A method for automatically determining tail folding and automatically cutting for hot rolling

Abstract

The present invention discloses a method for automatically determining tail folding and automatically shearing in hot rolling, the method comprising: determining whether the tail pin extends into the limit position inside the steel coil according to a proximity switch; if the proximity switch determines that the tail pin extends into the limit position inside the steel coil, the tail pin retracts after the tail of the strip passes through the pinch roller, and then the flying shear shears the tail of the strip to complete the shearing; if the proximity switch determines that the tail pin fails to extend into the limit position inside the steel coil, the flying shear shears the uncoiled part of the strip, and the tail pin retracts after the uncoiled part of the strip stops moving to complete the shearing. The present invention only adds a proximity switch to the original equipment of the hot rolling mill, and the state of the tail pin extending into the steel coil is judged by the proximity switch, which can effectively avoid the occurrence of overlapping rolling of the tail of the strip and avoid double-layer strip from entering the finishing mill; it effectively protects important equipment such as working rolls and connecting shafts, reduces the probability of accidents, and ensures smooth production.

Description

Technical Field

[0001] The invention relates to the technical field of strip steel production, and in particular to a method for automatically determining tail folding and automatically shearing for hot continuous rolling. Background Art

[0002] In the hot rolling production process, the slab passes through the heating furnace and rough rolling before reaching the hot coil box. The hot coil box coils the steel coil and then unwinds it. The strip passes through the flying shear and finish rolling and reaches the down coiler.

[0003] Under normal circumstances, the hot coil box unwinds after the unwinding conditions are met, and the 2D roller and the tail roller rotate to drive the strip forward. The production control process is as follows: Figure 1 As shown in the figure, the head of the strip enters the upper and lower pinch rollers, and the gap between the upper and lower pinch rollers is immediately positioned to the thickness of the strip (the error is plus or minus 2mm). Driven by the upper and lower pinch rollers, the strip enters the finishing mill through the flying shear, and the hot coil box unwinds normally. When it is detected that the diameter of the steel coil in the hot coil box reaches the set data (the last circle), the tail pin goes deep into the coil to help open the tail of the steel coil. Under the action of the tail pin, the last circle of the steel coil is opened and enters the upper and lower pinch rollers. The tail pin retracts to the initial position, and the flying shear cuts off the irregular shape of the tail of the strip, and the tail enters the finishing mill.

[0004] During the production process, the split pin fails (or does not extend into place), and the steel coil at the top of the last circle falls due to gravity and the tension of the pinch rollers, causing the upper and lower layers of the steel coil to be squeezed by the split rollers and the upper and lower pinch rollers, resulting in the two layers stacked together. At this time, the pinch rollers are forced to squeeze apart (up and down vertical directions) without any instructions from the PLC. If the operator does not confirm, the two layers of strip steel will enter the flying shear, causing the shear blade to collapse. After entering the finishing rolling F1 mill, important equipment such as the working rolls and connecting shafts will be directly damaged. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a method for automatically determining tail folding and automatically cutting for hot rolling, comprising:

[0006] Determine whether the split pin has extended into the limit position inside the steel coil according to the proximity switch;

[0007] If the proximity switch determines that the split pin has reached the limit position inside the steel coil, the split pin will retract after the tail of the strip passes through the pinch rollers, and then the flying shear will shear the tail of the strip to complete the shearing;

[0008] If the proximity switch determines that the split pin fails to extend into the limit position inside the steel coil, the flying shear cuts the unrolled part of the strip. After the unrolled part of the strip stops moving, the split pin retracts to complete the shearing.

[0009] Furthermore, when the proximity switch fails and the gap between the pinch rollers increases abnormally,

[0010] The flying shear shears the uncoiled part of the strip, and after the uncoiled part of the strip stops moving, the tail pin retracts to complete the shearing.

[0011] Furthermore, the failure of the proximity switch is that the proximity switch always detects the limit position where the split pin extends into the interior of the steel coil.

[0012] Furthermore, the flying shear may also provide an alarm before shearing the uncoiled portion of the strip.

[0013] Furthermore, a proximity switch is installed at the action position where the split pin extends into the extreme position of the center of the steel coil.

[0014] Furthermore, the uncoiling diameter of the steel coil is less than or equal to 900 mm.

[0015] Furthermore, after the shearing is completed, the sheared strip steel stops moving and the other end of the strip steel tail enters the rolling mill.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention only adds a proximity switch to the original equipment of the hot rolling mill, and judges the state of the split pin extending into the interior of the steel coil through the proximity switch, and determines the state of the split pin extending into the interior of the steel coil according to the proximity switch. If the split pin extends into the interior of the steel coil abnormally, the flying shear is activated in time by judging the abnormality of the roller gap value of the pinch roller, which can effectively avoid the occurrence of overlapping rolling of the tail of the strip and avoid the double-layer strip from entering the finishing rolling mill; if the proximity switch fails, the flying shear shears the unrolled part of the strip, and the split pin retracts after the unrolled part of the strip stops moving, thereby effectively protecting important equipment such as the working roll and the connecting shaft, while also reducing the probability of accidents and ensuring the smooth progress of production.

[0018] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the steps or processes indicated in the description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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 creative work.

[0020] Figure 1 The flow chart of strip tail shearing under normal production control is shown;

[0021] Figure 2 A schematic cross-sectional view of the tail shearing of the strip under normal production control is shown;

[0022] Figure 3 A schematic cross-sectional view of a steel strip during rolling is shown;

[0023] Figure 4 A flow chart of a method for automatically determining tail folding and automatically cutting in hot rolling according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0024] Normal hot rolling production Figure 2 As shown in the figure, when the diameter of the steel coil in the hot coil box reaches the set data (the last circle), the tail pin goes deep into the coil to help open the tail of the steel coil. Under the action of the tail pin, the last circle of the steel coil is opened and enters the upper and lower pinch rollers. The tail pin retracts to the initial position, and the flying shear cuts off the irregular shape of the tail of the strip, and the tail enters the F1 rolling mill. During the production process, the 2D roller and the tail roller are always tangent to the steel coil, and the steel coil changes from large to small, so the position of the center of the steel coil is constantly changing. In the last circle, the tail pin must be inserted into the center of the steel coil to the extreme position to ensure that the tail does not fall due to gravity and the tension of the pinch rollers, causing overlapping rolling.

[0025] like Figure 3 As shown in the figure, if the tail pin moves abnormally or cannot be extended into the center of the steel coil to the limit position, the tail of the strip will be overlapped due to the influence of gravity and the tension of the pinch roll. The two layers of strip will enter the flying shear, causing the shear blade to collapse, and after entering the finishing rolling F1 mill, it will directly cause damage to important equipment such as the working roll and the connecting shaft.

[0026] To this end, the present invention installs a proximity switch at the limit position of the split pin extending into the center of the steel coil, and determines whether the split pin reaches the limit position of the center of the steel coil by the proximity switch. A corresponding tail shearing method is also provided when the proximity switch fails.

[0027] The present invention provides a method for automatically determining tail folding and automatically cutting for hot rolling, comprising:

[0028] Determine whether the split pin has extended into the limit position inside the steel coil according to the proximity switch;

[0029] If the proximity switch determines that the split pin has reached the limit position inside the steel coil, the split pin will retract after the tail of the strip passes through the pinch rollers, and then the flying shear will shear the tail of the strip to complete the shearing;

[0030] If the proximity switch determines that the split pin fails to extend into the limit position inside the steel coil, the flying shear cuts the unrolled part of the strip. After the unrolled part of the strip stops moving, the split pin retracts to complete the shearing.

[0031] In an embodiment of the present invention, a proximity switch is installed at the position where the split pin extends into the limit position of the center of the steel coil, and the proximity switch is used to determine whether the split pin reaches the limit position of the center of the steel coil.

[0032] In an embodiment of the present invention, when the proximity switch fails and the gap between the pinch rollers increases abnormally, the flying shear shears the unreeled portion of the strip, and after the unreeled portion of the strip stops moving, the split pin retracts to complete the shearing. The proximity switch failure means that the proximity switch has always detected the limit position of the split pin extending into the interior of the steel coil.

[0033] In an embodiment of the present invention, the uncoiling diameter of the steel coil is less than or equal to 900 mm.

[0034] In an embodiment of the present invention, the flying shear further includes an alarm reminder before shearing the uncoiled portion of the strip steel. The alarm reminder can be an alarm on the screen of the human-machine interface (HMI), or an audible and visual alarm can be made in the operating room to remind the operator that there is a problem of overlapping rolling at the tail of the strip steel.

[0035] In an embodiment of the present invention, the strip steel passes through a rolling mill after the shearing is completed. After the shearing is completed, the shearing also includes that the sheared strip steel stops moving and the other end of the strip steel tail passes through a rolling mill.

[0036] The following will be combined with the specific embodiments of the present invention and the drawings of the specification to clearly and completely describe the technical solutions 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 creative work are within the scope of protection of the present invention.

[0037] like Figure 4 As shown, in one embodiment of the present invention, taking a hot rolling mill as an example, a proximity switch is installed at the action position of the hot coil box where the tail pin extends into the extreme position of the center of the steel coil, and the method for automatically determining the tail folding and automatically cutting for hot rolling includes the following steps:

[0038] a. The head of the strip passes through the upper and lower pinch rollers, and the gap between the upper and lower pinch rollers is immediately positioned to the thickness of the strip (the error is plus or minus 2mm). Driven by the upper and lower pinch rollers, the strip passes through the flying shear and enters the finishing mill. The hot coil box unwinds normally, and the coil diameter is less than or equal to 900mm; when the coil diameter of the hot coil box reaches the set data, it indicates that the strip is about to be curled to the tail;

[0039] b. The split pin goes deep into the steel coil. According to the proximity switch, the split pin normally extends into the steel coil or abnormally extends into the steel coil. Normal or abnormal here refers to whether the split pin reaches the limit position of the center of the steel coil;

[0040] b1. If the proximity switch fails to detect abnormalities, and the split pin is always detected to be at the limit position inside the steel coil, and the gap between the pinch rollers increases abnormally, then the process goes to step cg;

[0041] b2. If the proximity switch determines that the split pin cannot be inserted into the limit position inside the steel coil, the process goes to step cg;

[0042] b3, the proximity switch determines the limit position of the split pin extending into the steel coil, then proceeds to step hj;

[0043] c. If it is determined to be tail overlap, an alarm will be given on the HMI screen and an audible and visual alarm will be given in the operation room;

[0044] d. The flying shear is started immediately to shear the rolled strip to prevent double-layer strip from entering the F1 finishing mill;

[0045] e. 2D roller, upper and lower pinch rollers, and tail roller stop working;

[0046] f. The cotter pin retracts to its initial position to complete the shearing;

[0047] g. As the 2D roller, upper and lower pinch rollers, and tail roller stop working, the sheared strip stops moving, and the other end of the strip tail is driven into the F1 finishing mill;

[0048] h. The tail of the strip passes through the upper and lower pinch rollers;

[0049] i. The cotter pin retracts to its initial position;

[0050] j. The flying shear cuts off the irregular tail of the strip and completes the shearing. Because the 2D roller, upper and lower pinch rollers, and tail opening roller stop working, the sheared strip stops moving, and the other end of the strip tail is driven into the F1 finishing mill.

[0051] In this embodiment, there are three situations. Situation 1: The proximity switch fails to detect an abnormality (the limit position of the splitter pin extending into the interior of the steel coil is always detected), and the roller gap value between the upper and lower pinch rollers is periodically scanned. Once it is found that the gap with the set value is too large, it indicates that the tail of the strip has been overlapped. Situation 2: When the proximity switch is normal, the proximity switch determines that the splitter pin fails to extend into the limit position inside the steel coil. At this time, regardless of whether the roller gap value between the upper and lower pinch rollers is normal, the tail may be at risk of overlap under the tension of the pinch rollers and its own gravity. In these two situations, the flying shear immediately cuts off the strip to prevent double-layer strip from entering the finishing mill; then the 2D rollers, upper and lower pinch rollers, and splitter rollers stop working, and the splitter pin returns to its initial position. Situation 3: The proximity switch determines that the splitter pin extends into the limit position inside the steel coil, and production can be carried out normally.

[0052] To sum up, the present invention only adds a proximity switch to the original equipment of the hot rolling mill, and judges the state of the tail pin extending into the interior of the steel coil through the proximity switch, and determines the state of the tail pin extending into the interior of the steel coil according to the proximity switch. If the tail pin abnormally extends into the interior of the steel coil, the flying shear is activated in time by judging the abnormality of the roller gap value of the clamping roller, which can effectively avoid the occurrence of overlapping rolling of the tail of the strip and avoid the double-layer strip from entering the finishing mill; if the proximity switch fails, the flying shear shears the uncoiled part of the strip, and the tail pin retracts after the uncoiled part of the strip stops moving, thereby effectively protecting important equipment such as working rolls and connecting shafts, while also reducing the probability of accidents and ensuring smooth production.

[0053] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for automatically determining tail folding and automatically cutting for hot rolling, characterized in that: include, Determine whether the split pin has extended into the limit position inside the steel coil according to the proximity switch; If the proximity switch determines that the split pin has reached the limit position inside the steel coil, the split pin will retract after the tail of the strip passes through the pinch rollers, and then the flying shear will shear the tail of the strip to complete the shearing; If the proximity switch determines that the split pin fails to extend into the limit position inside the steel coil, the flying shear cuts the unrolled part of the strip, and the split pin retracts after the unrolled part of the strip stops moving, completing the shearing; The method further includes when the proximity switch fails and the gap between the pinch rollers increases abnormally, The flying shear shears the uncoiled part of the strip, and after the uncoiled part of the strip stops moving, the tail pin retracts, completing the shearing; The failure of the proximity switch is that the proximity switch always detects the limit position where the split pin extends into the interior of the steel coil.

2. The method according to claim 1, characterized in that: The method also includes providing an alarm before the flying shear shears the uncoiled portion of the strip.

3. The method according to claim 1, characterized in that A proximity switch is installed at the point where the split pin extends into the extreme position of the center of the steel coil.

4. The method according to claim 1, characterized in that The uncoiling diameter of the steel coil is less than or equal to 900 mm.

5. The method according to claim 1, characterized in that: After the shearing is completed, the sheared steel strip stops moving and the other end of the tail of the steel strip enters the rolling mill.

Images