JPH07815B2 - Coil cooling convection plate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coil cooling convection plate used in an up-end type coil rust preventive cooling process.

[Conventional technology]

The coil after batch annealing uses a nitrogen atmosphere,
It is cooled in the inner cover. When the coil is cooled to about 100 ° C, rust does not occur on the coil, so the coil is taken out from the inner cover, and the involute curve-shaped groove or radial groove as shown in FIG. A convection plate (13) for cooling a coil having a cooling air circulation groove (23) that spreads toward the inner part is used for transshipment, and the atmosphere is cooled to about 40 ° C.

[Problems to be solved by the invention]

However, when the coil that has been subjected to the above-mentioned treatment is unwound during temper rolling, it often slips between the contact surfaces of the steel strips and causes scratches on the surface of the steel strip on the inner diameter side.

The present invention was devised in view of the above problems, and the mechanism of such a defect generation 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. It is something to do.

[Means for solving problems]

The coil cooling convection plate of the present invention used in the coil rust-proof cooling process of the up-end system has an air circulation obstruction plate on the coil contact surface side that obstructs the circulation of cooling air to the radial inner diameter side of the upper and lower surfaces of the coil. The basic feature is that it is provided.

Hereinafter, the process of inventing the constitution of the present invention will be described together with the research progress when the mechanism of the occurrence of scratches on the surface of the steel strip as described above was investigated and investigated.

As described above, it is obvious from the state that the scratches on the surface of the steel strip are caused by the slip between the steel strip contact surfaces of the coil. It was unclear why such a slip would occur even in a tightly wound coil.

Various studies have been conducted on the cause of such slip occurrence, but the most direct cause, which can be judged from the state of scratches, is the uneven temperature distribution in the coil during the annealing / cooling process. Was to be.

That is, as shown in FIG. 5, the temperature distribution in the radial direction inside the coil at the end of cooling the atmosphere falls while centering on the so-called hot point, especially showing a gentle downward curve toward the inner diameter side. is doing. Further, as shown in FIG. 6, the inter-coil surface pressure in the coil radial direction is highest at the hot point, and becomes lower as it goes away from the hot point, and is almost zero in a wide range on the inner diameter side. this is,
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 due to thermal contraction in the inner diameter side portion.

When the reduction of the surface pressure between the coil layers is remarkable, a fine gap is generated in the inner diameter side portion. FIG. 7 is a graph showing the measurement results when the internal stress was measured at a plurality of points in the radial direction of the coil by changing the cooling time after the batch annealing. In the inner diameter portion, it is almost 0 over a considerable range. this is,
There is nothing but a gap in the inner diameter side.

When the mandrel on the temper rolling mill entrance side is inserted into the center of the coil with such a gap formed, a gap (11) on the inner diameter side as shown in FIG.
1) accumulates at the bottom. Then, when temper rolling starts and unwinding of the coil (101) progresses to the inner diameter side part, slip occurs between the steel strip contact surfaces on the outermost peripheral side above the coil (101) so as to reduce the outermost gap (111). However, the steel strip is pulled out.

If such a condition is the cause of slip occurrence,
This is also consistent with the fact that the scratched areas are concentrated on the surface of the steel strip on the inner diameter side of the coil (101).

Therefore, the inventors of the present invention have devised the present invention in which the coil cooling convection plate used during cooling after annealing has the above-described structure in order to eliminate the temperature gradient generated in the coil during the annealing and cooling processes. It came to.

[Action]

If the convection plate for coil cooling provided with the above-mentioned air circulation obstruction plate on the coil contact surface side is used in the coil rust cooling process of the up-end method after coil annealing, the air circulation obstruction plate will be the radial direction of the coil upper and lower surfaces. The flow of cooling air to the inner diameter portion side is obstructed, and the cooling rate on the coil inner diameter portion side can be made smaller than that on the coil outer diameter portion side. Therefore, overcooling on the inner diameter side is prevented, and the temperature distribution in the coil after cooling is made uniform.

〔Example〕

 Specific examples of the present invention will be described below.

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

The convection plate has involute curved grooves (20a) (20b).
The main body (10) is a disk with a large number of
Air flow obstruction plates (30a) (30b) are further provided on both sides of the coil contact surface of the main body (10).

The air flow obstruction plates (30a) (30b) are composed of annular flat plates of a size that covers the radial inner diameter side of the upper and lower surfaces of the coils (100a) (100b) that come into contact with each other as shown in FIG. Therefore, when cooling the coils (100a) and (100b), the flow of cooling air to the inner diameter side is blocked. The size of the air flow obstruction plates (30a) (30b) varies depending on the diameter of the coils (100a) (100b) to be cooled, their winding tension, the shape of the convection plate, and the like. This is because the so-called hot point is located about 2/3 of the coil radius from the center, and therefore the position of the hot point shifts if the diameter of the coil is different. The air flow obstruction plate (30
The size of a) (30b) should be up to the position where the outer peripheral portion reaches the hot point at the maximum, and the thickness thereof should be about 0.1 to 0.5 mm.

FIG. 2 shows another embodiment of the convection plate of the present invention. The structure of the convection plate body (11) is the same as that of the first embodiment, but the air flow obstruction plate (31) attached to the coil contact surface side thereof.
Is composed of an annular mesh having a size that covers the radially inner portion of the coil upper and lower surfaces. Therefore, the air resistance in the portion of the air circulation obstruction plate (31) becomes high, and the circulation of the cooling air to the inner diameter portion side is obstructed when the coil is cooled. In this embodiment, air resistance can be adjusted by changing the size and type of mesh or by stacking a plurality of meshes according to the situation, and it becomes easier to control the temperature distribution in the coil.

FIG. 3 (a) is a cut-away perspective view showing still another embodiment, but the convection plate body (12) has involute curved grooves (22a) (22b) as in the previous two embodiments. The air flow obstruction plate (32
a) (32b) is installed. This air flow obstruction plate (32a) (32b) is different from the previous two embodiments in that the convection plate body (1
Although it is composed of an annular flat plate that covers both sides of 2), it has a large number of openings (40) on the surface that increase in diameter from the center to the outer periphery, forming a honeycomb shape as a whole. Is presenting.

In this way, by changing the diameter of the holes (40) formed in the surfaces of the air flow obstruction plates (32a) (32b) in the radial direction, the cooling air to the coil inner diameter side can be cooled during coil cooling. The distribution can be obstructed, and as a result, the temperature distribution inside the coil can be made uniform. Further, the cooling rate can be easily controlled by changing the opening ratio per unit area of the air flow obstruction plates (32a) (32b).

3 (b) and 3 (c) are plan views each showing the configuration of a coil cooling convection plate according to another embodiment manufactured in accordance with the same concept, and in the drawing, the air flow obstruction plate (33). Only (34) is shown, but the other structure is exactly the same as the previous embodiment.

In the configuration shown in FIG. 2B, the diameter of the opening (41) on the surface of the air circulation obstruction plate (33) gradually increases in the range from the center to the position corresponding to the hot point of the coil, and The diameter is gradually reduced in the range from the position corresponding to the point to the outer peripheral portion. With this configuration, it is possible to prevent overcooling of the coil inner diameter portion side and perform concentrated cooling of the hot point portion, so that the temperature distribution inside the coil can be made more uniform.

Further, in the configuration of FIG. 7C, the openings (42) on the surface of the air flow obstruction plate (34) are provided only at the positions corresponding to the hot points of the coil, preventing overcooling of the coil inner diameter side and hot. Centralized cooling of the point portion can be achieved, and the temperature gradient in the radial direction inside the coil can be eliminated.

〔The invention's effect〕

As described above in detail, when the coil cooling convection plate of the present invention is used to perform atmospheric cooling after coil annealing, the cooling rate on the coil inner diameter side is made smaller than that on the coil outer diameter side. Therefore, the temperature gradient in the radial direction inside the coil is reduced, the inter-layer surface pressure of the coil on the inner diameter side of the coil is increased, and slips are not generated during the rewinding work of the temper rolling mill. Therefore, the surface of the product is hardly scratched.

[Brief description of drawings]

FIG. 1 (a) is a plan view of a coil cooling convection plate according to an embodiment of the present invention, and FIG. 1 (b) is a longitudinal sectional view showing a state where the convection plate of this embodiment is used for cooling the atmosphere of the coil. 2 is a plan view of a convection plate for cooling a coil according to another embodiment, and FIG. 3 (a) is a perspective view showing a convection plate by cutting a part of a convection plate according to still another embodiment of the present invention. FIG. 2B is a plan view showing another embodiment, and FIG. 3C is a plan view showing another embodiment.
FIG. 4 is a plan view showing the structure 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 atmospheric cooling, and FIG. 6 is the same coil at the end of atmospheric cooling. FIG. 7 is a graph showing the coil interlaminar surface pressure in the inner radial direction, FIG. 7 is a graph showing the internal stress measurement result in the inner radial direction of the coil at the end of atmospheric cooling, and FIG. 8 is a temper rolling mill with a gap. FIG. 6 is an explanatory view showing a state of a coil attached to the mandrel of FIG. In the figure, (10), (11) and (12) are convection plate bodies, and (20a) (20
b) (21) (22a) (22b) (23) are cooling air circulation grooves, (3
0a) (30b) (31) (32a) (32b) (33) (34) are air flow obstruction plates, (40) (41) (42) are open holes, (100a) (10
Reference numerals 0b) and (101) represent coils.

Claims (3)

[Claims] 1. A convection plate for cooling a coil used in an up-end type coil anticorrosion cooling process, wherein an air circulation obstruction plate that obstructs the circulation of cooling air to the radially inner side of the upper and lower surfaces of the coil is provided on the coil contact surface. A convection plate for cooling a coil, which is provided on the side. 2. A convection plate for cooling a coil according to the above item,
The air circulation obstruction plate is composed of an annular flat plate having a size that covers the inner diameter side of the upper and lower surfaces of the coil in the radial direction.
A convection plate for cooling a coil according to the item. 3. The coil cooling convection plate according to claim 1, wherein the air flow obstruction plate is formed of an annular mesh having a size that covers the radially inner side of the upper and lower surfaces of the coil. A convection plate for cooling a coil according to claim 1.