JPS5861905A - Method and device for using reduction roll - Google Patents

Abstract

PURPOSE:To prolong the period for changing of rolls and to improve the operating efficiency of rolling mills, by making a pair of rolls of either of rolls which are movable in an axial direction and rolls which revolve in contact therewith changeable between the right and left. CONSTITUTION:Rolls are made to have the shapes and sizes which are symmetrical on the right and left so that their work sides can be changed with the driving sides. A radial bearing 21 and a thrust bearing 23 are disposed in a DS bearing box 19, and only the radial bearing 22 is disposed in a WS bearing box 20. Thrust load is received by only the box 19 but the shapes of the rolls are made symmetrical on the right and left. The shapes of the roll shaft ends are also made symmetrical on the right and left so as to be connected to couplings. In the case of backup rolls, the shapes of the roll shaft ends are simply required to comply with those of a changer. In the case of the rolls which are movable in an axial direction, the shoulder part on one side is required to be chamfered and the purpose is achieved by providing chamfers 25, 26 on both sides.

Description

[Detailed description of the invention] In a multi-plate rolling mill in which at least one pair of rolls can be moved in the axial direction of the rolls, the recombination cycle of the rolling rolls is extended, and the amount of rework can be reduced to one stroke. Regarding technology.

As a multi-high rolling mill capable of moving at least one pair of rolls in the roll axis direction, there are various types of rolling mills as shown in FIG. 1, for example. (a) is a 6-high rolling mill with an intermediate roll shift method, (b) is a 4-high rolling mill with a work roll shift method, (C) is a 4-high rolling mill with a reinforcing roll shift method, and (d) is a 4-high rolling mill with a sleeve shift method. It is a 6-high rolling mill.

Thus, in the present invention, the multi-high rolling mill refers to a rolling mill with four or more stages having at least one pair of reinforcing rolls, and (
, i) The sleeve which receives the rolling load as shown in the figure shall also be regarded as a roll.

These rolling mills: Mainly aimed at significantly improving the crown shape control ability, they have a structure that allows roll shifting, but due to machine design constraints, the shifting direction is changed from symmetrical to only one direction. In most cases.

However, when carrying out such a l o -le shift,
For example, the loads applied to the reinforcing roll 1, intermediate roll 2, and work roll 3 in the upper half of the six-high rolling mill shown in FIG. 1(a) are as shown in FIG. 2.

In the figure, A indicates the drive side and B indicates the work side. In other words, when the intermediate roll is shifted to the operating side (WS), the contact area between the work roll and the intermediate roll and between the intermediate roll and the reinforcing roll is The load distribution 11 between the work rolls and the material is generally symmetrical with respect to the mill center 12, so the contact load between the rolls is as shown in Figure 2 due to moment balance. The drive mll (D S > becomes larger).

This tendency may be reversed if the rolled material is shifted from the mill center 12 to the WS, but it remains unchanged except for such exceptions. However, if the operation continues under these conditions, each roll will suffer severe fatigue damage that would be unbearable in a rolling mill that does not conduct roll shifting, and the recombination cycle will be shortened and roll reformation will be required. This results in an unfavorable situation where the amount of cutting increases.

Unexploded 1 advantageously solves the drawbacks of such conventional methods and
When rolling a metal plate using a rolling mill in which at least one pair of rolls is movable in the axial direction,
At least one pair of the axially movable roll and the roll that rotates in contact with the axially movable roll is used by switching the driving side and the working side of each roll when used up to that point. The first invention is a method of using a roll in plate rolling. In addition, when rolling a metal plate using a rolling mill in which at least one pair of rolls is movable in the axial direction, at least one pair of the rolls that are movable in the axial direction and a roll that rotates in contact with the rolls are A second invention provides a method of using a roll in sheet rolling, characterized in that the upper side and the -F side of the metal sheet passing line are used interchangeably. Further, in a pressure IA machine in which at least one pair of rolls is configured to be movable in the axial direction, coupling means for the axial displacement drive means are provided at both axial ends thereof. A pair of rolls movable in the axial direction and a pair of work rolls having coupling means to a rotational drive source at both ends in the axial direction are provided with one or both of them, so that the working side and the driving side of the rolls can be interchanged and installed. A rolling mill constituted by the present invention is a third invention. Further, in a rolling mill configured to move at least one pair of rolls in an axial direction, the rolling mill has shoulder drop portions on both sides 11i11 in the axial direction, and is movable in the axial direction.
A fourth invention provides a rolling mill which is provided with rolls χ·t and configured so that the upper and lower sides of the sheet passing line can be replaced and installed.

The present invention will now be described in detail with reference to the accompanying drawings.

Transfer fatigue due to contact stress between rolls steadily progresses as long as non-linear use is continued, and eventually surface damage called spalling occurs. To prevent such accidents, the rolling rolls are periodically rearranged and the surfaces are ground to remove the hard layers.

Attempts to mechanically suppress such fatigue damage,
, ■, Already used by Shio; "Reinforced roll goods for 4-layer rolling rock
"A Consideration Regarding the Decision to Emphasize M tE M" (Japanese TV Review 1)
0150, Na6 (1968) P72-5). This is based on the assumption that the force governing the roll transfer fatigue is determined by the mechanical stress, and the resulting fatigue damage is
The fatigue damage in the radial direction of the roll was determined as progressing based on the law of linear damage of nθr, and the relationship between this and the amount of surface removal was discussed.

Based on almost the same idea, the present inventors tracked the fatigue damage accumulated on the rolling rolls of a roll-shiftable rolling mill as shown in Fig. 1, not only in the radial direction but also in the longitudinal direction. We created a simulation program that could do this and performed calculations under actual operating conditions. FIGS. 3 and 4 show an example of the fatigue damage distribution in the trunk length direction obtained as a result.

The rolling mill targeted for calculation is a 6-high rolling mill with an intermediate roll shift system shown in FIG. 1(a), and the calculation conditions are equivalent to the No. 4 stand of a hot strip mill finishing mill. The figure shows an intermediate roll (figure a) and a reinforcing roll (figure b).
The calculation is shown below, but in one recombination cycle, the intermediate roll has a rolling number of 50.
1,800,000 times, and the reinforcing roll is 1,800,000 times. Calculations for the work roll were also performed at the same time, but were omitted because the fatigue damage distribution in the longitudinal direction of the body is very similar to that of the reinforcing roll. Further, the intermediate roll shift condition is calculated as 81 degrees based on δ-0, that is, the condition that the intermediate roll body end and plate end positions are made to match.

The degree of fatigue damage F of the I slave axis is a parameter that means that fatigue failure occurs when F=1 in the so-called M i n e r number.

Figure 3 shows the fatigue damage of the upper roll in Figure 1 (a), and the loss distribution 13 when a new roll is used once is that for the middle roll, the DS body end is at the maximum +la: And it becomes smaller as it goes to WS. In the case of reinforcing rolls, the plate width of the rolling mill (g2a) is discarded and the intermediate roll shifts, so the DS reaches a certain range or peaks.
The damage to the WS is considerably smaller. This is the ftj field surface distribution 14 that still remains after such a damaged roll was reassembled and the surface modified, and this roll was assembled in the same place and the pressure under the same conditions was applied again. The subsequent fatigue damage distribution is 16. In this method, the same rolls are installed at the same position on the turn 11-roll.

Since fatigue damage accumulates only on one side of the roll, the amount of grinding required for one recombination and the amount of roll grinding is unavoidable.

On the other hand, Figure 4 shows calculation results when the upper and lower sides of the intermediate roll and reinforcing roll are replaced each time according to the present invention.The damage distribution 13 after using one new roll is shown. , up to the point where the metal loss distribution 14 is achieved by grinding is the same as in Figure 3, but it is crucial that the peak of fatigue damage 15 sustained in the next use is on the opposite side from the peak of the damage distribution of the first use. The difference is the role I'm thinking of now.

In the second rolling, the lower roll in Fig. 1(a) is used, so it is likely to be significantly damaged by the WS.Therefore, in the case of Fig. 3, the fatigue damage distribution concentrated on the DS is In Figure 4, it will also be distributed to dWs,
Compared to the conventional method as shown in FIG. 3, the recombination cycle can be made longer, and the amount of roll grinding can be significantly reduced.

In the case of the calculation examples shown in Figures 3 and 4, when comparing the peak values of the simple and dual fatigue damage distributions 16, there is a difference of about 20 inches, but in the case of Figure 4, the fatigue damage caused by the primary Considering that the maximum value of is DS, it is appropriate to use DS Loss Island as a comparison target, and in this case, the loss is reduced by about 35%.

By the way, just by looking at Figures 3 and 4, fatigue damage steadily accumulates as the number of rolling increases, and eventually F>
It may seem that the value is 1, but the disappearance is not the case.As the rolling and grinding processes are repeated, the fatigue damage level will reach a nearly constant value. This can be easily understood by considering the fatigue damage distribution in the radial direction.

FIG. 5 shows the damage distribution in the radial direction as a result of fT of the same simulation as in FIG. 3. Fifth
Figure (a) shows the damage distribution after using a new roll once. There is no damage near the roll surface, there is a damage peak a little further inside, and the damage gradually decreases as it gets closer to the center. , there will be zero hot water loss. The shear stress distribution itself is zero only on the roll surface, and at the curved position, it has a finite value of ・L, but since the fatigue limit is taken into consideration, the radius is ”, the damage distribution becomes sleepy. Therefore, this] damage will not remain in the water and will eventually disappear if the grinding is repeated, and with subsequent use, new damage will be caused, and at the same time, old damage will be replaced by grinding. As the fatigue damage distribution gradually disappears, the fatigue damage distribution settles down to a nearly steady state. The maximum value Fm of this steady state fatigue damage degree
aX depends on the amount of grinding, and selecting the amount of grinding such that Fmax < 1 is an important issue in operation.

According to the simulation program developed this time, it is possible to easily find such a limit amount of grinding. FIG. 5 shows the change in fatigue damage distribution when such a limit grinding amount is adopted and rolling and grinding are repeated. By repeating rolling and cutting, FmaX
increases, and the distribution shape gradually changes in a direction in which the degree of damage to the roll surface becomes more severe, and after the 13th grinding count, the damage distribution becomes a steady state. 1 in the figure is j per time
v1 grinding t, (a); grinding amount vo − (b) + td
f Grinding times it, 3, (C): Grinding times 5, (d
); Grinding number 7, (e) ; Grinding number Gino, (f)
: Indicates the number of grinding times 13.

In addition, in Fig. 4, we considered the case where the upper and lower sides of the intermediate roll and reinforcing roll can be inserted, but even by replacing the WS and DS of the intermediate roll and reinforcing roll, the fatigue damage to the rolls will be dispersed in exactly the same way, and the same result will be achieved. It is possible to obtain the effect of

Also, in Figure 4, upper F or (WS) for each reclassification.

I thought about replacing the DS, but one rolling
If the resulting fatigue damage is relatively small, repeat the rolling-grinding process at the same location, and then
Even if the method of replacing S is adopted, it may be effective.

Next, an embodiment of the rolling mill of the present invention will be described with reference to the drawings.

Figure 0 (1) shows an example of a roll and bearing design that allows the WS and DS of a confectionery roll to be interchanged.In general, radial loads are received by both the WS and DS, but thrust loads are applied to either one. In many cases, the roll is designed to be received by a bearing, so it is best for conventional rolls to have different WS and DS shapes depending on the shape of the shaft and edge.Also, the shape of the roll shaft end also leads to the DSV:J coupling. , WS-
In most cases, it is asymmetrical because it may receive force from the U-roll recombination device.

On the other hand, in Figure 6, the shape and dimensions of the rolls are completely symmetrical, allowing WS and DS to be interchanged. A radial bearing 21 and a thrust bearing 2s-7) are installed in the DS bearing box, and only a radial bearing 22 is installed in the WS bearing box. Therefore, the structure is such that the thrust load is received only by the DS bearing, but the roll shape is symmetrical. For WS bearings, a roll with a complicated shape as shown in the figure is unnecessary, but such a shape is not harmful. Furthermore, the shapes of the roll shaft ends are symmetrical so that both WS and DS are connected to the coupling. Even when the w's shaft end is used for roll change, if a suitable change jig is used, such a shape will not pose a problem.

In the case of reinforcing rolls, MJA movement is rare, so the shape of the roll shaft end can be matched to the recombination device. Further, in the case of reinforcing rolls, oil return bearings are often used as radial bearings, but even in that case, the roll shape can be designed to be symmetrical as shown in FIG. 6.

In the case of axially movable rolls, it is necessary to have smooth chamfers on the shoulders to avoid stress concentration. In conventional rolling mills that use the same rolls at the same position,
The chamfer was only attached to one side, but the WS
In order to create a rolling mill in which rolls can be installed by replacing the DS, it is sufficient to attach channels 7A to both sides as shown in FIG. Of course, even in this case, the bearing section must be designed as shown in Figure 6.

It does not have separate thrust bearings and radial bearings.

There may also be a type of bearing that combines tapered roller bearings, but in this case it would be even more difficult to make the rolls symmetrical.

In addition, in Figure 6, the bearing box is dedicated to WS and DS, and it is assumed that only the rolls are replaced with WS and DS, or if the m-box is designed to be compatible with iWs and DS, the entire bearing box can be used as WS and DS. It is also useful to replace them, and in this case there is no need to make the roll neck portion symmetrical.

In addition, in order to create a system in which the upper and lower sides of the axially movable rolls can be changed, chamfers may be provided on both sides as shown in FIG. 7, and the outer dimensions of the upper and lower rolls may be made the same.

Next, two embodiments C of the method of using the roll of the present invention will be explained.

Let's take as an example a case where a 6Hi mill is used in the rear three stands of a 6-stand Honto tandem mill, that is, No. 4, 5.6. The dimensions of the 6Hi mill are that the roll diameter is work roll 6.
00 dragon, medium M roll 750 tomo.

Roll body length with reinforced o-ru 140011N? J, 168
0 vx. The work roll is made of high-alloy grain material, and the intermediate roll and reinforcing roll are made of special forged steel material with a hardness of Hs'70. The rolling conditions are the operating conditions of a normal hot strip mill that rolls ordinary steel and special steel. )
The rolling load for No. 4 is 410-17/IIJton
(Mode 1070 tons), No. 5 is 200-11
80 tons (mode 970 tons), No. 6 is 200 tons
~l 180 ton (mode 740 ton). It is assumed that the intermediate roll is rolled under the condition that the body end of one of the rolls always coincides with the sheet end, that is, δ-〇.

Under these conditions, the effect of the method of using the roll on the amount of grinding of the reinforcing roll was estimated using the aforementioned simulation model. Limit research All when the reinforcing roll assembly cycle is set to the rolling length of No. 6 outlet side and is 6300 km.
t is shown in Table 1. In addition, the limit grinding amount is the maximum value Fmax when the fatigue damage product reaches a normal state by repeatedly performing rolling and fjf grinding as shown in Fig. 5.
max (means that the amount of grinding equal to 1 is f=e.

The upper row of Table 1 shows the conventional method in which the same rolls are installed in the same position, and the lower row shows the limit grinding amount when using the roll usage method of the present invention in which the upper and lower rolls are replaced every time the rolls are reassembled.

The results show that the amount of grinding is reduced by almost half by the method of the present invention, and a significant improvement in roll consumption can be achieved. Furthermore, the fact that the amount of grinding can be reduced in this way means that the roll change cycle can be significantly extended, and an improvement in the operating rate of the cutting mill can also be expected.

[Brief explanation of the drawing]

Figure 1(a) shows a six-high rolling mill with an intermediate roll shift system, (
b) is a 4-high rolling mill using work rolls, (C) is a 4-high rolling mill with a reinforced roll shift method, and (d) is a sleeve °/
An explanatory diagram of a foot-type 6-high rolling mill. Figure 2 shows the load distribution that each roll receives when the intermediate roll is rolled 7 feet in a 6-high rolling mill that uses intermediate rolls. Figure 4 shows the distribution of fatigue damage accumulated when using the reinforcing roll and intermediate roll in the trunk length direction. Fig. 5 is a longitudinal distribution diagram, Fig. 5 is a radial fatigue damage distribution diagram, and Fig. 6 is a diagram showing the fatigue damage distribution in the radial direction.
The top view and FIG. 7 are detailed explanatory views of the present invention. ”...Lower reinforcement roll 2...Upper intermediate roll 3.
...Top work roll 4...Bottom work roll...
-F Intermediate roll 6...Lower reinforcing roll I...
・Upper sleeve 8... Sleeve 9... Load distribution between reinforcing roll and intermediate roll 10... Load distribution between intermediate roll and work roll 11... Load distribution between work roll and rolled material□ 12... Mill Center 13...Distribution of wear and tear accumulated during the first use 14
・・Fatigue damage distribution remaining after grinding using the same method 15 ・・Fatigue damage distribution received after second use 16・・
・Fatigue damage distribution remaining after second use 17... Work roll body 18... Work roll neck 19... DS bearing box 20... WS bearing box 21... DS radial bearing 22...WS radial bearing 23...Thrust bearing 24...Thrust bearing holding fitting 25...DS chamfer 26...
WS Chamfer (C)
(d) / Figure 2 (α) (b) Hayabusa 3 times (α) IC power during instant roll (b) Roll RFI + middle power during f huge rain color Figure 4 ( Q) Roll n same length middle I (no ryo giant enemy (b) roll side & home IC 6 u Q company doo no. 5121 (0-) (b)
' (C) Tsu & Sacred 11) (d) (e) (f) 6th
I21 Table 7 Procedural Amendment (Spontaneous) 1935, 11th year, June 1973, Japan Patent Office Commissioner Shima 1) Haru, Mojoden 1 Case Display Patent Application No. 160091 of 1988 2 Title of Invention Method of using rolling rolls and its use Person making device 3 amendment Relationship to case Patent applicant location 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name (665)
Nippon Steel Food Coloring Representative Takeshi 1) Toyota 4th generation Osamu Address 3-3-3-3 Nihonbashi, Chuo-ku, Tokyo Date of amendment order Showa year Month/day (shipment date) 6 Number of inventions increased by amendment 1. Amend the claims as shown in the attached sheet. 2. On page 5 of the specification, line 17, "having, axial direction" is corrected to "having, axial direction". 3 On page 16, line 14, "normal state" is corrected to "steady state." Attachment 1r, II# Scope 1 When a metal plate is rolled by a rolling mill having at least one pair of rolls that are movable in the axial direction, contact with the rolls that are movable in the axial direction and the rolling mill is provided. A method of using rolls in plate rolling, characterized in that at least one pair of rolls among the rotating rolls is used with the "-1Ks side and the working side of each roll switched when used up to that time. 2. At least one pair of rolls. When rolling a metal plate using a rolling mill having four rolls that are movable in the axial direction, at least one pair of the rolls that are movable in the axial direction and the roll that rotates in contact with the rolls are A method of using rolls in plate rolling, characterized in that the upper and lower sides of the metal plate passing line are used interchangeably during use.3 At least one pair of rolls is movable in the axial direction b4
In this rolling mill, there is provided a pair of rolls movable in the direction of the workpiece having coupling means for the axial displacement driving means at both axial ends thereof, and coupling means for the rotational drive source at both axial ends thereof. 4. A rolling mill configured to have one or both of a pair of work rolls so that the working side and drive side of the rolls can be replaced and incorporated; 4. A rolling mill configured to have at least one pair of rolls movable in the axial direction. A rolling mill comprising a pair of axially movable rolls having shoulder drop portions on both sides in the axial direction so that the upper and lower sides of the sheet passing line can be replaced and installed.

Claims (1)

[Scope of Claims] 1. When rolling a metal plate using a rolling mill in which at least one pair of rolls is configured to be movable in the axial direction, at least one pair of the axially movable rolls and a roll that rotates in contact with the axially movable rolls. A method of using rolls in plate rolling, characterized in that the drive side and work side of each roll are used interchangeably. 2. At least one pair of rolls can be moved in the axial direction. When a metal plate is rolled by the configured rolling mill, at least one pair of the axially movable roll and the roll that rotates in contact with the axially movable roll is, of course, above the metal plate passing line during previous use. How to use rolls in plate rolling ib. 3 Move at least one pair of rolls in the axial direction? A rolling mill configured to have +J function includes an axially movable roll pair having axial displacement and coupling means to the drive means at both ends in the axial direction, and a coupling means to the rotational drive source. A rolling mill having one or both of a pair of work rolls at both ends in the axial direction, so that the working side and the driving side of the rolls can be replaced and installed. , 1 In a rolling mill in which at least one pair of rolls is configured to be movable in the axial direction, a pair of rolls that are movable in the axial direction and having shoulder drop portions on both sides in the axial direction is provided, and the upper side of the one-thread sheet line is A rolling mill configured so that the front side can be replaced and installed.