KR20140082559A - Mandrel of coil box - Google Patents

Abstract

According to the present invention, a mandrel of a coil box comprises: a cylindrical mandrel main body where a contral shaft is arranged inside, and having a slot into which the leading end of a high temperature bar is inserted; and a guide part arranged inside the mandrel main body from the edge wall in one side of the slot to block cooling and plastic deformation of the leading end of the bar inserted through the slot. According to the present invention, a guide part protruding toward the inside of the mandrel main body from the edge wall in one side of the slot is formed to non-contact the central shaft, when the leading end of the bar is inserted into the slot. Therefore, the cooling and plastic deformation of the leading end of the bar inserted through the slot can be blocked. Furthermore, the inserted length can be reduced. The present invention has an effect for preventing that the surface of a work roll is damaged due to a tail twist generated by the non-uniform temperature of a rolling tail part (corresponding to the leading end of a bar in mandrel coiling) when a steel sheet is rolled; and preventing the poor quality of a material due to damage in the surface of the work roll. In addition, the plastic deformation can not generated and a part contacting an edge wall in the other side of the slot can not be easily bent when the bar is wound in a mandrel by reducing the length of the leading end of the bar inserted through the slot. In other words, the leading end inserted when the bar is wound is not drooping and supporting the guide part by contacting the guide part with the proper force, so the initial inner winding of the bar about the mandrel is smoothly formed. Therefore, the present invention has the advantage of preventing that the operation is interrupted due to defect of forming an initial inner winding.

Description

The mandrel of the coil box {Mandrel of coil box}

The present invention relates to a mandrel of a coil box, which is a mandrel of a coil box, which is capable of preventing cooling of a leading end portion of a bar inserted through a slot and plastic deformation, and further shortening the inserted length.

1 is a configuration diagram of a rolling facility including a coil box according to the prior art.

1, the continuous casting process includes a ladle 5 containing refined molten steel in a steelmaking process, a tundish for temporarily storing molten steel supplied through an injection nozzle connected to the ladle 5, A mold 15 for initially solidifying the molten steel received from the tundish 10 into a predetermined shape and a mold 15 for bending or straightening the unfrozen slab at the lower portion of the mold 15, And includes a plurality of segments 20 for performing operations.

In this continuous casting process, the slabs are cooled and pressed while the slabs pass through the segments 20 and are continuously cast.

The slab that has passed through the segment 20 can be rough-rolled, cut, and heated while passing through the roughing mill 25, the cutters 30, 35, and the inductive heater 40.

In addition, the slab having been subjected to the above process is formed into a bar 1, and the bar 1 may be supplied to the coil box 100 and coiled or uncoiled.

On the other hand, when the coiling or uncoiling time of the slab is delayed in the coil box 100, the continuously fed bar 1 can be scrapped in a plate form in a process such as a cutter.

A cutter 45, a finishing mill 50, a run-out table 55, a final cutter 60 and a winder 70 are sequentially arranged at the rear of the coil box 100, The supplied bar 1 can be continuously rolled, cut, and wound into a unit coil.

The described process is an example in which the coil box according to the present invention can be applied, and the coil box of the present invention can be applied to various steel processes.

Here, the coil box 100 serves as a buffer according to the process speed in the performance and hot-rolled direct process, thereby enabling continuous operation, and will be described in more detail with reference to FIGS. 2 to 5 .

Fig. 2 is a perspective view showing a coil box in the rolling facility of Fig. 1, Fig. 3 is a perspective view showing the coil box of Fig. 2 from another angle, Fig. 4 is a plan view showing the coil box of Fig. Sectional view taken along line I-I 'of Fig.

The coil box 100 of the present embodiment can reduce the temperature and material deviation between the line and the rear end of the bar 1 by coiling the bar 1 having undergone rough rolling in the form of a coil and keeping it at a constant temperature .

The coil box 100 is provided with a draw-in unit 112 at the front, through which the bar 1 is drawn into the inside of the coil box. A leveler 116 is provided behind the coil box 100 to discharge the bar 1 to the outside of the coil box 100.

Also, the coil box 100 may be provided with a carousel 130 for coiling or uncoiling the bar 1. The carousel 130 is a device for rotating and moving the mandrel 132, and the driving unit 140 can be connected.

The carousel 130 may also be provided with a mandrel 132 and a rotating wheel 134 on which the bar 1 is wound.

Here, the mandrels 132 are provided in a pair corresponding to each other, and one of the mandrels 132, i.e., the first mandrels 132, coils the bar 1 inserted into the coil box, One is provided to uncoil and discharge the mandrel 132 ', i.e., the second mandrel 132', with the other bar 1 pre-coiled.

On the other hand, when the coiling of the bar 1 is completed in the first mandrel 132 and the uncoiling of the bar 1 of the second mandrel 132 'is completed, The first mandrel 132 and the second mandrel 132 'can be changed in position by rotating the rotating wheel 134 through the first mandrel 132 and the second mandrel 132. [ The first mandrel 132 with the bar 1 coiled thereby uncoiling the bar 1 and the new mandrel 132 'with the bar 1 uncoiled is inserted into the new The bar 1 is coiled.

As such, the carousel 130 can be moved to position the first mandrel 132 and the second mandrel 132 'so that the coiling and uncoiling of the bar 1 is reversed, can do.

The first mandrel 132 and the second mandrel 132 'may be connected to a motor 136 for applying a rotational force to the first mandrel 132 and a speed reducer 138 for adjusting the rotational speed of the motor 136, have.

In the coil box 100 constructed as described above, the bar 1 is referred to as a mandrel 132 (hereinafter, the first mandrel 132 or the second mandrel 132 'is referred to as a mandrel 132) It is necessary to ensure the control precision of tracking of the length of the leading end of the bar 1 inserted into the mandrel 132 so that the continuous operation due to the failure of coiling is not interrupted.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method and apparatus for preventing the cooling and plastic deformation of the distal end portion of a bar inserted through a slot, And a guide portion protruding from the one side wall of the slot to the inside of the mandrel main body so as not to be contacted.

In order to achieve the above object, a mandrel of a coil box according to a preferred embodiment of the present invention includes: a cylindrical mandrel body having a central axis disposed therein and a slot into which a tip of a hot bar is inserted; And a guiding portion disposed inside the mandrel body from one side wall of the slot to block cooling and plastic deformation of the leading end of the bar inserted through the slot.

Here, it is preferable that the guide portion protrudes from one side edge wall of the slot so that the leading end of the bar is not in contact with the central axis when inserted into the slot.

At this time, it is preferable that the end portion of the guide portion has a distance of 90 mm to 110 mm from the inner edge of the other side wall of the slot.

Preferably, the guide portion is inclined so that the inner gap of the slot is narrower than the outer gap.

At this time, it is preferable that the outer end of the guide portion has a distance of 200 mm to 300 mm from the outer end of the other side wall of the slot.

In addition, it is preferable that the guide portion is integrated with the mandrel main body and extends from the one side wall of the slot to the inside of the mandrel main body.

In addition, it is preferable that the guide portion is tapered from the wall of one side of the slot to the inside of the mandrel body.

In addition, in the present invention, a counterweight may be formed on the side of the mandrel main body opposite to the guide portion so as to prevent the center of gravity of the mandrel from being positioned on the guide portion side.

The mandrel of the coil box according to the present invention is constituted by a guide portion protruding from the one side wall of the slot to the inside of the mandrel main body so that the leading end of the bar is not in contact with the central axis when inserted into the slot, It is possible to prevent tip cooling and plastic deformation and further shorten the inserted length.

This prevents damage to the work roll surface due to tail twisting caused by uneven temperature in the rolling tail portion (corresponding to the tip portion of the bar during mandrel coiling) when rolling the material, It is possible to prevent defects.

In addition, since the length of the leading end of the bar inserted through the slot is shortened, the portion contacting the other edge wall of the slot can be easily bent and plastic deformation can be prevented from occurring when the bar is wound around the mandrel. That is, since the leading end portion of the bar inserted at the time of winding the bar is not sagged but is held in contact with the guide portion with an appropriate force, the bar is smoothly formed with respect to the mandrel, .

1 is a configuration diagram of a rolling facility including a coil box according to the prior art.
2 is a perspective view showing a coil box in the rolling facility of FIG.
3 is a perspective view showing the coil box of FIG. 2 from another angle; FIG.
Fig. 4 is a plan view showing the coil box of Fig. 2. Fig.
5 is a cross-sectional view taken along a line I-I 'in Fig.
6 is a view showing that a bar tip is inserted and wound in a slot in a mandrel according to the related art.
7 is a view illustrating that a bar tip is inserted and wound in a slot in a mandrel of a coil box according to an embodiment of the present invention.

First, a bar end is inserted into a slot in a mandrel according to the related art prior to the improvement, and is wound, will be described with reference to FIG.

6 is a view showing that a bar tip is inserted and wound in a slot in a mandrel according to the related art.

Referring to the drawing, in order to wind a hot bar 1 having a thickness of 16 mm to 23 mm on a mandrel 132, the tip portion 1a of the bar 1 is inserted into a mandrel 132 through a slot 132a The tip end portion 1a of the bar 1 is supported on the center shaft 133 of the mandrel 132 and the mandrel 132 is rotated by the rotational force of the mandrel 132 And is wound around the other side wall 132c of the slot 132a to form an initial lining by contacting the outer peripheral surface of the mandrel 132 while being bent.

Here, inside the mandrel 132 is a central shaft 133 for supporting the mandrel 132 in a high temperature (1,100 ° C) coil box. The center shaft 133 is designed to have a structure in which cooling water is allowed to pass therethrough .

The temperature of the central shaft 133 is about 650 ° C due to the influence of the cooling water flowing inside the central shaft 133, and the temperature of the central shaft 133 is set to be within the mandrel 132 (About 800 mm to 1,000 mm) 1a of the bar 1 which is inserted into the center shaft 133 and comes into contact with the center shaft 133 can not avoid the temperature drop.

In addition, the temperature drop portion is rolled below the Ar3 transformation point during finishing rolling, which causes not only material failure due to unstructured material but also unevenness of the rolling tail portion during rolling of the material, Causing damage to the roll surface, resulting in poor quality, and, in severe cases, causing an accident such as roll breakage. At this time, the rolling tail portion is a tail portion when uncoiling as the tip portion 1a of the coiled bar 1.

As a result, in order to satisfy the material properties of the hot-rolled steel sheet, it is important to ensure a uniform rolling temperature of the Finishing Mill Delivery Temperature of the finishing mill at the Ar3 transformation point (870 ° C) Do.

However, due to the structural problem of the mandrel 132 shape in which the incoming temperature at the finishing mill (FM) coils up the bar (1) coils, the tail of the bar (1) The temperature at the exit side of the finishing mill is lower than 800 DEG C, which results in failure to satisfy the material properties of the hot-rolled steel sheet.

In order to prevent such material defective products from being shipped to customers, there is a problem that the defective portion is removed and the process error rate falls as the product is packaged and supplied.

Specific examples of the above-mentioned temperature drop are shown in Table 1 below.

division standard The sampling position (top portion) Elongation range FDT (minimum) HS5282601 JS-SPHC 0m 5m 10m 15m 20m Lower limit maximum
822 ° C


Analysis
(3,1t) TS 408 418 393 401 391 270 - FC 322 321 290 291 279 - EL 24 25 30 34 34 27 -

[Sampling position and material test result]

* FDT: Finishing Mill Delivery Temperature (temperature of the bar after rolling)

The above table was obtained by collecting coil samples at intervals of 5 m at a temperature drop corresponding to the tail (corresponding to the tip of the bar at the time of mandrel coiling) of the bar (1) in the correcting line, This is the case where material failure occurs due to deviation from the elongation lower limit target value.

[Organization analysis result by sample position]

As a result of analyzing the tissue by position with the sampled samples, mixed texture was observed up to about 20m. Therefore, conventionally, unless the tip 1a of the bar 1 inserted into the mandrel 132 (about 800 mm to 1,000 mm) is cut, the material is defective. Therefore, before the specimen is taken, The area should be removed sufficiently.

As a result, not only the work load of the intermediate inspection and correction worker is increased but also it is impossible to avoid the inconvenience that the rough rolling process which is not required to go through further and the reduction of the correction error rate due to the cutting of the defective portion.

In order to wind the bar 1 with the mandrel 132, the tip portion 1a of the bar 1 is inserted through the slot 132a formed in the mandrel 132, The bending stress is applied to the bar 1 by the rotational force of the mandrel 132 by being supported by the shaft 133 and the other side wall 312 of the slot 132a.

In this case, since the rotational effect of the force acting on the bar 1 is determined not by the force but by the distance between the rotation axis and the point of action of the force, the torque can be expressed as Torque = force (F) x length (L). The bar 1 can be easily bent with a small force as the distance from the point of action of the force becomes longer so that the bar 1 is easily bent and plastic deformation occurs, And the other side wall 312 of the slot 132a is deformed and the force can not be balanced.

In the worst case, the operation interruption due to the defective formation of the initial internal resistance occurs frequently due to the occurrence of the deflection phenomenon, and it is necessary to improve the mandrel shape in order to overcome this.

The mandrel of the inventive coil box will now be described with reference to FIG. 7 in comparison with the mandrel of the conventional coil box shown in FIG.

7 is a view illustrating that a bar tip is inserted and wound in a slot in a mandrel of a coil box according to an embodiment of the present invention.

The present invention includes a mandrel main body 310 formed with a slot 310c and a guide portion 320 formed on one side wall 311 of the slot 310c in the mandrel main body 310 do.

The mandrel main body 310 has a central axis 200 disposed therein and a slot 310c into which the tip portion 1a of the high-temperature bar 1 is inserted. At this time, the central axis 200 maintains a state of relatively lower temperature than the hot bar 1 as the cooling water flows inside.

The guide portion 320 may be formed to extend from one side wall 311 of the slot 310c to the mandrel main body 311 to prevent cooling and plastic deformation of the tip portion 1a of the bar 1 inserted through the slot 310c. (310).

The guide part 320 protrudes from one side edge wall 311 of the slot 310c so as not to contact the center axis 200 when the tip part 1a of the bar 1 is inserted into the slot 310c, ) It is good.

As a result, the tip 1a of the bar 1 is not brought into contact with the central axis 200 having a low temperature at the time of inserting, so that the temperature does not drop below the proper temperature.

As a result, it is possible to prevent the surface of the work roll from being damaged due to twisting of the tail caused by temperature irregularity during rolling of the article (corresponding to the tip of the mandrel coiling time) Defects can also be prevented.

The length of the leading end 1a of the bar 1 inserted through the slot 310c is reduced to about 400 mm to 500 mm farther than the conventional length of about 800 mm to 1000 mm to wind the bar 1 around the mandrel 300 The portion contacting the other side wall 312 of the slot 310c is not easily bent and plastic deformation does not occur.

That is, the tip 1a of the bar 1 inserted at the time of winding the bar 1 is held in contact with the guide portion 320 with proper force without being sagged, As the formation of the internal rights is smooth, it is possible to prevent the interruption of the operation due to the initial formation of the internal rights.

The end of the guide part 320 may be spaced from the inner end of the other side wall 312 of the guide part 320 by 90 to 110 mm. The distal end portion 1a of the bar 1 can be brought into contact with the central axis 200 when inserted into the slot 310c as described above and the bar 1 can be wound around the mandrel 300 The portion in contact with the other side wall 312 of the slot 310c may not be easily bent and plastic deformation may not occur.

It is further preferable that the guide portion 320 is inclined so that the inner gap of the slot 310c becomes narrower than the outer gap.

That is, since the outer gap of the slot 310c is formed to be larger than the inner gap, it is possible to easily insert the bar 1 when the bar 1 is inserted into the slot 310c, It can serve as an insertion guide for the user.

The guide portion 320 is disposed inside the mandrel main body 310 to narrow the inner gap so that the distal end portion 1a of the inserted bar 1 is not in contact with the central axis 200 It is possible to implement more surely.

As an example, the outer end of the guide part 320 has a distance of 200 mm to 300 mm from the outer end of the other side wall 312 of the slot 310c, thereby realizing the above-described insertion guide more effectively.

The guide part 320 may be integral with the mandrel main body 310 and may extend from the one side wall 311 of the slot 310c to the inside of the mandrel main body 310.

The temperature of the distal end portion 1a of the inserted bar 1 may be lowered as the distal end portion 1a of the inserted bar 1 is disposed inside the mandrel main body 310 and approaches the central axis 200 side. So that the tip portion 1a of the bar 1 which is in contact with the guide portion 320 at the inside of the mandrel main body 310 can maintain an appropriate temperature or higher.

That is, the tip portion 1a of the bar 1 conveys heat through the mandrel main body 310 and the guide portion 320, which are integrated from the high-temperature bar 1 surrounding the mandrel main body 310, It is possible to maintain a high temperature state.

As a preferred example, the guide part 320 may protrude from one side edge wall 311 of the slot 310c to the inside of the mandrel main body 310 while tapering. Thereby making it possible to avoid contact with the center axis 200 while transmitting more heat at a higher temperature through a large area as described above.

In addition, the counterweight 330 may be formed on the side of the mandrel main body 310 opposite to the guide part 320 so as to prevent the center of gravity from being positioned on the guide part 320 side.

As shown in the figure, the counterweight 330 has a plurality of protrusions protruding inwardly from the mandrel body 310, but the present invention is not limited thereto, and the counterweight 330 may have a weight capable of offsetting the weight of the guide portion 320 Of course, can take any shape.

(Finishing Mill Delivering Temperature (FDT)) after the front end portion 1a of the bar 1 inserted into the mandrel 300 is rolled in the finish rolling as a result of the application of the present invention having the above- Which is different from the prior art. At this time, the x-axis represents the length of the bar 1, the y-axis represents the temperature (占 폚), FDT (before improvement) is the prior art prior to improvement, and FDT (after improvement) represents the present invention after improvement.

[Temperature profile of bar after rolling]

As can be seen from the above graph, the tip temperature of the bar after the improvement was about 40 ° C to 50 ° C higher than before the improvement, and the temperature of one or two inner windings contacting the outer peripheral surface of the mandrel body 310 was also about 10 ℃ ~ 20 ℃ has been increased so that it can contribute to the stabilization of the finish rolling.

In addition, this makes it possible to reduce the labor of the rough rolling and the workload of the worker for the intermediate inspection and correction for inspection of the material failure due to the drop in the temperature of the bar edge, and further to avoid a reduction in the correction error rate It was possible.

Meanwhile, numerical values of materials such as bar thicknesses provided throughout the specification of the present invention are provided by way of example, and needless to say that the present invention is not limited thereto.

As described above, according to the present invention, it is possible to reduce the insertion length of the bar 1 into the mandrel 300 and to improve the rolling conveyance due to the temperature rise of the inner peripheral portion of the bar 1 with respect to the outer peripheral surface of the mandrel 300 Even if the productivity improvement effect due to the sexual effect is not taken into consideration, the correction error rate due to the reduction of the scrap processing amount can be improved, and the improvement effect of reducing the out-of-order amount through the zero test rejection rate and the retest rejection rate is achieved.

In addition, since the hot finish material is cut in the rough rolling line in order to cut the leading end portion 1a of the bar 1, the problem that the correction processing cost is increased is improved, and a great cost reduction effect can be obtained.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood that various changes and modifications may be made without departing from the scope of the appended claims.

1: bar 1a: tip
200: central axis 300: mandrel
310: Mandrel main body 310c: Slot
311: one side wall 312: the other side wall
320: guide portion 330: counterweight

Claims (8)

A cylindrical mandrel main body 310 having a central axis 200 disposed therein and having a slot 310c into which the tip portion 1a of the hot bar 1 is inserted; And
Is disposed inside the mandrel main body 310 from one side edge wall 311 of the slot 310c to prevent cooling and plastic deformation of the leading end portion 1a of the bar 1 inserted through the slot 310c (320);
(300) of the coil box.
The method according to claim 1,
The guide part 320 protrudes from one side edge wall 311 of the slot 310c so as not to contact the center axis 200 when the tip part 1a of the bar 1 is inserted into the slot 310c (300). ≪ / RTI >
3. The method of claim 2,
Wherein an inner end of the guide part 320 is spaced apart from an inner end of the other side wall 312 of the slot 310c by 90 to 110 mm.
3. The method of claim 2,
Wherein the guide portion (320) is inclined so that an inner gap of the slot (310c) becomes narrower than an outer gap.
5. The method of claim 4,
Wherein an outer end of the guide part 320 is spaced 200 mm to 300 mm apart from an outer end of the other side wall 312 of the slot 310c.
6. The method according to any one of claims 1 to 5,
The guide part 320 is integral with the mandrel main body 310 and extends from the one side wall 311 of the slot 310c to the inside of the mandrel main body 310. [ (300).
6. The method according to any one of claims 1 to 5,
The guide part 320 is protruded from the one side wall 311 of the slot 310c while tapering toward the inside of the mandrel body 310.
6. The method according to any one of claims 1 to 5,
A counterweight 330 is provided on the side of the mandrel main body 310 opposite to the guide part 320 to prevent the center of gravity of the mandrel from being positioned on the guide part 320 side. The mandrel 300 of the coil box.

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