Method for cooling a metallic item and cooling bar

Abstract

The invention relates to a method for cooling a metallic item (1) by discharging a cooling medium from a cooling bar (2) onto the item (1), wherein the cooling medium is discharged through a slot (3) in the cooling bar (2). According to the invention, in order to achieve improved cooling, during the cooling process the width (B) of the slot (3) in the conveying direction (F) of the item (1) or of the cooling bar (2) is altered in order to bring the cooling power of the cooling medium to a desired or predefined level by open-loop or closed-loop control. In addition, the invention relates to a cooling bar.

Claims

1. A method for cooling a metallic item by discharging a cooling medium from a cooling bar onto the metallic item, wherein the cooling medium is discharged through a slot in the cooling bar, wherein during a cooling process a width of the slot in a conveying direction of the metallic item or of the cooling bar is altered in order to bring a cooling power of the cooling medium to a desired or predefined level by open-loop or closed-loop control, wherein the width of the slot in a direction both transverse to the conveying direction and perpendicular to an outlet direction of the cooling medium is altered differently in sections, wherein the slot is delimited by at least two sections of the cooling bar, wherein the two sections of the cooling bar, when viewed perpendicularly to the outlet direction of the cooling medium, each have a concave portion and adjoiningly thereto a convex portion, and wherein the at least two sections of the cooling bar are shifted in a direction that is both perpendicular to the outlet direction of the cooling medium and perpendicular to the conveying direction in order to alter the width of the slot.

2. The method according to claim 1, wherein the width of the slot is set so that the width is greater in a central area of the metallic item to be cooled than at lateral end areas of the metallic item to be cooled.

3. The method according to claim 1, wherein each one of the two sections of the cooling bar, when viewed perpendicularly to the outlet direction of the cooling medium, have the concave portion and the adjoiningly convex portion to define an S-shaped profile.

4. The method according to claim 1, further comprising altering the width of the slot in the first conveying direction by at least one of electrical, pneumatic and hydraulic adjustment means.

5. The method according to claim 4, wherein the adjustment means is in connection with the open-loop control, wherein at least one sensor in connection with the open-loop control is arranged, from which a physical property of the metallic item can be determined.

6. The method according to claim 4, wherein the adjustment means is an actuator in connection with the closed-loop control, wherein at least one sensor in connection with the closed-loop control is arranged, from which a physical property of the metallic item can be determined, and the at least two sections of the cooling bar are automatically adjusted by the actuator in response to signals from the at least one sensor during a rolling operation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawing, an embodiment example of the invention is represented. In the drawing:

(2) FIG. 1 diagrammatically shows the side view of a cooling bar, represented in cross section, which cools a metallic item running by in the conveying direction,

(3) FIG. 2a shows the slot of the cooling bar, when viewed in outlet direction of the cooling medium, in a first relative position of two sections of the cooling bar, and

(4) FIG. 2b shows the slot of the cooling bar according to FIG. 2a in a second shifted relative position of the sections of the cooling bar.

DETAILED DESCRIPTION OF THE INVENTION

(5) In FIG. 1, a cooling bar 2 can be seen, under which a metallic item 1 in the form of a metal strip extends in the conveying direction F and is cooled by cooling medium discharged by the cooling bar 2. The horizontal direction Q transverse to the conveying direction F is perpendicular to the plane of the drawing in FIG. 1.

(6) In a manner known per se, the cooling bar 2 has a slot 3 extending over the entire width of the metallic item 2, that is to say in the direction Q, and here—when measured in the conveying direction F—has a width B.

(7) As can be seen in FIG. 1, the outlet direction A of the cooling medium is arranged at a certain angle relative to the surface of the item 1, which, however, does not change the fact that the width B extends over a certain distance in the conveying direction F.

(8) It is essential that the slot 3 of the cooling bar 2 can be altered during the cooling process with respect to its width B, and for that purpose adjustment means 8 are provided. In FIG. 1, they are indicated only schematically and they can be of any type (electric, pneumatic, hydraulic).

(9) By means of said adjustment means, two sections 4 and 5 of the cooling bar 2 can be moved or adjusted relative to one another, i.e., one of the sections, section 5 in the embodiment example, is moved in a feed direction Z in order to set the width B of the slot 3.

(10) In FIG. 1, it is indicated that a physical variable (this can be the planarity of the item 1 or its temperature) is acquired by means of a sensor 10, and the measured value is supplied to an open-loop control 9. Said open-loop control, based on an algorithm stored in it, can then deliver a control signal to the adjustment means 8, by means of which a certain width B is set, so that a desired property of the item 1 can be achieved. Thus, in the closed control loop it can be ensured that the width B of the slot 3 of the cooling bar is set so that a desired property of the item 1 results.

(11) A special and preferred design of the sections 4 and 5 of the cooling bar 2 can be seen in FIGS. 2a and 2b.

(12) When viewed in outlet direction A of the cooling medium, which in FIGS. 2a and 2b is perpendicular to the plane of the drawing, the two sections 4, 5 have concave portions 6 and convex portions 7, so that the represented S-shaped course of the delimitation of the slot 3 results.

(13) While in FIG. 2a the two sections 4 and 5 are located in a starting position and the slot 3 here has a largely constant (albeit curved) width B, in FIG. 2b the two sections 4 and 5 are shifted relative to one another in direction Q (in FIG. 2 the upper section 4 has been shifted to the right and the lower section 5 to the left). Accordingly, the form of the slot 3 has been altered.

(14) As can be seen in FIG. 2b, in the central area of the item to be cooled, due to the larger width B of the slot 3, more cooling medium reaches the item, while in the two lateral areas of the metal sheet 1 or end areas of the slot 3, a smaller width is present and thus less cooling medium exits.

(15) By a corresponding shifting of the two sections 4 and 5 in direction Q, the quantity and the distribution of the exiting cooling medium can thus be influenced and thereby the cooling process can be controlled by open-loop or closed-loop control.

(16) In particular this occurs actively during the cooling process, so that an influence on changing circumstances with regard to the process can be obtained by influencing the cooling.

LIST OF REFERENCE NUMERALS

(17) 1 Metallic item 2 Cooling bar 3 Slot in the cooling bar 4 Section of the cooling bar 5 Section of the cooling bar 6 Concave portion 7 Convex portion 8 Adjustment means 9 Open-loop control 10 Sensor B Width of the slot F Conveying direction of the item/of the cooling bar Z Feed direction Q Direction transverse to the conveying direction A Outlet direction of the cooling medium