JP3034148B2 - Liquid drawing method for steel strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the cleaning of steel strip,
When a liquid such as pickling or chemical conversion treatment is subjected to liquid drawing using a ringer roll, a method for liquid drawing of a steel strip which produces a steel strip having little pattern of roll drawing, especially with less generation of abrasion powder of the roll. It is about.

[0002]

2. Description of the Related Art In a manufacturing process of a steel strip, a large number of treatments using an aqueous solution or a fat and oil solution such as washing, pickling, and chemical conversion are performed. In this case, the liquid used at the end of each process is prevented from being taken out to the next process,
Or, in order to control the constant adhesion of the liquid used, it is common to squeeze with a roll. These rolls are generally called ringer rolls, and press the rolls from the front and back surfaces of the steel strip to narrow the gap between the roll and the steel strip, thereby controlling liquid squeezing and adhesion. These ringer rolls are generally made of a relatively soft material so as not to damage the steel strip. For example, they are made of rubber or resin such as chloroprene, chlorosulfonated polyethylene, urethane or polybutadiene.

In addition, these ringer rolls are often rotated at the same speed in accordance with the direction in which the steel strip passes in order to prevent flaws on the steel strip and minimize the wear of the roll. However, these rubber and resin ringer rolls are liable to deteriorate in surface due to the properties of the liquid used, frictional heat due to use, and other environments. When the steel strip is squeezed more than a certain extent, wear powder is generated on the surface. These abrasion powders bring about uneven squeezing of the liquid, and further, the abrasion powders adhere to the steel strip, causing significant deterioration in the surface appearance of the product. Further, if the wear of these ringer rolls occurs in a short period of time, the processes cannot be continuously performed, and the rolls must be replaced, resulting in a great loss in production.

[0004] From the above viewpoint, it is an important subject to perform liquid squeezing by a ringer roll for a long period without generating abrasion powder.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a method for reducing the amount of powder produced by roll abrasion when rolling a liquid such as washing, pickling and chemical conversion treatment of a steel strip using a ringer roll. It is an object of the present invention to provide a method for producing a belt stably.

[0006]

Means for Solving the Problems The present inventors worked on various investigations and experiments on liquid squeezing by using rolls of steel strip.
As a result of intensive studies, the present inventors have found an appropriate range in which the generation of abrasion powder of the roll can be suppressed particularly between the rotation speed of the roll and the passing speed of the steel strip, and have completed the present invention.

That is, according to the present invention, when a pair of ringer rolls are pressed from the front and back surfaces of a steel strip to squeeze liquid adhering to the surface of the steel strip by washing, pickling, chemical conversion or the like, the radius of the roll is set to r (mm). When the roll crush width (nip width) when the roll is pressed against the steel strip is d (mm), the roll rotation speed V
(mpm) and the passing speed L (mpm) satisfy the following expression.

{R ² − (d / 2) ² } /r−0.0015≦V/L <1.0

[0009]

The ringer roll uses a relatively soft rubber or resin roll as described above, but since these rolls are soft, they are locally crushed when pressed when squeezing the liquid in the steel strip. Contact steel strip with width. This state is shown in FIG. 1, the surface pressure f _CE of the steel strip 2 and the roll 1 of the central portion of the nip width 3 becomes highest state in a state having a certain nip width 3. Further, in the portion of the roll having a large diameter in the body length direction, the amount of deviation of the roll is larger than in other portions, so that the surface pressure in the central portion of the nip width is further increased. In this state, the roll is rotated in the sheet passing direction of the steel strip. When the ratio (V / L) of the rotation speed V of the roll to the sheet passing speed L at this time is 1.0, the roll is shown in FIG. As described above, the difference between the speed of the steel strip and the speed of the roll at the nip portion is largest at the center portion of the nip width, the amount of rubbing at the portion where the surface pressure is highest is large, and the generation of wear powder increases.

At this time, the speed ratio (V / L) = √ ｛r ²
In the state of − (d / 2) ² ｝ / r, as shown in FIG. 3, the speed difference between the steel strip and the roll is 0 at the center of the nip width where the surface pressure is highest, that is, the rubbing amount is small. It is completely eliminated and the generation of wear powder is reduced. Hereinafter, the reason for the production method regulated in the present invention will be described.

FIG. 4 shows the amount of abrasion powder generated from the rubber roll with respect to the speed ratio (V / L). This is done by passing a strip through a line having a ringer roll and actually pressing the ringer roll to generate rubber powder, and a passing speed L = 10
The weight of rubber powder generated after operation at 0 mpm for 10 hours was measured. As the material of the ringer roll, a material obtained by winding chlorosulfonated polyethylene around a metal roll was used. The radius of the roll at this time was 175 mm, and the nip width when pressing the roll was 25 mm.

As can be seen from FIG. 4, when (V / L) is 1.0 or more, the weight of the generated rubber powder is clearly large, and (V / L) = {r ² − (d / 2) ² }. / R in the vicinity. Further, (V / L) = √ ｛r ² − (d
/ 2) The amount of rubber powder is small up to ² ｝ /r-0.0015, and where it is smaller, the amount of generated rubber powder is large.

As described above, when the speed ratio (V / L) is Δr
^{In the range of 2-} (d / 2) ² ｝ / r-0.0015 ≤ (V / L) <1.0, the generation of rubber powder is small, and the generation of squeezing patterns harmful to products in liquid squeezing is used for a long time. Can be prevented.

[0014]

Examples are shown in Table 1. This time, chromic acid treatment was performed as the treatment using the liquid of the steel strip, but this treatment may be another chemical conversion treatment, or the same applies to other treatments such as washing and pickling. One of the ringer rolls used was a chlorosulfonated polyethylene resin wound around a metal roll. The roll had a radius r of 175 mm and was pressed against a steel strip with a load of 500 kgf. The nip width at that time was 25 mm. Further, a chloroprene rubber wound around a metal roll was used. The roll had a radius r of 165 mm and was pressed against a steel strip with a load of 450 kgf. The nip width at that time was 20 mm, but similar results were obtained with the roll material, thickness, radius, pressing force, and nip width of the two or more examples. As an evaluation of stable production, the running length (km) of a steel strip until the roll drawing pattern was generated due to the generation of roll wear powder was measured.

Thus, according to Table 1, the ratio (V / L) between the roll rotation speed and the passing speed is expressed as {r ² − (d / 2) ² } /
By setting r−0.0015 ≦ V / L <1.0, it is possible to significantly increase the length of the thread passing until the roll drawing pattern is generated.

[0016]

[Table 1]

[0017]

Thus, according to the present invention, cleaning of a steel strip,
In the case of performing liquid squeezing of a roll when using a liquid such as pickling or a chemical conversion treatment, it is possible to stably produce a steel strip having little roll abrasion powder and having no roll squeezed pattern.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a surface pressure distribution when a ringer roll is pressed.

FIG. 2 is a schematic diagram of a speed difference between a steel strip and a roll at a nip portion when V / L = 1.0.

FIG. 3 is a schematic diagram of a speed difference between a steel strip and a roll at a nip portion when V / L = {r ² − (d / 2) ² } / r.

FIG. 4 is a graph showing a relationship between a speed ratio (V / L) and an amount of generated wear powder (rubber powder).

[Explanation of symbols]

 1 Ringer roll cross section 2 Steel strip 3 Nip width (d) 4 Roll radius (r) fi Surface pressure Vi Speed difference V Roll rotation speed L Passing speed

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23G 3/02

Claims (1)

(57) [Claims] When a pair of ringer rolls are pressed from the front and back surfaces of a steel strip to squeeze liquid adhering to the surface of the steel strip by washing, pickling, chemical conversion, or the like, the radius of the roll is set to r (mm) and the roll is rolled. The crush width (nip width) of the roll when pressed against a steel strip is d (m
m), the roll rotation speed V (mpm) and the passing speed L
A liquid drawing method for a steel strip, wherein the ratio to (mpm) satisfies the following expression. {R ² − (d / 2) ² } /r−0.0015≦V/L <1.0