JPH04107221A - Device for cooling strip in continuous annealing furnace - Google Patents

Abstract

PURPOSE:To shorten the cooling time of strip by constituting this strip cooling device in a continuous annealing furnace with a cooling roll, small mobile rolls constituted movably on the locus of concentric circle with the cooling roll and deflector rolls. CONSTITUTION:The stip cooling device is constituted of the cooling roll 1, two small shifting rolls 3 integrally with the cooling roll 1 winding the strip 2 on the cooling roll 1 and constituted movably on the locus of concentric circle with the cooling roll 1 to the center of rotary axis and the deflector rolls 4, 5 set in front and rear of the cooling roll 1. By shifting the shifting rolls 3 on the locus of concentric circle with the cooling roll 1, since contact angle theta of the strip to the cooling roll 1 is made to vary from near 360 deg. to 10 deg., the cooling capacity per one piece is increased and the cooling time can considerably be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a strip cooling device in a continuous annealing furnace that can make the contact angle of the strip in contact with a cooling roll to 180 degrees or more.

[Prior Art] In a strip cooling device that cools a strip by winding it around a plurality of cooling rolls arranged horizontally or vertically, when the cooling load is large as shown in Fig. 3 (a), a deflector is used. - Cooling is performed by wrapping the strip 24 around a number of cooling rolls 23 arranged between the rolls 21 and 22, and when the cooling load is small,
As shown in FIG. 3(b), some of the cooling rolls 23a are moved back so that the strips 24 do not come into contact with each other, or the contact angle (θ>) of the rolls is changed. Then, since the strips 24 are not in contact with the cooling rolls 23 between adjacent cooling rolls 23, the cooling rate decreases between them, and it takes longer to cool to a predetermined temperature than when cooling is possible continuously. It takes time.

FIG. 4 is a graph comparing the temperature history of the strip when the strip 24 is cooled by the strip cooling device and the temperature history when the strip is continuously cooled at the same cooling rate at the cooling roll 23. The strip cooling device uses five cooling rolls 23, but the time during which the strip is not cooled between the cooling rolls 23 (
Because of 1), it takes time T to cool down to a predetermined temperature compared to the case where continuous cooling is assumed.

[Problem to be Solved by the Invention] Therefore, in order to shorten the cooling time of the strip, it is necessary to increase the contact angle of the strip to the cooling roll (θ in Fig. 3) and to increase the diameter of the cooling roll. However, since the contact angle can conventionally be adjusted only by moving the cooling roll up and down, there is a problem in that the contact angle can only be adjusted to a maximum of about 180 degrees.

This invention solves the above-mentioned problems of the prior art,
In a continuous annealing furnace, the contact angle can be made 180 degrees or more, so the cooling efficiency per cooling roll is high, and if the roll diameter is increased, continuous cooling is possible from the start of cooling to the end of cooling. The purpose is to provide a strip cooling device.

[Means for Solving the Problems] A strip cooling device for a continuous annealing furnace according to the present invention includes a cooling roll, the strip is wound around the cooling roll integrally with the cooling roll, and the center of the rotating shaft is aligned with the cooling roll. This strip cooling device in a continuous annealing furnace is comprised of a moving roll movable on a concentric trajectory and having a smaller roll diameter than the cooling roll, and deflector rolls arranged before and after the cooling roll.

[Function] The strip cooling device for a continuous annealing furnace according to the present invention includes a cooling roll, a strip knob that is integrally wound around the cooling roll, and a center of the rotating shaft on a trajectory concentric with the cooling roll. The cooling roll is composed of a movable roll having a diameter smaller than that of the cooling roll, and deflector rolls arranged before and after the cooling roll. By moving the movable roll on a trajectory concentric with the cooling roll, the contact angle of the strip with the cooling roll can be varied from 0 to 360.
Since the cooling capacity can be changed by stopping at around 100°C, the cooling capacity per roll is larger than that of conventional cooling rolls.If the diameter of the cooling roll is increased, one cooling roll is required from the start of cooling to the end of cooling. It can be cooled continuously and the cooling time can be significantly shortened.

[Embodiment] A strip cooling device in a continuous annealing furnace according to a first embodiment of the present invention will be explained with reference to FIG. FIG. 1 is an explanatory side view of a strip cooling device according to a first embodiment of the present invention. A strip cooling device in a continuous annealing furnace according to a first embodiment of the present invention includes a cooling roll 1, and a strip 2 integrated with the cooling roll l.
a moving roll 3, which is wound around the cooling roll 1 and configured to be able to move on a trajectory whose rotating shaft center is concentric with the cooling roll 1, and whose diameter is smaller than that of the cooling roll 1; and a deflector disposed before and after the cooling roll 1. - consists of rolls 4 and 5. By moving the movable roll 3 on a trajectory concentric with the cooling roll 1, the contact angle θ of the strip 2 with respect to the cooling roll 1 is adjusted to around 360 degrees as shown in FIG. 1(a). Stop Figure 1 (
Since it is possible to change it up to 0 as shown in b),
The cooling capacity per cooling roll is larger than that of conventional cooling rolls, and by increasing the diameter of the cooling roll, continuous cooling can be performed with one cooling roll from the start of cooling to the end of cooling, significantly reducing the cooling time. can be shortened to

FIG. 2 is an explanatory side view of a strip cooling device according to a second embodiment of the present invention. In this example, the strip 2 is transferred to the cooling roll 1 integrally with the cold red roll 11.
A moving roll 12 is wound around the cooling roll 1 and is configured such that the center of its rotating shaft can move on a trajectory concentric with the cooling roll 11.
In the case of a book, the arrangement of the deflector rolls 4 and 15 before and after the cooling roll 11 is also different from that of the first embodiment. Also in the case of the second embodiment, since the contact angle θ can be set to 180 degrees or more, the cooling capacity per cooling roll can be increased.

Next, consider the contact angle θ of the cooling roll and the radius R of the cooling roll.
We will explain how to determine. The amount of heat transfer per unit time is Q (Kd/h), the temperature of the cooling roll and the temperature of the strip (°C) are respectively tr + tll - the contact area of the strip with the cooling roll (m2) is S, and the heat transfer coefficient (
If KcaQ/m"・h・"C)) is α, then Q=α(ts-tr)S...(1) The radius of the cooling roll (m) is R, the width of the strip (m) is W, If the contact angle (degrees) of the strip to the cooling roll is θ, then S=2πRWθ/360...(21 Therefore, Q-α(t,-tr)・2πRWθ/360-[31
On the other hand, if the line speed (m/layer in) of the strip is V, then the cooling amount per unit area of the strip is q
(Kcal/m”) is Q=Q/60vW =α(t, -t,)・πRθ/10800v −=I
The thickness of the 4J strip (1 tone) is t, and the specific heat of the steel (Km/kg・℃) is the temperature of the C5 strip after cooling, t.

Then, the required cooling amount per unit area of the strip q
. (Kcd / m2) is Qo = 7.85tc (ts - jso) ・(
(5) Therefore, from equations (4) and (5), q-Q.

As follows, R and θ of the cooling roll in the case of continuous cooling with one cooling roll can be determined.

That is, α(ts tr) ・πRθ/10800v=7.8
5tc (ts -t,o)Rθ-10800X7.8
5tcv(t, -t,o)/α(t, -tr)π2.
7X10' tcv(ta t, o)/α(t, -
L) (61 In equation (6), assuming that the specific heat C1 of the steel, the heat transfer coefficient α, is constant, and the temperature difference (ta-tr) between the temperature of the strip before cooling and the temperature of the cooling roll is constant, , Rθ is the thickness t of the strip, the line speed ■, and the temperature difference before and after cooling the strip (t-t-o)
is proportional to the product of

In addition, in the present invention, only one cooling roll with a large diameter is required, so unlike the conventional cooling roll, since the diameter of the cooling roll is small, the amount of deformation of the strip becomes large, resulting in the deformation of the strip 2 as shown in FIG. Since a phenomenon such as lifting of the end portion 2a does not occur, uneven cooling of the strip in the width direction of the strip does not occur.

[Effects of the Invention] According to the present invention, the cooling rate of the strip can be increased.

A graph showing the temperature history when the strip is cooled by the cooling device, and FIG. 5 is a cross-sectional view showing the lifting of the strip.

1.11・Cooling roll, 3,13 Moving roll, 4.5
．． 14.15 Deflector roll.

Claims (1)

[Claims] a cooling roll; and a moving roll that is integral with the cooling roll, wraps the strip around the cooling roll, and is configured such that the center of its rotating shaft can move on a locus concentric with the cooling roll, and has a roll diameter smaller than that of the cooling roll. 1. A strip cooling device in a continuous annealing furnace, comprising: deflector rolls arranged before and after the cooling roll.