JP2002160008A - Hot Rolling Mill Delivery Guide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a delivery guide apron behind a finish hot-rolling mill which improves strip travel performance and lengthens a life. SOLUTION: The height of the top face of the apron is made 20 mm or less below the table pass line and/or the apron body, or its surface layer in contact with the strip is a carbon-base material, so as to improve the strip travel performance and lengthen the life.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can improve the running performance of a strip (steel plate) and maintain the running performance securing function in a run-out table from a finishing mill to a winding machine in a continuous hot steel sheet rolling facility. This is related to a hot rolling mill delivery guide.

[0002]

2. Description of the Related Art In the production of a thin hot-rolled steel sheet having a large surface area and easily causing a temperature drop, it is necessary to reduce the heat release from a roll in a finishing mill in order to secure a predetermined plate temperature on the finishing side. Therefore, it is necessary to increase the finish rolling speed. However, since the free end that is not tensioned runs on the run-out table during the leading-end threading until the leading end of the plate winds around the winder, the bending rigidity is weak, especially in a thin-sized steel plate, and air from the front is required. A phenomenon called flying, in which the tip portion floats due to the pressure, occurs. Also, the steel plate dropped between the table rollers is greatly bent due to the centrifugal force caused by the traveling speed,
A phenomenon called waving that floats greatly when the vehicle gets over the roll also occurs. For this reason, there has been a problem that the tip speed is regulated in thin rolling, which originally requires a high threading speed.

On the other hand, in the process of transferring from the rolling roll to the table roller at the exit side of the final stand of the hot rolling, particularly the finishing mill, the roll roll box generally occupies the roll end face immediately after the rolling roll, so that the transport roll Can be arranged, a delivery guide that can be retracted when changing rolls is arranged, and a resin material made by curing asbestos or glass fiber with a substrate resin is widely used as apron in the passing plate part .

[0004]

However, this resin-based material has a problem in that it has a problem in durability at high temperatures, and the contact wear with a steel sheet is apt to progress, so that there is a problem that maintenance cost is high because of frequent replacement. In addition, this resin-based material has a problem that scales dropped from the strip are apt to adhere to the resin-based material, which causes a back surface flaw and scale pattern due to contact of the strip with the apron due to a strip generated wave (waving) during traveling. In order to avoid this problem, the setting height of the apron must be set at a position lower than the transfer table pass level and generally more than 20 mm. In addition to this, abrasion of the apron material in the rolling operation is added, and the pass line is further increased. It will be retreated downward. For this reason, when the height difference from the transport rolls is remarkable, it may reach as large as 40 mm, and when the strip tip contacts the first transport roll, the collision angle becomes extremely large, and the strip tip moves upward. There is a problem that it induces a flying phenomenon and the like.
The present invention is intended to solve such a problem, and suppresses the flying phenomenon at the tip of the strip, which has conventionally occurred, improves the running property of the strip, and uses a material with a low degree of wear in the main part of the guide. An object of the present invention is to provide a hot-rolled mill delivery guide that contributes to maintaining a running performance securing function by using the same.

[0005]

The hot-rolled mill delivery guide according to the present invention is characterized in that (1) the height of the upper surface of the apron below the mill delivery guide pass line is set within 20 mm below the table pass line. . Furthermore, (2)
An apron having a carbon-based material at the surface layer in contact with the apron body and / or the strip is at least one widthwise.
It is characterized in that more than one mill delivery guide is arranged. Furthermore, (3) the surface layer portion which comes into contact with the apron body and / or the strip is made of a carbon-based material, and the installation height is set such that the upper surface height is 20 mm below the table pass line.
And at least one or more aprons are arranged in the delivery guide.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. First, a problem at the time of the conventional strip conveyance will be briefly described. When the strip tip is transported at high speed,
As shown in FIG. 2, first, a phenomenon called tip flying occurs. This is because the leading end of the strip 7 comes into contact with the transport roll 2 and an angle of attack is generated at the leading end of the strip due to the contact repulsive force. This angle of attack causes a balance between the repulsive inertial force, the rigidity of the strip, and the air fluid force. It is. In particular, this is a problem in the case of a thin high-speed passing plate in which the rigidity of the strip is weak and the air fluid force is large.

One means for addressing the above problem is the height regulation of the delivery guide apron at the apron between the transport rolls, particularly at the connecting portion from the final rolling roll to the transport roll. That is, in the tip flying, the contact angle to the roll is made small, so that the upward repulsive force is reduced, so that the amount of the tip flying can be reduced. When this behavior was analyzed by unsteady numerical calculation, as shown in FIG. 3, the strip flying amount fluctuated greatly depending on the height of the delivery apron path.
It can be seen that in order to secure the target of about 750 mm at 0 mpm or more and suppress the flying height to within 1 m, the contact height of the steel plate must be within 10 mm. Immediately after the finishing mill, an over-guide is generally installed. The floating amount of 1 m is not a direct restriction because the floating of the strip is held down by this guide, but the floating amount is limited in order to suppress plate deformation such as reverse warpage due to contact with the guide. Since the height of the conventional apron is more than 20 mm from the height of the table path, the target value is set to 20 mm or less.

In order to maintain the height of the apron, that is, to avoid abrasion of the apron material and to prevent the occurrence of scratches on the strip, tests were conducted on various materials including conventional resin materials. In the test evaluation, first search for a material that does not cause damage to the strip itself and that does not damage the strip, and a material with a low coefficient of friction to minimize stripping performance and minimize scale adhesion. That is. The test materials used were conventional resin-based materials and cast iron (equivalent to FCD600), which had been widely used before, for comparison purposes, and two types of fine ceramics (high and medium hardness) and carbon-based were proposed as new material candidates. Three types of materials (isotropic carbon, CC composite, metal impregnated). Table 1 shows the characteristics of these test materials.

[0009]

[Table 1]

The material comparison test uses a rolling test machine capable of reducing the relative speed difference between the apron and the strip conveyed at a high speed, considering that the difference in the high speed relative speed, that is, the kinetic energy greatly affects the interface. went. The test material and the iron counterpart corresponding to the running strip were formed into a disk shape, the counterpart was heated, the two were rotated relative to each other, and a contact pressure was applied for a certain period of time to perform a test. In addition, the test piece rotation drive shaft is equipped with a strain gauge, and has a structure capable of measuring a non-drive torque due to relative sliding with a counterpart, thereby measuring a relative friction coefficient. FIG. 4 shows the concept of the rolling test. In FIG. 4, 8 is a test piece, 9 is the test piece 8
Is an induction heating coil for heating the opposing piece 9, 11 is cooling water for cooling the test piece, and 12 is a radiation thermometer.

The results of the rolling test will be described. FIG. 5 shows the result of wear of the test piece. Conventionally, the wear of the resin material is the largest and by far the largest, followed by the carbon material, cast iron, and ceramics. On the other hand, looking at the amount of shaving of the opposing piece (the shaving depth of one diameter) in FIG. However, the large amount of chipping of the metal-impregnated carbon is caused by the occurrence of seizure in the metal contact. By the way, in the case of the resin-based material, the glass fiber of the base material bites into the heating piece, and the carbonized resin penetrates into the heating piece. This phenomenon and the scale adhesion due to the large friction coefficient are considered to be one of the causes of the back surface flaws and scale pattern rarely generated in the past when the pass level was increased in the past in the resin material apron. The coefficient of friction is compared with that of FIG. 7, and the values of ceramics and cast iron show large values, and the values of the resin system are also quite large. It was the carbon-based material group that showed the best value, that is, the small coefficient of friction.

[0012]

EXAMPLES Based on the above results, it can be seen that carbon-based materials, particularly isotropic carbon and CC composite materials, have excellent results. In practice, it is considered that the CC composite material, which is superior in toughness and strength, is more preferable. Therefore, a trial production of the delivery apron 5 on the structural portion (the apron surface portion in contact with the strip) shown by the thick solid line in FIG. And pass line L to delivery guide 4 of the actual hot rolling line
At a height of 10 mm (h) below, and an actual rolling test was performed. The apron portion to which this carbon-based material is applied may be only the apron surface portion in contact with the strip, or may be the apron body. In FIG. 1, reference numeral 1 denotes a work roll of a finish rolling mill, 2 denotes a transport roll constituting a roller table disposed on the exit side of the rolling mill, 3 denotes an upper wiper, and 6 denotes a retracting direction of the delivery guide 4.

As a result, the running performance of the strip has been greatly improved, since the amount of tip flying with thin material which has conventionally occurred in the zone has been reduced by about half. In addition, although the degree of wear of the conventional resin material was about one month, the wear control standard value was 7 mm or more, the CC composite material hardly changed, and its running performance improvement function could be maintained. Turned out to be. Of course, no flaw or scale pattern was generated on the back surface of the strip. Further, a similar apron may be used between the run-out table rollers from the viewpoint of ensuring the strip running property.

[0014]

According to the hot rolling mill delivery guide according to the present invention described above, the flying phenomenon at the tip of the strip, which has conventionally occurred, can be suppressed, and the running property of the strip can be improved. In addition, the use of a material having a low degree of wear for the main part of the guide is also effective in maintaining the traveling performance securing function.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a delivery guide apron of the present invention.

FIG. 2 is an explanatory diagram of a tip flying phenomenon.

FIG. 3 is a diagram showing a relationship between a roll contact position and a tip floating amount.

FIG. 4 is a conceptual diagram of a new material search rolling test.

FIG. 5 is a rolling test result graph.

FIG. 6 is a rolling test result graph.

FIG. 7 is a rolling test result graph.

[Explanation of symbols]

Reference Signs List 1 work roll 2 transport roll 3 upper wiper 4 delivery guide 5 delivery guide apron 6 guide retraction direction 7 strip 8 test piece 9 partner piece 10 induction heating coil 11 cooling water 12 radiation thermometer

Claims (3)

[Claims] 1. A hot rolled mill delivery guide, wherein the height of the upper surface of the apron below the mill delivery guide hasline is within 20 mm below the table pass line. 2. A hot rolled mill delivery guide, wherein at least one or more aprons having a carbon-based material as a surface layer in contact with the apron body and / or the strip are arranged in the mill delivery guide at least in the width direction. 3. The apron body and / or a surface layer that comes into contact with the strip is made of a carbon-based material, and the height of the installation is set within 20 mm below the table path line, and at least one of the aprons is used as a delivery guide. A hot-rolled mill delivery guide that is arranged.