrated in the early stage of the new work roll replacement. The main reasons are as follows:

[0008] 1. Low surface friction on new work rolls: The surface finish of new rolls is too high. The friction coefficient between the roll surface and the workpiece surface in the deformation zone during the workpiece bite and rolling process is low. The metal flow velocity of the workpiece is lower than the linear velocity of the rolls, and the metal flow direction changes, interrupting the stable and continuous deformation process. This causes the workpiece to swing left and right along the roll axis during the rolling process.

[0009] 2. Damage to the oxide film on the work rolls: Due to the frequent contact between the newly installed work rolls and the hot workpiece during rolling, oxidation occurs on the roll surface and a layer of oxide film continuously forms on the roll surface. The formation and stability of the oxide film increases the roll friction coefficient. However, the stable formation of the oxide film requires a stable rolling state. Rolling slippage can severely damage the developing work roll oxide film. Since the oxide film's adhesion to the roll is not strong enough during its growth stage, it will flake off when the workpiece slips. Conversely, localized flakes of the oxide film on the work roll surface cause uneven localized friction during rolling, exacerbating the slippage of the workpiece during rolling and further causing rolling instability. This is manifested in uneven black spots on the surface of the rolled intermediate billet, accompanied by a noticeable S-bend.

[0010] 3. The rolling tension in odd passes is destroyed. The vertical roller participates in width control in odd passes. The vertical roller and the horizontal roller form micro-tension continuous rolling. When the newly replaced working roller slips, the rolling deformation speed decreases and the set tension is destroyed. The micro-tension originally applied by the vertical roller to the horizontal roller to stabilize the rolling becomes a destructive force pushing toward the horizontal roller, aggravating the rolling slip.

[0011] In order to solve the technical problems existing in the prior art, the present invention provides a control method for a horizontal roller reversible rolling mill. The present invention controls the horizontal rollers to uniformly speed after the rollers are changed to achieve biting, rolling and lifting of the rolled piece, thereby avoiding slipping of the rolled piece and improving the qualified rate of the finished plate shape.

[0012] The present invention includes the following technical solutions:

[0013] The present invention provides a control method for a horizontal roller reversing rolling mill, which is characterized in that:

[0014] In the first rolling pass after the coarse slag mill roll change, the horizontal roll is rolled at a speed lower than the maximum speed V C Speed ​​V for biting, rolling and throwing steel;

[0015] Where: Maximum speed V C is the speed of the horizontal roller during rolling.

[0016] Furthermore, the speed 1m / s≤V≤1.5m / s.

[0017] Furthermore, the maximum speed is 3m / s≤V C ≤4.5m / s.

[0018] Furthermore, the method comprises a vertical roller and a horizontal roller, wherein the speed of the vertical roller is lower than the speed of the horizontal roller, and is characterized in that the method comprises the following steps:

[0019] The first rolling pass: the speed of the horizontal roller when biting the steel is V, the horizontal roller rolls at a constant speed of V, and the speed of the horizontal roller when throwing the steel is V.

[0020] Furthermore, the method further comprises the following steps:

[0021] Nth rolling pass: The horizontal roller is rolled at a speed less than the maximum speed V C Gradually increase the speed to the maximum speed V C , the horizontal roller is running at a speed less than the maximum speed V C Throwing steel at a speed of

[0022] Where: N ≥ 2, N is a positive integer.

[0023] Furthermore, during the odd-numbered rolling passes, the vertical rolls are used for rolling;

[0024] During rolling with an even number of passes, the vertical rolls do not perform rolling.

[0025] Furthermore, the speed of the vertical roller is lower than the speed of the horizontal roller.

[0026] Furthermore, in the first rolling pass, the speed of the horizontal roller when the horizontal roller bites the steel is V, the horizontal roller rolls at a constant speed of V, and the speed of the horizontal roller when the horizontal roller throws the steel is V;

[0027] Second pass rolling: horizontal rollers at a speed less than the maximum speed V C Gradually increase the speed to the maximum speed V C , the horizontal roller is running at a speed less than the maximum speed V C Throwing steel at a speed of

[0028] The third rolling pass: the horizontal roller is rolled at a speed less than the maximum speed V C Gradually increase the speed to the maximum speed V C , the horizontal roller is running at a speed less than the maximum speed V C Throwing steel at a speed of

[0029] The fourth rolling pass: the horizontal roller is rolled at a speed less than the maximum speed V C Gradually increase the speed to the maximum speed V C , the horizontal roller is running at a speed less than the maximum speed V C Throwing steel at a speed of

[0030] The fifth rolling pass: the horizontal roller is rolled at a speed less than the maximum speed V C Gradually increase the speed to the maximum speed V C , the horizontal roller is running at a speed less than the maximum speed V C Throwing steel at a speed of

[0031] After the fifth rolling pass, rough rolling is completed.

[0032] Furthermore, the deformation amount of the horizontal roller in the second rolling pass = the deformation amount of the horizontal roller in the fourth rolling pass = the deformation amount of the horizontal roller in the fifth rolling pass = 1;

[0033] The deformation of the horizontal roller in the first rolling is 85% l, and the deformation of the horizontal roller in the second rolling is 90% l;

[0034] Among them: 3l+85%l+90%l=L, L is the total deformation of the thickness of the rolled piece to be rolled.

[0035] Furthermore, within one roll changing cycle of the roughing mill, the finishing mill performs twenty roll changes;

[0036] Maximum speed V of horizontal roll after roll change in roughing mill C =3m / s;

[0037] After the first roll change in the finishing mill, the maximum speed V of the horizontal roll of the roughing mill is C =3.5m / s;

[0038] After the second roll change in the finishing mill, the maximum speed V of the horizontal roll of the roughing mill is C =4m / s;

[0039] After the first roll change in the finishing mill, the maximum speed V of the horizontal roll of the roughing mill is C =4.5m / s;

[0040] From then on until the next roll change of the roughing mill, the maximum speed of the horizontal roll of the roughing mill is V C =4.5m / s.

[0041] By adopting the above technical solution, the present invention has the following advantages:

[0042] 1. The present invention controls the horizontal rollers to uniformly speed after roller change to achieve biting, rolling and lifting of the rolled piece, thereby preventing the rolled piece from slipping and improving the qualified rate of the finished plate shape.

[0043] 2. The first-pass rolling speed of the present invention is V = [1 m / s, 1.5 m / s], which can ensure that there is no slipping during the first-pass rolling, improve the qualified rate of the finished plate shape, and also improve safety.

[0044] 3. After the first pass, the present invention uses a horizontal roller at a speed less than the maximum speed V C Gradually increase the speed to the maximum speed V C , the horizontal roller is running at a speed less than the maximum speed V C Throwing steel at a high speed can not only prevent slipping, but also increase the rolling speed and improve production output. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 A schematic diagram of the speed of the horizontal rollers of a prior art roughing mill described in the background of the present invention;

[0047] Figure 2 Schematic diagram of the speed of the horizontal rollers of the roughing mill in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0049] This embodiment provides a control method for a horizontal roller reversing rolling mill, such as Figure 2 As shown in the figure, in the first rolling after the coarse slag mill roll change, the horizontal roll is rolled at a speed lower than the maximum speed V C Speed ​​V for biting, rolling and throwing steel;

[0050] Where: Maximum speed V C is the speed of the horizontal roller during rolling.

[0051] Because slippage mainly occurs in the first pass, the thickness and width of the rolled piece do not change at this time, and it is at the largest size stage. The tension generated when the rolled piece passes through the vertical roll and horizontal roll in sequence is the largest, and the slippage phenomenon is the most serious. By controlling the speed of the horizontal roll in the first pass, the slippage of the rolled piece is avoided, the qualified rate of the finished plate shape is improved, and safety is also improved.

[0052] Furthermore, the speed 1m / s≤V≤1.5m / s.

[0053] Furthermore, the maximum speed is 3m / s≤V C ≤4.5m / s.

[0054] Furthermore, the method comprises a vertical roller and a horizontal roller, wherein the speed of the vertical roller is lower than the speed of the horizontal roller, and is characterized in that the method comprises the following steps:

[0055] The first rolling pass: the speed of the horizontal roller when biting the steel is V, the horizontal roller rolls at a constant speed of V, and the speed of the horizontal roller when throwing the steel is V.

[0056] Furthermore, the method further comprises the following steps:

[0057] Nth rolling pass: The horizontal roller is rolled at a speed less than the maximum speed V C Gradually increase the speed to the maximum speed V C , the horizontal roller is running at a speed less than the maximum speed V C Throwing steel at a speed of

[0058] Where: N ≥ 2, N is a positive integer.

[0059] Furthermore, during the odd-numbered rolling passes, the vertical rolls are used for rolling;

[0060] During rolling with an even number of passes, the vertical rolls do not perform rolling.

[0061] Furthermore, the speed of the vertical roller is lower than the speed of the horizontal roller.

[0062] Furthermore, in the first rolling pass, the speed of the horizontal roller when the horizontal roller bites the steel is V, the horizontal roller rolls at a constant speed of V, and the speed of the horizontal roller when the horizontal roller throws the steel is V;

[0063] Second pass rolling: horizontal rollers at a speed less than the maximum speed V C Gradually increase the speed to the maximum speed V C , the horizontal roller is running at a speed less than the maximum speed V C Throwing steel at a speed of

[0064] The third rolling pass: the horizontal roller is rolled at a speed less than the maximum speed V C Gradually increase the speed to the maximum speed V C , the horizontal roller is running at a speed less than the maximum speed V C Throwing steel at a speed of

[0065] The fourth rolling pass: the horizontal roller is rolled at a speed less than the maximum speed V C Gradually increase the speed to the maximum speed V C , the horizontal roller is running at a speed less than the maximum speed V C Throwing steel at a speed of

[0066] The fifth rolling pass: the horizontal roller is rolled at a speed less than the maximum speed V C Gradually increase the speed to the maximum speed V C , the horizontal roller is running at a speed less than the maximum speed V C Throwing steel at a speed of

[0067] After the fifth rolling pass, rough rolling is completed.

[0068] The deformation of the rolled piece in each pass is generally maintained by the same amount of pressure applied each time, i.e., the deformation of the horizontal roll in the first pass = the deformation of the horizontal roll in the second pass = the deformation of the horizontal roll in the third pass = the deformation of the horizontal roll in the fourth pass = the deformation of the horizontal roll in the fifth pass = L / 5. Of course, the consistency of the pressure applied each time is only for ease of control; the actual pressure applied each time can vary.

[0069] In order to prevent slipping after roll change: further, the deformation amount of the horizontal roll in the second rolling pass = the deformation amount of the horizontal roll in the fourth rolling pass = the deformation amount of the horizontal roll in the fifth rolling pass = l;

[0070] The deformation of the horizontal roller in the first rolling is 85% l, and the deformation of the horizontal roller in the third rolling is 90% l;

[0071] Among them: 3l+85%l+90%l=L, L is the total deformation of the thickness of the rolled piece to be rolled.

[0072] Based on this, by controlling the downward pressure of the rolled piece, slippage can be avoided.

[0073] Slipping will occur after changing the rolls in the roughing mill, and this can be avoided by controlling the speed, but rolling cannot be done at a low speed all the time. As the rolling time goes by, the friction of the roughing mill will increase, the slipping phenomenon of the roughing mill will decrease, and the rolling will become more stable, so it is necessary to consider increasing the output. Furthermore, within one roll changing cycle of the roughing mill, the finishing mill will change the rolls twenty times;

[0074] Maximum speed V of horizontal roll after roll change in roughing mill C =3m / s;

[0075] After the first roll change in the finishing mill, the maximum speed V of the horizontal roll of the roughing mill is C =3.5m / s;

[0076] After the second roll change in the finishing mill, the maximum speed V of the horizontal roll of the roughing mill is C =4m / s;

[0077] After the first roll change in the finishing mill, the maximum speed V of the horizontal roll of the roughing mill is C =4.5m / s;

[0078] From then on until the next roll change of the roughing mill, the maximum speed of the horizontal roll of the roughing mill is V C =4.5m / s.

[0079] Based on this, rolling stability and output are guaranteed, and there are quantitative standards for speed increase, which is also the most operational.

[0080] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for a horizontal roller reversing rolling mill, characterized in that: In the first rolling pass after the roughing mill roll change, the horizontal rolls are rolled at a speed lower than the maximum speed. Speed biting, rolling and throwing steel; Among them: Maximum speed is the speed of the horizontal roller during rolling.

2. The control method of a horizontal roller reversing rolling mill according to claim 1, characterized in that: The speed V is: 1 m / s≤V≤1.5 m / s.

3. The control method of a horizontal roller reversing rolling mill according to claim 1, characterized in that: Said top speed It is: 3m / s≤VC≤4.5m / s.

4. A control method for a horizontal roller reversing rolling mill according to any one of claims 1 to 3, characterized in that: The speed of the vertical roller is lower than that of the horizontal roller.

5. The control method of a horizontal roller reversing rolling mill according to claim 4, characterized in that: The following steps are also included: No. Pass rolling: horizontal rollers at less than the maximum speed Gradually increase the speed to the highest speed , the horizontal roller is running at a speed less than the maximum speed Throwing steel at a speed of in: , Is a positive integer.

6. The control method of a horizontal roller reversing rolling mill according to claim 5, characterized in that: In odd-numbered rolling passes, vertical rolls are used for rolling; During rolling with an even number of passes, the vertical rolls do not perform rolling.

7. A control method for a horizontal roller reversing rolling mill according to any one of claims 1 to 3, comprising vertical rollers and horizontal rollers, wherein the speed of the vertical rollers is lower than the speed of the horizontal rollers, and wherein: The steps include: First rolling: The speed of the horizontal roller when the horizontal roller bites the steel is , the horizontal roller is at a speed of The rolling is carried out at a uniform speed, and the speed of the horizontal roller throwing steel is ; Second pass rolling: horizontal rollers at a speed less than the maximum speed Gradually increase the speed to the highest speed , the horizontal roller is running at a speed less than the maximum speed Throwing steel at a speed of The third rolling pass: the horizontal roller is rolled at a speed lower than the maximum speed Gradually increase the speed to the highest speed , the horizontal roller is running at a speed less than the maximum speed Throwing steel at a speed of The fourth rolling pass: the horizontal roller is rolled at a speed lower than the maximum speed Gradually increase the speed to the highest speed , the horizontal roller is running at a speed less than the maximum speed Throwing steel at a speed of The fifth rolling pass: the horizontal roller is rolled at a speed lower than the maximum speed Gradually increase the speed to the highest speed , the horizontal roller is running at a speed less than the maximum speed Throwing steel at a speed of After the fifth rolling pass, rough rolling is completed.

8. The control method of a horizontal roller reversing rolling mill according to claim 7, characterized in that: The deformation of the horizontal roller in the second rolling pass = the deformation of the horizontal roller in the fourth rolling pass = the deformation of the horizontal roller in the fifth rolling pass = ; Deformation of the first horizontal roller rolling = , the deformation of the third rolling of the horizontal roller = ; in: , It is the total deformation of the thickness of the rolled piece that needs to be rolled.

9. The control method of a horizontal roller reversing rolling mill according to claim 7, characterized in that: During the roughing mill's roll changing cycle, the finishing mill changes rolls twenty times; Maximum speed of horizontal roll after roll change in roughing mill ; After the first roll change in the finishing mill, the maximum speed of the horizontal rolls in the roughing mill ; After the second roll change in the finishing mill, the maximum speed of the horizontal rolls of the roughing mill ; After the first roll change in the finishing mill, the maximum speed of the horizontal rolls in the roughing mill ; From then on until the next roll change in the roughing mill, the maximum speed of the horizontal roll of the roughing mill is .

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