JPH0446605A - Reducing method of rolling load - Google Patents

Abstract

PURPOSE:To reduce the frictional force between a material to be rolled and a work roll for rolling and to obtain the reduction effect of drawing-down force by forming many recesses on the surface of the material to be rolled and constituting so that the size of the recesses is made into a specified size. CONSTITUTION:A lubricant 3 which is supplied between the material l to be rolled and the inlet side of the work roll 2 for rolling is advanced as it is stored in the many recesses 5 which are provided on the surface of the material 1 to be rolled and the recesses 5 on the surface of the material to be rolled are covered by bringing the work roll 2 into contact. When rolling prceeds further, the volume of recesses 5 is decreased, the pressure of the lubricant 3 is raised and lubricating effect is exhibited. When rolling proceeds furthermore and the tip of recessed part in the rolling direction comes out of the bite area, the lubricant 3 is released to the air, its pressure is lowered and lubricating effect is eliminated. At the above progress, when the length L1 of the recess 5 in the rolling direction is >=3mm and taken as <=30% of the arc of contact which is formed with the work roll 2 and the material l to be rolled, pressure reduction effect is exhibited by the ratio of the area of the region where is present in the section until the tip of the recess 5 reaches the exit of the bite area and where lubrication is effectively executed to the total area of the bite area.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for reducing rolling load by which metal strips, shaped steel, steel bars, etc., such as steel and aluminum, can be rolled with a reduced coefficient of friction.

[Conventional technology]

Conventionally, for rolling strips of steel, aluminum, etc., hot strip mills have been used for hot rolling, and tandem cold mills have been used for cold rolling. By sandwiching the strip between a pair of upper and lower rotating work rolls, the strip is stretched thin. In order to reduce the friction between the work roll and the strip that occurs during rolling, fluids such as rolling lubricants have traditionally been supplied to the work roll surface, thereby reducing the load required for plastic working. There is. At the same time, the lubricant prevents wear of the work rolls and the occurrence of scratches on the surface of the rolled material.

[Problem to be solved by the invention]

However, in the case of hot rolling, for example, the temperature of the strip reaches a high temperature of approximately 1200 to 900°C, and the rolling lubricant supplied to the work roll surface generally burns when the temperature exceeds 200°C, resulting in fluid lubrication. It loses its function as an agent. Further, the rolling lubricant adhering to a small portion of the surface of the work roll only exhibits a lubricating effect, and the effect is insufficient, resulting in a problem in which almost no reduction in load can be expected.

In addition, in conventional hot rolling, only air exists between the work roll and the strip, and air cannot act as a boundary film due to its compressibility, so the metals come into contact with each other throughout the strip. Therefore, the friction coefficient during this period is at least μ≧02, which causes problems such as an increase in rolling load, rough skin of the roll, and an increase in the amount of roll wear.

On the other hand, in the case of cold rolling, the inside of the contact arc between the strip and the work roll that rolls it is under ultra-high pressure to increase the reduction ratio, and the rolling lubricant is inside the contact arc with this roll. There is a problem that the lubricating effect cannot be fully exerted because the lubricating effect cannot be sufficiently penetrated.

The present invention aims to provide a new rolling load reduction method that solves the above-mentioned problems.

[Means to solve the problem]

For this reason, the rolling load reduction method of the present invention includes rolling means that performs rolling while supplying lubricating fluid between the material to be rolled and the entry side of the rolling work roll. A recess is formed, and the size of the recess is configured such that the opening length in the rolling direction is 3 or more and 30% or less of the contact arc length between the work roll and the rolled material. .

[Effect]

In the rolling load reduction method of the present invention described above, the lubricant supplied between the rolled material and the entry side of the rolling work roll progresses while being stored in the many depressions provided on the surface of the rolled material. The rolls come into contact and cover the dents on the surface of the rolled material. As the rolling progresses further, the volume of the depression decreases, the pressure of the lubricant increases, and a lubricating effect is exerted. Further, as the rolling progresses and the tip of the recess in the rolling direction comes out of the bite area, the lubricant is exposed to the atmosphere, the pressure decreases, and the lubricant loses its lubricating effect.

In the above process, when the length of the recess in the rolling direction is 3 m or more as in the present invention, it has been experimentally shown that the lubricant is effectively stored in the recess. In addition, if the contact arc length is 30 inches or less, the area where lubrication is effectively performed exists in the section from when the rear end of the recess in the rolling direction is covered by the work roll until the tip of the recess reaches the exit of the bite area. The ratio of area q to the total area of the bite area is sufficient to obtain the rolling force reduction effect.

〔Example〕

One embodiment of the present invention will be described below in the drawings.
FIG. 1 is an explanatory view showing the operating state of the present invention, and FIG. 2 is a functional diagram showing experimental values of the rolling force of rolling according to the present invention.

In Fig. 1, ■ is the material to be rolled, and there are many dents 5 on the surface.
has been established. 2 is a rolling work roll, 3 is a nozzle 4
The lubricant 3 is supplied between the material to be rolled 1 and the entry side of the rolling work roll 20. Lubricant 3
For example, water, oil, etc. are used.

The opening length (diameter) Ll in the rolling direction of the recess 5 provided on the surface of the rolled material 1 before rolling is 3 or more, and is formed to be less than 30% of the contact arc length Le between the work roll 2 and the rolled material 1. are doing.

That is, L, )3m, and Lc<0.3. R is the roll diameter of the work roll 2, and under the above conditions, R=200 tanφ. Further, in this case, the entrance side thickness t of the rolled material 1 is 20 wn t.

Lp indicates the amount of one-sided reduction, and in this case Lp=6m.

Next, to explain its effect, a lubricant (for example, water) is applied to the rolled material l and the work roll 2 at the input side of rolling.
When the material to be rolled 1 is rolled by the work rolls 2 while being fed between them, water is bitten into the depressions 5 on the surface of the material to be rolled 1. During rolling, this water is subjected to pressure as the recesses are deformed as shown in the first figure, and serves as a lubricant between the work roll 2 and the rolled material 1.

Next, to explain the rolling force of the rolling according to the present invention with reference to FIG. 2, 10 indicates the rolling force when a flat material with no dents on the surface of the rolled material is rolled while supplying lubricant, as in the conventional method, 11 is a reduction blade used when rolling a material with many dents on the surface of the material to be rolled while supplying lubricant as in the present invention, whereas in the conventional method, the reduction blade is removed as shown in the figure. In the case of the method of the present invention in which the recess diameter L1 is large and the diameter L1 of the recess is 3 rran or more and L/C is smaller than o3, the rolling blade is small, and a reduction in the rolling blade by 40 inches at the maximum has been realized.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various design changes can be made within the scope of the technical idea of the present invention.

〔Effect of the invention〕

According to the present invention, due to the effect of reducing the frictional force between the material to be rolled and the rolling work roll, the rolling reduction ratio can be increased by about 20 inches using the same rolling blade as in the past, and it is possible to downsize the rolling equipment. Further, if rolling is performed at the same rolling reduction ratio as in the past, the load on the rolling mill is reduced, so running costs and work roll maintenance can be reduced.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the working state of one embodiment of the present invention, and FIG. 2 is a functional diagram showing experimental values of the rolling reduction blade according to the present invention. ■... Material to be rolled, 2... Work roll for rolling, 3... Lubricating material, 4... Nozzle, 5
...Concavity, L, ...Diameter of the concavity in the rolling direction, L, ...Contact arc length,
R...Rolling work roll diameter, t...Thickness of rolled material, Lp...One side rolling amount. Ha2 leap. (Side Party Procedural Correction Officer (Volunteer) June 20, 1990

Claims (1)

[Claims] (1) In a rolling means that performs rolling while supplying a lubricating fluid between the material to be rolled and the entry side of the rolling work roll, a number of depressions are formed on the surface of the material to be rolled, and the depressions are A rolling load reduction method characterized in that the opening length in the rolling direction is 3 mm or more and is 30% or less of the contact arc length between the work roll and the rolled material.