JPH0475705A - Rolling method - Google Patents

Abstract

PURPOSE:To reduce drawing-down force by specifying the ratio of the wall surface of recessed part to the total area of rolled stock in the case of rolling the material to be rolled that is rolled by confining a fluid for lubrication in the recessed part on the surface of material to be rolled. CONSTITUTION:In a rolling mill 11 with a machine 13 for adding recessed part with which the recessed parts 12 are formed on both surfaces of a band plate M, the fluid L for lubrication is sprayed on the contact part between work rolls 14, 15 and the band plate M when the band plate M is transported into the rolling mill 11 and the fluid L is temporarily confined in the recessed parts 12. At this time, the area ratio of the recessed part 12 to the total surface area of the bank plate M is taken as 20 - 70%. In this way, the boundary film is formed over the contact part between the work rolls 14, 15 and the band plate M and roll wear is decreased, so rolling load can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a rolling method for hot rolling a metal plate such as W42 aluminum to a large reduction.

<Prior art> A hot strip mill has traditionally been used for hot rolling to roll a strip of IP aluminum, etc. In this hot strip mill, the strip is rolled between a pair of upper and lower rotating work rolls. By sandwiching the board I
In order to reduce the friction between the work roll and the strip that occurs during rolling, a fluid such as a rolling lubricant has traditionally been supplied to the surface of the work roll. This reduces the load required for plastic deformation.

Moreover, at the same time, the R lubricant prevents wear of the work rolls and the occurrence of scratches on the surface of the rolled material.

However, in the case of hot rolling, the temperature of the strip is approximately ], 20
The temperature reaches 0°C to 900°C, and the rolled R11l material supplied to the work roll will burn if the temperature exceeds 200°C and lose its function as a fluid stirring material. The rolling lI# agent attached to a small portion of the work roll only exerts a lubricating effect, and the effect is insufficient.
Roll wear will increase. With this increase in roll wear, the coefficient of friction between the strip and the four wheels increased, and therefore it was necessary to apply a high rolling load to maintain the rolling reduction of the strip.

In order to solve this problem, as a method that can reliably and effectively reduce the coefficient of friction between the roll and the plate, a recess is formed on the surface of the strip before rolling, and the fluid is trapped in the recess. The applicant of the present application has filed an application for a rolling method in which the material is directly introduced between work rolls and rolled under conditions of fluid lubrication (Japanese Patent Application No. 119313/1983).

Thereby, the coefficient of friction during rolling of the material to be rolled can be reduced, and a high rolling reduction ratio can be obtained even if the rolling load is significantly reduced.

<Problem to be solved by the invention> In order to reduce the friction coefficient of the rolled material and reduce the rolling load, the proportion of concave parts is important, and if the proportion of concave parts is inappropriate, hydrodynamic lubrication conditions cannot be established. Therefore, the friction coefficient cannot be sufficiently reduced.

The present invention has been made in view of the above situation, and an object of the present invention is to provide a rolling method that can more efficiently reduce the coefficient of friction of a rolled material, thereby facilitating the combination of a high rolling reduction.

<Means for Solving the Problems> A rolling method of the present invention for achieving the above object is a rolling method in which a recess is formed on the surface of a material to be rolled, and rolling is performed while a lubricating fluid is confined in the recess. The area ratio of the recess to the total surface area of the rolled material is 20% to 70%.
It is characterized by the following.

<Function> By setting the area ratio of the recess to 20% or more, the rolling load during hot rolling is reduced, and by reducing the area ratio of the recess to 70% or less, the mouth recess can be formed by plastic working. The load will not become excessive.

Embodiments FIG. 1 shows a schematic configuration of a rolling apparatus for carrying out a rolling method according to an embodiment of the present invention, and FIG. 2 shows an enlarged view of the main parts thereof.

The rolling apparatus 10 has a rolling mill 11 for rolling the strip M, and a recess forming machine 13 for forming recesses 12 on both sides of the strip M on the entry side of the rolling mill 11.

This rolling mill 11 includes upper and lower work rolls 14.15 that piezoelectrically apply the strip M, and backup rolls 16 and 17 that roll in contact with each other to receive the reaction force of these work rolls 14.15.
are each rotatably supported by the housing 18.

In addition, the work rolls 14, 15 and the strip M are sprayed with a lubricating fluid (for example, water) L at their respective contact portions.
Nozzles 19 and 20 are arranged respectively.

A pair of protrusion-equipped vinyl rolls 22 and 23 having a large number of protrusions 21 as shown in FIG.
* It is rotatably supported by the housing 24 like a scoop 6'4. '23 is a concave @12 corresponding to the protrusion Ia21 due to the flexible deformation of the belt plate being conveyed.
The strip M is clamped with such pressure that it is transferred.

Therefore, when the strip M is conveyed in the right direction in FIG.
A large number of recesses 12 are formed on both surfaces. Furthermore, when the strip M in which the recessed portion 12 is formed is conveyed to the rolling mill 11,
The fluid sprayed onto the contact area between the work rolls 14 and 15 and the strip M is collected in the recess 12 before being bitten into the contact arc α of the work rolls 14 and 15. Thereafter, when the strip M is rolled, the lubricating fluid in the recess 12 is temporarily reduced by contact between the surfaces of the work marls 14 and 15 and the opening edge of the recess 12. Trapped inside. Alternatively, it is introduced into the recess 12 as the work rolls 14, 15 rotate. Furthermore, as the rolling process progresses, the fluid trapped in these recesses 12 is gradually stretched thinner within the contact arc, and as a result, the fluid trapped in these recesses 12 is transferred to the contact area between the work rolls 14 and 16 and the strip M. This forms a limiting membrane. Due to the formation of this boundary film, a large amount of fluid ■- flows into the contact arc α during rolling of the strip M.
It remains within the range, reducing roll wear.

Further, by providing a large number of recesses 12 in the girder plate M, it is sufficient to spray and contain as much fluid as is accumulated in the recesses 12, so that the amount of fluid used can be reduced compared to the conventional method.

Here, 1llIWA of the work roll and strip of the present invention
Due to the decrease of the coefficient, the fist W that acts on the opening between the roll and the strip
The general formula for A shear stress T is shown below in 9.

τ2 ατ 工＋(1−a　)　τ.

Here, r, 3-μP: 11 boundary friction area μ: boundary friction coefficient P: roll surface pressure rl: viscosity of liquid U: distance of liquid h: thickness of liquid tIjl interface thickness area ratio of rattan area Usually, μ=(12-0,5,τ4,).

Therefore, if the area ratio of the nose is reduced, III! The wA shear stress τ can be reduced.

That is, in order to reduce this area ratio effect, a large number of r! ! 3 part 129: is formed in advance, and the fluid is sealed in this recessed part 12 for rolling. Therefore, in the recess 12 formed in the strip M, the fluid ■
It becomes possible to confine.

Also, a small amount of fluid Lt? Just by inserting R into the recess 12, the fluid [? I hope you can increase your effectiveness.

In addition to water, the lli lubricating fluid to be used is lfi oil such as mineral oil as in the past, or a mixture of water and lubricating oil.Especially in the case of hot rolling, the S degree condition of the strip is used. (
Molten salts, glass, etc. that become liquid at high temperatures) may also be used.

Here, the shape of the vintilol will be explained in detail based on FIGS. 5.6 and 7.

Fig. 5 shows the ■-V line arrow view in Fig. 3, Fig. 6 shows the VI-M training arrow view in Fig. 5, and Fig. 117 shows the ■-■ Takashi arrow view in Fig. 5. This is an indication.

As shown in FIGS. 5 to 7, Vinci rolls 22, 2
The protrusion 21 of No. 3 has a front angle of 60 degrees in the rolling direction, a rear angle of 45 degrees, an angle of 50 degrees in the width direction, a top side length in the rolling direction of 5.5 degrees, and a top side length in the width direction. The size is 6, and the height is 3m.
The cut 1[12!1 is pyramid-shaped.

[! By forming the recesses 12 in the strip M by setting the depth ratio δ/δ of 1s12 to 0.1 to 0.8, the area ratio of the recesses 12 in the strip M becomes 20 to 70%.

The relationship of the rolling blade to the area ratio β of the recessed portion 12 is shown in No. 8M. The rolling conditions are l〇- and 30 mm thick universal steel.
It was heated to 100°C and rolled using rolls with a diameter of 230 m.

As can be seen from the figure, when the area ratio β of the recessed portion 12 is O12 or more, the rolling force is significantly reduced.

Therefore, by carrying out rolling with the area ratio β of the concave portions 12 of the strip M being 20% or more, the rolling load during hot rolling can be reduced.

Next, il [the load when the concave portion 12 is plastically worked on the surface of the strip plate M by rotating the pinch rolls 22 and 23 with the strip plate M sandwiched between a pair of pinch rolls 2223 of 200 mm, and the concave portion] 2. The relationship with the surface ratio β is shown in FIG. There are 10 strips
- Common steel with thicknesses of 220 m and 30 m was used.

As can be seen from the figure, when the area ratio β of the recess 12 becomes O27 or more, the load increases rapidly and approaches the forming limit. Therefore, by setting the area ratio β of the recesses 12 of the strip M to 70% or less, the recesses 12 that can reduce the rolling load can be formed with a relatively small load.

According to the above-described rolling method, the area 1 of the recess 12 of the strip M
Since 1 go β is set to 20% or more and 70% or less, the rolling load during hot rolling can be reduced to 11IE''c!, and the load for forming the concave portion 12 by plating is prevented from becoming excessive. can.

<Effects of the Invention> The rolling method of the present invention is a rolling method in which a lubricating fluid is confined in the recesses of a material to be rolled, and the area ratio of the recesses to the total surface area of the material to be rolled is increased from 20% to 70%. Therefore, it is possible to reduce the rolling load during hot rolling, and it is also possible to prevent the load for forming the recesses by plastic working from becoming excessive.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a rolling apparatus for carrying out a rolling method according to an embodiment of the present invention, Fig. 2 is an enlarged view of its main parts, Fig. 3 is a perspective view of a pinch roll, and Fig. 4 shows a recessed part. A perspective view of the provided strip plate, FIG. 5 is a view taken along the ■-V line in FIG. 3, FIG. 6 is a view taken along the ■-■ line in FIG. 5, and FIG. Fig. 8 is a graph showing the area ratio of the rolling blade and the recess, and Fig. 9 is a graph showing the load and the area ratio of the recess. In the drawings, 10 is a rolling device, 11 is a rolling machine, 12 is a recess, 13 is a recess forming machine, 12.15 is a work roll, 22.23 is a pinch roll, L is a fluid, and M is a strip plate.

Claims (1)

[Claims] In a rolling method in which recesses are formed on the surface of a material to be rolled and a lubricating fluid is confined in the recesses during rolling, the area ratio of the recesses to the total surface area of the material to be rolled is set from 20% to 70%. Characteristic rolling method.