JPH01230726A - Convection plate for cooling coil - Google Patents

Abstract

PURPOSE:To uniformize temp. distribution in a coil after cooling and to enable manufacture of the coil having good quality by arranging an air flowing baffle plates for cooling at contacting face side with the coil and also constituting the main body with the specific construction of convection plate for cooling. CONSTITUTION:Excess cooling to an inner radius side of the coils 100a, 100b is prevented by constituting with arranging involute curve-like grooves 20a, 20b on the surface of the convection plate main body 10 and arranging the air flowing baffle plates 30a, 30b for cooling at inside of inside of the contacting face with the coil. By this method, the temp. distribution in the coil after cooling is uniformized and the coil having good quantity without any fault on the product surface can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coil cooling convection plate used in an up-end type coil rust prevention cooling process.

[Conventional technology]

Coils that have undergone patch annealing are treated in a nitrogen atmosphere.
Cooled inside the inner cover. When the coil is cooled to about 100°C, there will be no rust, so it is removed from the inner cover and cut into grooves from the center to the periphery, such as involute curved grooves or radial grooves as shown in Figure 4. The coil cooling convection plate (13) having cooling air circulation grooves (23) expanding toward the
It is atmospherically cooled to ℃.

[Problem that the invention seeks to solve]

However, when a coil that has been subjected to the above-described treatment is unwound during temper rolling, slipping occurs between the contact surfaces of the steel strip, often causing scratches on the surface of the copper strip on the inner diameter side.

The present invention was devised in view of the above-mentioned problems, and the mechanism of such flaw occurrence was investigated and studied, and as a result, the structure of the coil cooling convection plate used in the coil rust prevention cooling process was improved. This is what I am trying to do.

[Means for solving problems]

The coil cooling convection plate of the present invention used in the up-end type coil rust-preventing cooling process has an air flow inhibiting plate on the coil contact surface side that inhibits the flow of cooling air toward the radially inner diameter portion of the upper and lower surfaces of the coil. The basic feature is that

Hereinafter, the circumstances that led to the creation of the configuration of the present invention will be explained along with the progress of the research conducted when the mechanism of scratch formation occurring on the surface of the copper strip as described above was investigated and examined.

As mentioned above, it is easy to see that scratches on the surface of the steel strip are caused by slipping between the contact surfaces of the copper strip of the coil, but the cause of the slip, namely It was unclear why such slippage occurs even in tightly wound coils.

Various reasons have been investigated for the occurrence of such slips, but judging from the condition of the scratches, the most direct cause is thought to be due to uneven temperature distribution within the coil during the annealing and cooling process. It was intended to be.

In other words, the temperature distribution in the radial direction inside the coil at the end of atmospheric cooling shows a downward curve with the so-called hot point at the center and toward the inner diameter, as shown in Figure 5. However, it is descending. Further, as shown in FIG. 6, the coil interlayer contact pressure in the inner radial direction of the coil is highest at the hot point, and decreases as the distance from the hot point increases, reaching approximately 0 in a wide range on the inner diameter side. This is because the temperature distribution in the radial direction of the coil is non-uniform as described above, so that the surface pressure between the coil layers decreases in the inner diameter portion due to thermal contraction.

If such a reduction in surface pressure between the coil layers is significant, a minute gap will occur at the inner diameter side portion. Figure 7 is a graph showing the measurement results when the internal stress was measured at multiple points in the radial direction inside the coil with various cooling times after patch annealing. The inner diameter portion is approximately O over a considerable range.

This is nothing but a gap created on the inner diameter side.

When the mandrel on the entrance side of the skin pass rolling machine is inserted into the center of the coil with such a gap, the coil (101)
Due to its own weight, the gap (
111) accumulates at the bottom.

Then, the skin pass rolling starts, and when the unwinding of the coil (101) progresses to the inner diameter side, between the upper and outermost copper strip contact surfaces of the coil (101) so as to reduce the outermost gap (111). The steel strip will be pulled out while it slips.

If this condition is the cause of slippage,
This also coincides with the fact that scratches are concentrated on the surface of the steel strip on the inner diameter side of the coil (101).

Therefore, in order to eliminate the temperature gradient that occurs within the coil during the annealing and cooling process, the present inventors have developed the present invention in which the coil cooling convection plate used during cooling after annealing has the above-described structure. This is what I came up with.

[For production]

If a coil cooling convection plate with the above-mentioned air flow inhibiting plate provided on the coil contact surface side is used in the up-end type coil rust prevention cooling process after coil annealing, the air flow inhibiting plate will be installed in the radial direction of the upper and lower surfaces of the coil. This obstructs the flow of cooling air toward the inner diameter portion, making it possible to make the cooling rate on the inner diameter portion of the coil smaller than that on the outer diameter portion of the coil. Therefore, overcooling of the inner diameter side is prevented, and the temperature distribution inside the coil after cooling is made uniform.

〔Example〕

Specific examples of the present invention will be described below.

FIGS. 1(a) and 1(b) show a coil cooling convection plate according to an embodiment of the present invention and its usage state.

The convection plate has an involume 1 curved groove (20a) (
20b) on its surface, its main body (l
The main body (io) further includes air flow inhibiting plates (30a) (30b) on both sides of the coil contact surface.

The air flow inhibiting plates (30a) (30b) are shown in FIG.
) as shown in the contacting coil (100a) (looo
b) The coil (100a) (10
0b) It obstructs the flow of cooling air toward the inner diameter portion during cooling. This air circulation inhibiting plate (30a) (30
The size of b) is the coil (100a) to be cooled (
100b), their winding tension, the shape of the convection plate, etc. This is because the so-called hot point is located approximately 2/3 of the coil radius from the center.
This is because if the diameter of the coil differs, the position of the hot point will also shift. Note that the air flow inhibiting plate (30a) of this example
) (30b) should have a maximum size up to the point where the outer periphery reaches the hot point, and its thickness should be 0.1 to 0.
, 5 nwn or so.

FIG. 2 shows another embodiment of the convection plate of the present invention. The configuration of the convection plate main body (11) is the same as the first embodiment, but
An air flow prevention plate (3) attached to the coil contact surface side
1) is composed of an annular mesh having a size that covers the radially inner diameter portion of the upper and lower surfaces of the coil. Therefore, the air resistance at the air flow inhibiting plate (31) increases, and the flow of cooling air toward the inner diameter portion of the coil is inhibited during cooling of the coil. In this embodiment, air resistance can be adjusted by changing the size and type of the mesh or stacking multiple meshes depending on the situation, making it easier to control the temperature distribution inside the coil.

FIG. 3(a) is a cutaway perspective view showing still another embodiment, in which the convection plate main body (12) has involute curved grooves (22a) (22b) as in the previous two embodiments. and air flow inhibiting plates (32a) (32b) are attached to sandwich it from both sides. These air circulation inhibiting plates (32a) (32b), unlike the second embodiment, are composed of annular flat plates that respectively cover the entire both sides of the convection plate main body (12). A large number of apertures (40) are provided, the diameter of which becomes larger towards the end, and the whole has a honeycomb shape.

By changing the diameter of the openings (40) formed on the surfaces of the air flow inhibiting plates (32a) (32b) in the radial direction, cooling air can be directed toward the inner diameter portion of the coil when cooling the coil. The flow is obstructed, and as a result, the temperature distribution inside the coil can be made uniform. In addition, these cooling rates can be controlled by using an air flow inhibiting plate (32a).
This can be easily achieved by changing the opening ratio per unit area of (23b).

FIGS. 3(b) and 3(c) are plan views respectively showing the configuration of a coil cooling convection plate according to another embodiment manufactured based on the same purpose. (3
Although only 4) is illustrated, the other configurations are exactly the same as the previous embodiment.

In the configuration shown in FIG. 6(b), the diameter of the opening (41) on the surface of the air flow inhibiting plate (33) gradually increases in the range from the center to the position corresponding to the hot point of the coil. The diameter is gradually tapered in the range from the point equivalent position to the outer periphery. In this way, it is possible to prevent overcooling of the inner diameter portion of the coil and to concentrate cooling on the hot point portion, thereby further increasing the uniformity of the temperature distribution within the coil.

Furthermore, in the configuration shown in Figure (C), the openings (42) on the surface of the air flow inhibiting plate (34) are provided only at positions corresponding to the hot points of the coil, which prevents overcooling and prevents hot spots on the inner diameter side of the coil. It is possible to achieve concentrated cooling at the point and eliminate temperature gradients in the radial direction inside the coil.

〔Effect of the invention〕

As detailed above, when the coil cooling convection plate of the present invention is used to perform air cooling after coil annealing, the cooling rate on the inner diameter side of the coil can be made smaller than that on the outer diameter side of the coil. As a result, the temperature gradient in the radial direction inside the coil decreases, and the surface pressure between the coil layers on the inner radial side of the coil increases, eliminating the occurrence of slip during the unwinding operation of the skin pass rolling mill. Therefore, there are almost no scratches on the product surface.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view of a convection plate for cooling a coil according to an embodiment of the present invention, and FIG. 1(b) is a longitudinal cross-sectional view showing a state in which the convection plate of this embodiment is used for atmospheric cooling of a coil. , FIG. 2 is a plan view of a coil cooling convection plate according to another embodiment, and FIG. 3 (
a) is a partially cutaway perspective view of a convection plate showing still another embodiment of the present invention, figure (b) is a plan view showing another embodiment, and figure (c) is still another embodiment. A plan view showing the embodiment; FIG. 4 is a plan view showing the configuration of a conventional coil cooling convection plate;
Fig. 5 is a graph showing the temperature distribution in the radial direction inside the coil at the end of air cooling, Fig. 6 is a graph showing the coil interlayer contact pressure in the radial direction inside the coil at the end of air cooling, and Fig. 7 is the same. FIG. 8 is a graph showing the measurement results of the internal stress in the radial direction of the coil at the end of atmospheric cooling, and is an explanatory drawing showing the state of the coil placed on the mandrel of the skin pass rolling mill with a gap formed. In the figure, (to) (11) (12) is the convection plate main body, (
20a) (20b) (21) (22a) (22b
) (23) are cooling air distribution grooves, (30a) (30b
) (31) (32a) (32b) (33) (
34) is an air flow prevention plate, (40) (41) (42)
(100a), (100b), and (101) indicate the coils. Figure 1 (a) Figure 1 Figure 4 Figure 5 Figure 6 Figure 7

Claims (3)

[Claims] (1) In the coil cooling convection plate used in the up-end coil rust-preventing cooling process, an air flow inhibiting plate is placed on the coil contact surface side to inhibit the flow of cooling air to the radially inner diameter portion of the upper and lower surfaces of the coil. A convection plate for coil cooling characterized by being provided with a coil cooling convection plate. (2) In the coil cooling convection plate described in the preceding paragraph, the air flow inhibiting plate is constituted by an annular flat plate having a size that covers the radially inner diameter side of the upper and lower surfaces of the coil. convection plate. (3) In the coil cooling convection plate according to claim 1, the air flow inhibiting plate is formed of an annular mesh having a size that covers the radially inner diameter side of the upper and lower surfaces of the coil. The coil cooling convection plate according to item 1.