JPH0475704A - Rolling method - Google Patents

Abstract

PURPOSE:To reduce drawing-down force by specifying the inclined angle of the wall surface of recessed part in the rolling direction in the case of rolling that a fluid for lubrication is confined in the recessed part on the surface of material to be rolled. CONSTITUTION:In a rolling mill 11 with a machine 13 for making recessed part with which the recessed parts 12 on both surface of a band plate M are made, the inclined angle of the wall surface of the recessed parts 12 in the rolling direction is taken as 30 - 65 deg.C to the surface of the band plate. In this way, the reduction effect of rolling load is displayed by biting the fluid L for lubrication in the recessed parts 12 and also the surface isn't made into a double skin by preventing inclination inwards the wall surface at the time of rolling. As a result, drawing-down force can be reduced without bringing the deterioration of rolled stock.

Description

[Detailed Description of the Invention] <Industry> Utilization Summary The present invention relates to a rolling method Lr for rolling a metal plate such as steel or aluminum with a large reduction.

<Prior Art> Conventionally, for example, strips of nets, aluminum, etc., have been rolled as rolling stock, for example, in the case of hot rolling, and in the case of pot strip mill cold rolling. Each tandem cold mill is used to extend the strip by sandwiching the strip between a pair of upper and lower rotating work rolls. j between the work roll and the strip that occurs during this rolling.
Second, conventionally, a fluid such as a rolling lubricant has been supplied to the work roll surface, thereby reducing the load required for plastic deformation. Further, at the same time as rolling, the wetting agent l (-y) prevents wear of the work rolls and occurrence of scratches on the surface of the rolled material.

However, in the case of hot rolling, for example, the temperature of the strip reaches approximately 1200°C = 900°C, and the rolling lubricant supplied to the work rolls generally burns and becomes a fluid lubricant when the temperature exceeds 200°C. function is lost. The rolling lubricant applied to only a small portion of the work roll only exhibits a lubricating effect, and the effect is insufficient, resulting in increased roll wear. With this increase in wear of the rolls, the friction between the strip and the rows increases, and therefore it is necessary to apply a high rolling load to maintain the rolling reduction of the strip.

In addition, in conventional hot rolling, there is no fluid other than air between the work rolls and the strip, and air cannot act as a boundary film due to its compressibility, so the entire area of the strip is It is thought that a state of boundary friction occurs where metals come into contact with each other. Therefore, the coefficient of friction between the work roll and the strip is at least μ≧062, which causes problems such as increased rolling load, rough surface of the roll, and wear of the roll.

On the other hand, in the case of cold rolling, the arc of contact between the strip and the work rolls that roll it is under ultra-high pressure in order to increase the rolling reduction, and rolling lubricant is applied to the arc of contact with the rolls. There was a problem in that the lubricating effect could not be sufficiently exerted because it could not penetrate sufficiently.

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 invention has filed an application for a rolling method in which the material is introduced between work rolls and rolled under conditions of fluid lubrication (Japanese Patent Application No. 119313/1983).

As a result, 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> When recesses are provided to reduce the friction coefficient of the rolled material and the rolling load, the shape of the recesses is important, and if the shape of the recesses is inappropriate, There was a risk that the side walls of the recess would collapse inward, resulting in a double skin, which would deteriorate the quality of the rolled material.

The present invention has been made in view of the above circumstances, and provides a rolling method that can efficiently reduce the friction coefficient of a rolled material without degrading the quality of the rolled material, thereby facilitating the achievement of a high rolling reduction. The purpose is to prevent quality deterioration.

<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 method is characterized in that the inclination angle of the wall surface of the recess in the rolling direction with respect to the surface of the material to be rolled is from 30 degrees to 65 degrees.

Function> By setting the inclination angle of the recessed wall surface to 30 degrees or more, the inflow of lubricating fluid is ensured, and by setting it to 65 degrees or less, the wall surface is prevented from collapsing toward the inner surface during rolling.

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 includes a rolling mill 11 that rolls the strip M, and a recess forming machine 13 that forms 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 and 15 for rolling the strip M, and these upper and lower work rolls 14 and 15.
a backup roll 16 that rolls into contact so as to receive the reaction force of
17 are each rotatably supported by the housing 18.

Also, so as to spray a lubricating fluid (for example, water) L onto each contact portion between the work rolls 14 and 15 and the strip M,
Nozzles 19, 20 are each arranged.

In the recess forming machine 13 provided on the upstream side of the rolling mill 11, a pair of protruding pinch rolls 22 and 23 having a large number of protrusions 21 as shown in FIG. It is rotatably supported by the housing 24.

Moreover, these vinyl rolls 22 and 23 pinch the strip M with such pressure that the concave portions 12 corresponding to the protrusions 21 are transferred by plastic deformation of the strip M being conveyed.

Therefore, when the strip M is conveyed in the right direction in FIG.
A large number of recesses 12 are formed on both surfaces. Further, the strip M with the recessed portion 12 formed therein is conveyed to the rolling mill 11, and then the work roll 14. Where is the contact area between Is and the strip M sprayed? iFluid 1. Wa crawl 14°15
Before it is bitten into the contact arc σ of j2, it is stored in the recess 12. Thereafter, the strip M is rolled, and a fluid page for lubrication is formed in the recess 12 at the filter edge.

is temporarily closed in the recess 12 due to contact between the surface of the work roll 14 and 15 and the opening edge of the fourth part 2.
Two can be put in. Alternatively, liquid adhering to the surfaces of the work rolls 14 and 15 is introduced into the four parts 12 as the work rolls 14p to 15 rotate. Furthermore, as it is rolled, the fluid I- is closed in these four parts 12.
The recess 12 is gradually thinned out within the contact arc, thereby forming a limiting film over the contact area between the work roll 14.15 and the strip M. Due to the formation of this boundary film, a large amount of fluid remains in the contact portion α during rolling of the strip M, thereby reducing wear on the strip M.

In addition, by providing a large number of four parts 12 on the strip M, the fluid can be sprayed to the extent that it accumulates in the recesses 12 to contain it.
Therefore, the amount of indigo used for fluid (4) can be reduced.

Here, the general formula for the frictional shear stress that acts between the roll and the strip due to the reduction in the coefficient of friction between the leak roll and the strip according to the present invention is shown below.

r - two a τ, + (1-a) τ.

Here, τゎ-・μP: Boundary friction area μ: Boundary friction coefficient P: Roll surface pressure ヮ: Liquid viscosity u, w5. Body velocity h: fluid thickness + l: area ratio of boundary friction region Usually, 7 = 0.2-0.5, r, >> r.

Therefore, if the area ratio a is decreased, the frictional shear stress τ
You can make small pomegranates.

That is, in order to reduce this area ratio β, a large number of recesses j2 are formed on the surface of the strip M before rolling, and the fluid T- is confined in the recesses 12 during rolling.

Therefore, it is possible to confine the fluid in the recesses 11iX12 formed in the cloth plate M, and to arbitrarily adjust the value of the ml volume ratio a.

In addition, the fluid lubrication effect can be enhanced by trapping the fluid 1- in the recess 12.

In addition to water, the pond sewage fluid used is a mixture of lubricating oil such as mineral oil or water-cleaning oil, and especially in the case of hot rolling, the temperature conditions of the strip may be The shape of the pinch type will be explained in detail based on Figures 5 and 6, as well as glass.

Figure 5 shows the view from the ■-■ arrow in Figure 3, and Figure 6 shows the '':
V [-M line arrow view in Figure J, Figure 7: r is ■- in Figure 5
■715 stones as shown by the arrow.

J, sea urchin, pinch roll 22 shown in FIGS. 5 to 7,
The protrusion 21 of No. 23 has an angle of 60° in the front side in the rolling direction, an angle of 45° in the rear side, an angle of 50° in the width direction, and a top side length in the rolling direction of 5-5Wllll1. 6 m
, has a truncated east-west hoko shape with a height of 3 ms+.

By forming the recess 12 in the strip plate M by setting the ratio δ/δ of the depth of the recess 12 of the girder plate M to the height of the protrusion 21 of the pinch squares 22, 23 to 0.1-0.8. , the area ratio of the recessed portion 12 of the girder plate M is 20-70%.

The shape of the recess 12 of the girder plate M will be explained in detail based on FIG.

8 shows a view from ■ to m in FIG. 4, and FIG. 9 shows a view from ■ to ■ in FIG. 4.

As shown in FIG. 8, the angle θ of the mural 12a in the ring direction of the band plate M in the concave portion 12 is ! 50° to the IF plane,
Also, as shown in Fig. 9, the front side in the rolling direction! The angle of the surface 12b is 60 degrees with respect to the surface, and the angle of the wall surface 12C on the rear side in the rolling direction is 45 degrees with respect to the surface.

In other words, the angle of inclination of the wall surface of the recess with respect to the rolling direction is 30'
It is between 65° and 65°.

As shown in FIGS. 10 and 11, the angle θ of the wall surface of the recess
Regarding the relationship between the rolling blade and the rolling blade, when θ is about 25°9 higher, the rolling blade decreases and becomes an effective range for the rolling force reduction effect.

As shown in FIG. 12(a), the angle θ of the recess wall surface is 20
In the case below, the lubricating fluid is not bitten into the recess 12 and the rolling load is not reduced. As shown in FIG. 12(b), when the angle θ of the wall surface of the recess increases by 30°, the lubricating fluid is bitten into the recess 12 and the effect of reducing the rolling load is exerted.

As shown in Fig. 13 (al), when the angles θ2 and θ3 of the wall surfaces of the recess on the front and rear sides in the rolling direction are 65° or less, as shown in Fig. 13 (b
), the surface of the strip M becomes flat. As shown in Fig. 14 (al), when the angle θ2° θ of the wall surface of the recess on the front and rear sides in the rolling direction exceeds 65°, the strip M double-skinned areas are formed on the surface, deteriorating the surface quality.

In the above-described rolling method, the angle θ2. Since θ3 is set between 30° and 65°, the lubricating fluid is bitten into the recess 12 and the rolling load reduction effect is exhibited, and a double skin portion is formed on the surface of the strip M. never be done.

<Effects of the Invention> In the rolling method of the present invention, since the inclination angle of the recess wall surface in the rolling direction with respect to the surface of the material to be rolled is set from 30 degrees to 65 degrees,
The lubricating fluid is trapped in the recesses to reduce the rolling load, and the wall surface is prevented from collapsing into the inner surface during rolling, so the surface does not become double skinned. As a result, it is possible to reduce the number of rolling edges without degrading the quality of the rolled material.

[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, and No. 2'/I! J is an enlarged view of the main parts, FIG. 3 is a perspective view of the pinch roll, FIG. 4 is a perspective view of the strip plate provided with the concave portion 1, and FIG. 5 is a view taken along the line ■-■ in FIG. 3. , FIG. 6 is a view taken along the ■-M line in FIG. 5, FIG. 7 is a view taken along the ■-■ line in FIG. 5, and FIG. 8 is a view taken along the ■-■ line in FIG.
Fig. 9 is a view from the ff-N arrow in Fig. 4, Fig. 10 is an explanatory view of the side wall of the recess, Fig. 11 is a graph showing the relationship between the side wall angle and the rolling blade, and Fig. 12 (al, (bl are Fig. 13(a) is a sectional view showing the state of fluid entrainment. (bl is an explanatory drawing showing the normal rolling state, Fig. 14(a)
1, (bl is an explanatory diagram showing the rolling state of double skin. In the drawing, 10 is a rolling device, 11 is a rolling mill, 12 is a recess, 13 is a recess imparting machine, 14.15 is a work roll, 22. 23 is a pinch roll, L is a fluid, θ is a wall angle, and M is a strip plate.

Claims (1)

[Claims] In 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 angle of inclination of the wall surface of the recess in the rolling direction with respect to the surface of the material to be rolled is 30
A rolling method characterized by rolling at an angle of 65° to 65°.