JPS5922681A - Method for coating lubricant on steel plate - Google Patents

Abstract

PURPOSE:To heighten the accuracy of coating of a lubricant by making at least one of a doctor roll and a coating roll variable by a roll crown pressure regulating mechanism, and correcting the amount of roll crown basing on distribution of the thickness of oil film. CONSTITUTION:A doctor roll 1 and a coating roll 2 are made to one set, and a nozzle 3 is placed between the two rolls. A solution of solid lubricant sent from a lubricant tank 4 is sprayed and coated on the surface and back of a steel plate uniformly. In this case, the coating roll 2 is formed to a variable crown roll structure and the distribution of the thickness of oil film in the direction of width of the surface of the steel plate after coating the lubricant is measured by an oil film measuring device 5. The crown of the coating roll 2 is regulated basing on the result of measurement. As the coating roll 2 uses an elastic material, pressure regulating sections 21a, 21b that act simultaneously over the whole circumferential direction are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for uniformly applying a solid lubricating solvent to the front and back surfaces of a steel plate.

There is a step in which a solid lubricant solution is applied in the form of a film to the front and back surfaces of a cold-rolled steel sheet for rust prevention and other purposes. Conventionally, this lubricant application has been performed using a set of a doctor roll and a coating roll, and the lubricant contained in a container is first scooped out by the doctor roll, transferred to the coating roll to reduce unevenness, and then the coating roll is used to coat the steel plate surface. As shown in Fig. 1, a nozzle 6 is arranged between the coating roll 1 and the coating roll 2 to supply lubricant between the rolls, and the coating is applied uniformly by holding both rolls together. The method used was to increase the temperature and then apply it to the surface of the steel plate using a coating roll.

The oil film formed on the surface of a steel plate when applied by such a roll is usually thinner in the center and thicker toward the edges, resulting in an uneven condition in the width direction of the steel plate, as shown in Figure 2. was occurring.

For example, conventionally, for a target thickness (1) of 1μ, the central part (T1
) is 05μ, both edges (T2)
The non-uniformity was as high as 2μ. Conventionally, methods for adjusting the non-uniformity of the film thickness include adjusting the gap between two types of rolls, adjusting the rolling blade of the coating roll against the steel plate, or adjusting the viscosity of the coating solution. However, the adjustment process itself was difficult, took time, and the results were not always desirable.

An object of the present invention is to provide a means that can easily adjust the non-uniformity of the coating film thickness in the board width direction, improve lubricant application efficiency and application accuracy, and increase economic efficiency through effective use of lubricant. It is in.

The structure of the present invention is as shown in FIG.
and a coating roll 2, and a nozzle 6 is arranged between the doctor roll and the coating roll to spray and supply a solid lubricant solution sent from a lubricant tank 4, and it is evened out by holding both rolls together. The basic structure is that a coating roll 2 coats the front and back surfaces of a steel plate 5. The method of the present invention is that the coating roll 2, which is a direct coating roll, is formed into a variable crown roll (hereinafter referred to as VC roll) structure, and that the coating thickness distribution in the width direction of the steel plate surface after coating is measured using an oil film measuring device. 5, and the crown of the coating roll 2 is adjusted based on the measurement results.

Since the coating roll 2 uses an elastic material such as hard rubber, the coating roll 2 is coated at, for example, four positions in the longitudinal direction of the coating roll 2 over the entire circumferential direction, as shown in FIG. Pressure adjustment parts 21α and 21h that operate simultaneously are provided, and the pressure adjustment parts at these four locations are at least two systems, and in the case of two systems, the central side 2
The locations are grouped into the same system, and the two locations on the edge side are grouped into the same system so that they can be operated separately. Therefore, when pressurizing only the two pressure adjustment parts 21a on the central side, the roll crown is in the convex crown state α
On the contrary, when only the two pressure adjustment portions 21b on both edge sides are pressurized, a concave crown state is created.

In the method of the present invention, as shown in FIG. 1, pressurized fluid is supplied from a fluid tank 6 to a pressure regulating section 21 of a coating roll 2 through a pressure regulating valve 7 to form a desired crown. At the same time,
The coating film thickness measurement signal detected by the oil film measuring device 5 is fed back to the pressure regulating valve controller 71, and the pressure supply to the coating roll 2 is adjusted based on this feedback signal, thereby correcting the crown shape.

In the configuration shown in FIG. 1, it is assumed that the oil film measuring device 5 has now detected a coating film thickness state as shown in FIG.

It is known from experience that this condition is caused by a convex crown condition as shown by the solid line in FIG. Therefore, in order to correct this, it is necessary to apply the coating thicker at the center and thinner at the edges. Pressure adjustment is performed on the coating roll 2 to give it a concave crown tendency as shown by the dashed line in FIG. 5, and the pressure adjustment section 21A is operated. Therefore, the shape of the gap formed between the steel plate S and the coating roll 2 changes, and the tendency of the coating distribution also changes, correcting the coating thickness state as shown in FIG. 6.

In the method of the present invention, the viscosity of the solid lubricant solution is set to 10 to 350 seconds in Ford cup value, and the application speed is set to 1 to 150 seconds.
It is desirable to set it in the range of m/min. Further, the VC roll according to the present invention may be used as either a coating roll or a doctor roll, or may be used as both.

Note that when rubber is used as the material for the coating roll, the most effective rubber hardness is 5H40 to 100°.

When lubricant is applied to the surface of a steel plate by the method of the present invention, the coating thickness distribution is as shown in FIG. 6, for example, as shown in the target thickness (
t) 1μ, the center portion (tl) is 0.9μ and the edge portion (t2) is 1.2μ, which shows that the uniformity is extremely high. Further, according to the method of the present invention, the film thickness can be easily adjusted, and the work efficiency is significantly improved, and the coating film thickness becomes uniform, which is extremely effective in reducing the unit consumption.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing the overall configuration of the method of the present invention. FIG. 2 is a cross-sectional view showing the coating thickness distribution according to the conventional method. FIG. 6 is a drawing similar to FIG. 2 obtained by the method of the present invention. FIG. 4 is a schematic cross-sectional view of the roll structure used in the method of the present invention. FIG. 5 is an explanatory diagram showing the relationship between roll crown and coating film thickness. 1: )” Phthalol 2: Coating roll 3: Nozzle 4: Lubricant tank 5: Oil film measuring device 7: Pressure regulating valve S: Steel plate O: Oil film Patent applicant Sumitomo Metal Industries, Ltd. Figure 2 Figure 3 440

Claims (1)

[Claims] In a method of applying lubricant to a steel plate using a combination of a doctor roll and a coating roll, the roll crown of at least one of the doctor roll and the coating roll is variably formed by a pressure adjustment mechanism, and after applying the lubricant, A method for applying a lubricant to a steel plate, comprising measuring the distribution of oil film thickness in the width direction of the steel plate, correcting the roll crown amount by the pressure adjustment mechanism based on the measurement result, and applying the lubricant.