JPS6156714A - Grinding method of work roll in work-roll shifting mill - Google Patents

Abstract

PURPOSE:To improve rolling efficiency by providing a roll grinder pressing a grinding belt against a work roll, and grinding the taper and body parts of said roll respectively based on the prescribed conditions. CONSTITUTION:Guide shafts 10, 11 parallel to the axial centers of work roll 6, 7 are arranged, and roll grinders 12, 13 reciprocating parallel to the rolls 6, 7 are provided. Grinding belts 22, 23 for grinding the outer surfaces of rolls 6, 7 through platens 20, 21 are disposed in the grinders 12, 13. By this mechanism, when a rolling tonnage attains a prescribed quantity; a worn part produced in a roll taper-part is first ground, and the rolls 6, 7 are successively ground by the grinder 12, 13 for correcting the surface roughening of each roll body-part. Therefore, a roll-changing frequency is remarkably reduced and the rolling efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for grinding work rolls in rolling, and particularly to a method incorporating a pair of work rolls having a tapered portion at one end and reciprocating in the axial direction. The present invention relates to a method for grinding work rolls during rolling days.

BACKGROUND OF THE INVENTION At present, for example, finish rolling in a hot rolling facility, a four-layer rolling groove with grooves as shown in Fig. 4 (A>) is the mainstream. It has a structure in which a pair of columnar work rolls 1.2 are arranged vertically in parallel, and backup rolls 3.4 are respectively arranged behind them (that is, on the upper or lower side), and the rolled material 5
The rolling blade is assisted by a backup roll 3.4, and also performs a bending action via the backup roll 3.4. When rolling is performed using this type of rolling example, the O fill of the rolled material 5 is as follows:
As shown in FIG. 5(B), the entire surface becomes convex and a crown is formed. Since the crown has an adverse effect on the shape rust of the final product and the subsequent cold rolling process, it is basically preferable to correct the crown as much as possible during rolling.
For this purpose, a cross mill or a five- or six-stage HCC mill has been proposed. With these rolling mills, crown control can be carried out to some extent effectively, but since their structure is special compared to the 4-film rolling mill, major modifications of existing equipment are required to introduce them. There are disadvantages that are inevitable.

Therefore, the present applicant has proposed that crown control can be performed extremely effectively and that existing EQ
We have already proposed a rolling method using a work roll shift system that can be incorporated into a rolling method (Japanese Patent Application Laid-open No. 77903/1983). To explain the outline of this method, the work roll 6.7 has a substantially cylindrical shape W46a1 as shown in FIG. 5(A).
The work rolls 6.7 are arranged one above the other so that the tapered parts 6b and 7b face in opposite directions, and a backup roll 8.7 is provided behind each of the work rolls 6.7a. Place 9. During rolling, the edges of the rolled material 5 are adjusted to each tapered portion 6a, 7.
The work roll 6.7 is reciprocated in the axial direction in the state indicated by a. According to the method proposed by the present applicant, the contact pressure with the backup roll 8.9 on the bodies 6a, 7a of the work roll 6.7 is reduced, so that an extra bending moment is applied to the work roll. 15
1D As shown in <8>, the crown can be controlled to the right. In addition, since the sudden change in roll flattening deformation at the edge portion of the rolled material 5 can be alleviated, the peculiar metal 70- is eliminated from the edge portion, and edge drop can be effectively reduced and suppressed, and the overall shape and shape can be reduced. A strip with a good profile can be obtained.

Problems to be Solved by the Invention In the above-mentioned work roll shift rolling method, the work roll is reciprocated in the axial direction with the edge of the rolled material caught on the tapered mouth of the work roll. Areas near the boundaries tend to wear out earlier than other parts, and when the amount of wear exceeds a predetermined size, functions such as crown control and edge drop reduction cannot be performed. In such a case, conventionally, the work roll is replaced and the removed work roll is ground in a roll shop to reproduce the shape of the work roll to the shape at the initial stage of rolling.

In such a conventional method, the work rolls have to be replaced frequently (approximately 6 times/day), resulting in poor rolling efficiency and a problem that the roll schedule is severely restricted.

Means for Solving the Problem In order to solve the above-mentioned problems, the present invention provides a method for prolonging the life of a work roll having a tapered portion at one end by grinding the work roll while it is assembled on a rolling stand. The purpose is to provide the following. That is, in the method of the present invention, a pair of work rolls each having a tapered portion continuously formed on one end of a chest having a substantially cylindrical shape are arranged one above the other so that the tapered portions face in opposite left and right directions. death,
In addition, when rolling is performed by a work roll shift rolling vibration that reciprocates the work roll in the axial direction during rolling, a roll grinder that presses a grinding belt against the work roll is arranged so as to be able to reciprocate in a direction parallel to the work roll. The taper shape at the initial stage of rolling is reproduced by grinding the tapered portion with the roll grinder when the rolling is delayed to a predetermined condition after the start of rolling.
The present invention is characterized in that when a predetermined second condition is reached by further rolling, the barrel is ground-in by a roll grinder.

Real M leap Next, this invention will be explained in detail.

FIG. 1 is a schematic diagram showing an apparatus for carrying out the method of the present invention, and a pair of work rolls 6.7 are attached to one end of the cylinders 6a and 7a as shown in FIG. Each work roll 6.7 has a structure in which tapered portions 6b and 71) are continuously formed, and each work roll 6.7 is arranged vertically so that its tapered portions 6b and 7b face in opposite left and right directions, and is configured to reciprocate in the axial direction. The bottom is grooved. Also, each work roll 6.
7, that is, above the upper work roll 6 and below the lower work roll 7, there are backup rolls 8.9, respectively! ! i! It has been fi2.

Guide shafts 10.11 parallel to the axes of the rolls 6, . . . 9 are arranged above and below the rolled material 5 passing between the work rolls 6.7, and are controlled online. A roll grinder 12.13 is mounted on the guide shaft 10.11 and is reciprocated parallel to the work roll 6.7. The roll grinder 12.13 has a platen rod 1G, 17 which is retracted by a hydraulic cylinder 14.15 towards the work roll 6.7;
．． At the tip of 17, there is an elastic member 18 such as a spring.
A platen 20.21 that receives an extrusion force of 1.1 is built in, and is grooved so that the grinding belt 22.23 passing through the front side of the platen 20.21 is pressed against the outer surface of the work roll 6.7. Here grinding belt 2
2.23 is a 1ζ material in which abrasive grains are attached to a long strip-shaped base material, and the platen 20 is
．． It passes through the front side of the grinding belt 21 and is wound around the take-up reel 26.27.The feed speed of this grinding belt 22.23 is 1 to 311/mm, and its direction is the same as that of the work roll 6.7. The direction is opposite to the direction of rotation.

6, the elastic member 18, 19 and the platen rod 16,
A load cell 28.29 is arranged between the 17 and 17, and the pressing force of the grinding belt 22.23 is controlled by controlling the hydraulic cylinder 14.15 based on the output signal to adjust the traveling quality of the platen rod 16.17. 100~400k (
It is designed to be controlled by J. Although not specifically shown, the roll grinder 12.13 is connected to the guide shaft 10.
．． The driving mechanism for running along the roll grinder 11 is a chain or a fluid pressure cylinder, etc., and the running speed of the roll grinder 12.13 is 1 to 2ff! /man is set.

In plate rolling by the above-mentioned work roll shift rolling with the roll grinder 12.13 screwed in, the work roll 6.7 is rotated around its axis with the edge part of the rolled material 5 touching the tapered part 51z7b of each work roll 6.7. direction
This is done by applying Wb. Therefore, Figure 2 (A)
As shown in the figure, at the beginning of rolling i! ! ! The tapered portions 6b and 7b, which are not worn, have r?s as shown in FIG. 2(B) due to friction with the edge portions of the rolled material 5 due to continuous rolling. , pure quality will occur. The amount of wear is almost comparable to the rolling tonnage, and since the shape and profile of the product have an unavoidable limit yJ wear, the predetermined condition in this example is that the depth h of the worn part is Before reaching the limit base, that is, when the rolling m reaches a predetermined tonnage, the tapered portion 611.7b is ground to eliminate the worn portion.

FIG. 2(C) shows the tapered shape after grinding. Such grinding of the tapered portions 61+, 7b is carried out by moving the roll grinder 12, ]3 to a position corresponding to the tapered portions 6b, 7b in the gap where the rolling tonnage is a predetermined tonnage. Grind belt 22.23 with platen rod 1G, 17
Tapered portions 6b, 7 by I3 and platens 2Q, 21
b, the grinding belt 22.23 is run in the opposite direction to the direction of rotation of the work roll 6.7, and the roll grinder 12.13 is reciprocated in the axial direction of the work roll 6.7. In that case, by reciprocating the roll grinders 12 and 13, the tapered portion 6b
, 7b changes, but the pressing force of the grinding belts 22, 23 is kept constant by adjusting the protrusion and width of the platen rods 16, 17 using the output signals of the load cells 28, 29.

Further, by grinding the tapered portions 6b, 7b, the boundary with the cylinder 68.7a is shifted by a predetermined distance δ toward the cylinders 6a, 7a, so that rolling after grinding of the tapered portions 6b, 7b is performed by the work roll 6. 7 is determined in the axial direction by taking into consideration the deviation dimension δ, and is caused to reciprocate in the axial direction.

By the way, the roughness on the surface of the work roll 6.7 is not noticeable due to wear caused by friction with the edge part of the rolled material 5, so when the tapered parts 6b and 7b are ground as described above, the work The surfaces of rolls 6.7 [6a and 7a] are in a state where rolling can be continued. Therefore, after grinding the tapered portions 61) and 71) to reproduce the tapered shape at the beginning of rolling, rolling is continued.

By further rolling, a g range is generated in the tapered portions 6b, 7b due to the edge portions of the rolled material 5, but at the same time, the surface roughness of the cylinders 5a, 7a progresses.

Since the surface roughness of the cylinders 6a and 7a is also approximately proportional to the rolling tonnage, the second condition in this example is that the work rolls 6.7
Rolling tonnage after the start of use or previously performed M6
When the rolled tonnage of the cylinders 6a and 7a after grinding reaches a predetermined tonnage, the cylinders 6a and 7a are subjected to break-in grinding. That is, the roll grinder 12.13 is reciprocated several times in the axial direction of the work roll 6.7 while the grinding belt 22.23 is pressed against the surfaces of the cylinders 6a, 7a.

FIG. 3 is a block diagram showing the above-mentioned grinding procedure. That is, the number of rolling rounds is input to the central processing unit CPU by inputting the weight or dimensions of the sheet bar. On the other hand, the limit thickness 11 of the wear portion that occurs in the tapered portions 6b and 7b is about 40 μm, and such wear occurs when rolling 200 to 500 tons.
When the rolled tonnage loaded reaches a predetermined amount in the range of 200 to 500 tons, the roll grinder 12.13.
is driven to grind the tapered portions 6b and 7b as described above. In that case, the amount of grinding is 22.23
The pressing force of the grinding belt 22.23 and the work roll 6.7
Since it is determined by known controllable factors such as the relative speed difference between the grinding belt 22 and the grinding belt 22, 23, the grain size of the grinding belt 22, 23, and the time, the required grinding amount is 11itJ'XJ depending on the grinding time. That is, the roll grinder 12.13 is stopped and returned to its original state by the off signal as the predetermined grinding time elapses, and the tapered portion 6b,
Finish the grinding of 7b. Also, at this time, the product U value of the rolling tonnage for grinding the tapered portions 6b, 71) is reset to zero.

On the other hand, lN6a, 7a in work roll 6.7
Normally, the roughness of the surface reaches its limit after rolling 1000 to 1500 tons.
When it reaches a predetermined hill in the range of 01-1, the roll grinder 12.13 is driven and the ff1
Perform break-in grinding in steps 5a and 7a to correct rough skin.

Also in this case, since the amount of grinding is determined by known controllable factors, the roll grinder 12.13 is stopped and returned to its original state by the off signal as the predetermined grinding time elapses, completing the break-in grinding of 16a and 7a. do. Also e6a
, 7a, the integrated value of rolling tonnage for leveling is reset to zero.

Note that depending on the rolling type and rolling conditions, the circle 6a
, 7a may be several times the rolling tonnage or period for grinding of tapered portions 61) and 7b. In such a case, , 7a, the tapered portions 6b and 7b are ground it times. Furthermore, if the timing of grinding the cylinders 6a, 7a and the timing of grinding the tapered portions 6b, 711 match, it is of course possible to grind both at the same time according to the respective grinding conditions.

Additionally, since the profile of the rolled material 5 is generally constantly monitored by a profile meter, the local height and trunk distance of the tapered portions 6b and 7b of the work rolls 6.7 are determined based on the detection signal of the profile meter. 5a, 7a
If an abnormality in rough skin is known, in addition to controlling the grinding timing based on the rolling tonnage mentioned above, the profile making detection signal is input to the central processing unit CPU, and the taper is adjusted based on the abnormal signal from the profile meter. Part 6b,
The grinding of 7b and the grinding of cylinders 6a and γa may be repeated 11 times.

The grinding of the work roll 6.7 described above is carried out during rolling while the work roll 6.7 is attached to the rolling stand, but by repeating such grinding, the outer diameter decreases and the neck part Since maintenance is also required, the work rolls 6 and 7 are finally removed from the rolling stand and replaced with new work rolls, and the removed work rolls are subjected to processing such as grinding in a roll shop.

Effects of the Invention As is clear from the above description, according to the method of the present invention, local wear and roughness of the threads caused by rolling in the tapered portion of the work roll can be removed by grinding the work roll while it is attached to the rolling stand during rolling. Since the work rolls can be removed and corrected, the service life until the work rolls need to be replaced is significantly extended compared to 7.4, and in other words, the frequency of work roll replacements can be significantly reduced.
The efficiency of rolling operations can be significantly improved. Further, according to the method of the present invention, a roll grinder for grinding the taper part and leveling grinding of the barrel can be used online.
In such cases, constraints on roll schedules can be significantly reduced, making it easier to synchronize continuous casting and hot rolling, and reducing heating furnace consumption. It can have great practical effects.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an apparatus for carrying out the method of the present invention, and Fig. 2 (A) CB > (C) shows the process of changing the shape of the work roll near the boundary between the body and the tapered part. Fig. 3 is a block diagram that does not show the grinding procedure;
Figure (A) is a schematic diagram showing the arrangement of rolls in a four-layer rolling mill, Figure 4 (B) is a diagram showing the profile obtained by the four-layer rolling, and Figure 5<A) is a work roll shift rolling mill. FIG. 5(B) is a diagram showing the profile obtained by the rolling mill. 5... Rolled material, 6.7... Work roll, 5a
. 7a-fHl 6b, 71) -, -Tapered portion, 12.
13... Roll grinder, 22.23... Grinding belt, D... Wear part. Figure 1 Figure 2 Figure 3 Figure 4 (A) Figure 5 (A)

Claims (1)

[Claims] A pair of work rolls each having a continuous taper portion formed at one end of a substantially cylindrical body are arranged one above the other so that the taper portions face in left and right opposite directions, and the work rolls are When rolling is performed using a work roll shift rolling machine that reciprocates rolls in the axial direction, a roll grinder that presses a grinding belt against the work roll is arranged so as to be able to reciprocate in a direction parallel to the work roll. After the start, when a predetermined condition is reached, the tapered part is ground by the roll grinder to reproduce the taper shape at the initial stage of rolling, and when the rolling is further performed and a predetermined second condition is reached. A method for grinding work rolls in a work roll shift rolling mill, characterized in that the body is subjected to smoothing grinding using a roll grinder.