DE2440415A1 - METHOD AND DEVICE FOR THE CONTROLLED COOLING OF ROLLED MATERIAL, IN PARTICULAR OF BAR MATERIAL - Google Patents

Description

Method and device for the controlled cooling of rolling stock, in particular rod material.

The invention relates to a method and a device for controlled -Cooling of rolling stock, especially rod material, wherein the warm rolling stock passes through one or more cooling sections, in which the cooling water on the inlet and outlet side via nozzle heads fed in and discharged via a centrally arranged storage space that accumulates the oppositely directed cooling water flows will.

In order to achieve a certain structure formation in the rolling stock after rolling, it is known to ^{cool the rolling stock emerging from the last stand with a final rolling temperature of 900-110O 0} C in water-fed cooling sections under cooling conditions adapted to the respective structure formation. Bs is known that leaves at temperatures of 9CC to 1100 ⁰ C during hot rolling the rolling stock, in particular ITeinstahl and wire, the last stand. Processes for cooling from the rolling heat are also known, which give the rolling stock a specific structure.

A number of cooling devices are available for this purpose Construction known. 3s are double-walled Cooling tubes, the cooling water being guided from the jacket tube to the inner tube through openings of different design Rolled stock meets. On the other hand, cooling tubes are known in which

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the cooling water via flanged nozzle heads to the continuous Rolled stock is printed. In the case of such cooling pipes, the undesired enrichment of the cooling water with air is not permitted as this is sucked in through the nozzle as well as being carried away by the rolling stock. This results in a Deterioration of the cooling effect with regard to the level of the achievable heat transfer coefficient and its constancy over the Material surface with all its negative consequences for the material properties.

Bs is also a device for cooling fine steel and wire from the rolling heat known that this disadvantage of tries to counter the cooling tube principles explained by the fact that the individual cooling tubes in trough-like, filled with 7 / water Containers, are arranged. However, this arrangement has some disadvantages. Such is a discontinuous operation due to the relatively long start-up time for filling the tub-like Container not possible. In addition, the entire length of the storage takes place in the containers filled with water an expensive construction, and the setting of an increased pre-pressure in front of the nozzle head is not possible. That I the tub-like container fills with scale during operation, Changing the cooling tubes and regulating the static pressure of the cooling tubes is made considerably more difficult. Also brings the necessary removal of the scale an additional workload and a disruption of the operational sequence by the thereby associated maintenance work.

It is also known a cooling tube in which arranged by radially Pre-nozzles in the nozzle head should largely avoid sucking in air. Through this additionally in the nozzle head arranged nozzles, there is a strong increase in water consumption.

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The invention aims to avoid the disadvantages of the known method and plant and a method and an apparatus to develop with which the most diverse cooling conditions resulting from the respective rolling stock dimensions, the desired structure, the required cooling temperature and the resulting cooling rates can be guaranteed.

The invention is based on the object of developing a method and an apparatus which allows with minimal Cooling water consumption and the avoidance of air penetration into the cooling section in a simple way depending on the cooling conditions of the desired rolling stock properties over a wide range Adjust the control range reproducibly.

According to the invention this object is achieved in that in the Cooling section a cooling water pressure of greater than 0 atü, preferably 0.5-5 atm, and that the cooling water return flow is returned above the level of the cooling section, with secondary cooling water flows from the cooling water return flow be branched off with adjustable cooling water pressure, with which the rolling stock before it enters the or is applied behind the exit from the cooling section.

An advantageous application of the method provides that for high temperature thermo-mechanical treatment of rolling stock with a dimension of 10 - 16 mm around this material with a final rolling temperature of 85O - 9QO ⁰ C with a Kühlwassermange of about 100 nr / h in a cooling time of 1 , 5-2.5 seconds is cooled to a temperature of "^ 10O ⁰ C. Another variant of the process is characterized in that rolled stock with a dimension of 12 mm round and a final rolling temperature of 95O ⁰ C with a water consumption of approx nr / h is cooled ^{to 610 0} C in a cooling time of 0.5 sec.

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Another modification of the method provides that rolling with a dimension of 12 mm round and a Sndwalztemperatur of 95O ⁰ C by changing the secondary quantity of water at a water consumption of about 50 m / h in a ICühlzeit of 0.5 sec at 55O ⁰ C cooled will.

Another variant of the method provides that, in order to achieve a structure similar to normalization, in "-Valzgut with a Dimensions of 28 - 32 mm round this material with a cooling water consumption of about 60 nr / h and a cooling rate of 50 ° Ciiisek is cooled.

According to the invention, a device is provided for carrying out the method used, which is characterized in that the nozzle heads ge a water chamber with an overflow: anal upstream which is connected to the cooling water return line via a secondary line and an adjusting valve.

The device is further characterized in that the cooling water return line is designed and connected as a riser pipe the storage space is connected.

The device is further characterized in that the secondary lines are connected to the cooling water return line upstream of the discharge control valve are connected.

The device is also characterized in that the discharge control valve and the control valves are connected to a common actuator are connected.

An advantageous further development of the device provides that the water chamber has one or more vertical staggered positions arranged partition walls with axially aligned recesses for the passage of the rolling stock.

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The design according to the invention increases the cooling of the salted goods with a constant supply of fresh water. The entry of secondary cooling water into the cooling pipe is through controlled the adjustable pressure in the water chamber. The KLtrdßen ' and suction of air into the cooling pipe can be suppressed or suppressed in a defined manner.

There is no accumulation of scale in the cooling device.

"Furthermore, the system is due to its short response time also suitable for discontinuous operation.

The requirement for increased controllability of the cooling intensity and its reproducibility is addressed in the invention Execution fulfilled in that it is connected by the central drain arranged above the cooling water level in the pipe with the secondary water supply is possible, the cooling pipe can also be operated with minimal water pressures, for example less than 1 atm, when the cooling tubes are completely full.

The built-in actuators 6 have an extensive influence the amount of water flowing through the cooling pipe possible, whereby an optimum of the desired cooling effect can be achieved according to the operating conditions.

The invention is intended to be in greater detail on the basis of exemplary embodiments explained:

1 shows an apparatus for carrying out the

method according to the invention.

Using the method of the invention there are several Variants with different setting conditions possible.

1) With the invention it is on the one hand possible to produce an unalloyed steel with a carbon content of 0.12 - C, 20 %,

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the dimension around 12 mm, with a smaller discharge of the partial water quantities from a final rolling temperature of 96O ⁰ C in a cooling time of 0.5 sec to a temperature of 620 C with a water consumption of 0 m / h. On the other hand the same steel grade of the same size can with a greater diversion of the partial amount of water of 96O ⁰ C in 0.5 sec at 55O ⁰ C at the same water consumption of 5 ° nr / h are cooled.

2) In another example, the control range due to the water chambers should also be shown. Unalloyed steel with 0.12-0.20% C is cooled from 103O ⁰ C with little partial water branching in 1 sec to 70O ⁰ C with an amount of Wasseip of 65 nr / h, whereas with large partial water branching and the same conditions it is cooled ^{to 63O 0 C} will. Furthermore, the embodiment according to the invention, with stable, uniform operation and the same controllability at low pressures, ie low water consumption, allows unalloyed steel with 0.12-0.2% C of dimensions around 12 mm to cool from 96O ⁰ C in 0.5 seconds 63O ⁰ C to, wherein the water consumption is 25 nr / h.

3) When using the cooling system for the high-temperature thermomechanical treatment of rolled steel with dimensions of around 16 mm, at coil rolling temperatures of 85O - 900 ⁰ C with a cooling water quantity of approx. 100 m / h in a cooling time of 1.5 - 2, 5 seconds a material temperature of = 10O ⁰ C can be achieved.

For Walzwtahl the dimension of approximately 12 mm is also at a final rolling temperature of 95O ° C and a water consumption of 50 nr / well, cooling to 61O ⁰ C h sec possible in 0.5.

4) On the other hand, the same material can measure around 12mm by changing the amount of secondary water with a constant final

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roll temperature of 95O ° C and equal in Tfesserverbrauch C, 5 sec also be cooled to 55O ⁰ C.

5) If the cooling tube according to the invention is round for the dimensions 28 - 32 mm when cooling from the rolling heat, on the other hand, with the aim of saving after the following T normalization treatment are used, so are with a cooling water consumption of 60 nr / h cooling speeds of 500 ° C / sec accessible.

The structure and function of the device will be explained in more detail below with reference to FIG. 1:

The pressurized water is fed to the nozzle heads 1 and passes through the cooling tubes 2 in the storage space.

After leaving the cooling water, the symmetrically constructed Cooling pipes 2 through the central drain 3, a certain subset is fed to the upstream water chambers 4 ·.

In these chambers, depending on the operating pressure, the cooling tubes 2 and those branched off from the cooling water return flow build up Partial water volume on a defined pre-pressure, the size of which is limited by the pressure present in the storage space. Through the geometric relationships of the water chamber 4- this acts at the same time as a water scraper, as the water outlet is parallel to the direction of movement of the rolling stock is largely prevented, for which purpose one or more partition walls 5 are used in the chamber will.

To control the partial water quantities branched off from the cooling water return flow Control valves 6 are used in the secondary lines.

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Claims (1)

2U0415 Patent Claims 1. A method for the controlled cooling of rolling stock, in particular bar material, wherein the warm rolling stock is one or more Passes through cooling sections in which the cooling water is fed in on the inlet and outlet side via nozzle heads and via a centrally arranged, the oppositely directed cooling water flows accumulating storage space is discharged, thereby characterized in that a cooling water pressure of greater than 0 atü, preferably 0.5 to 5 atü, in the cooling section is set, and that the cooling water return flow is returned above the level of the cooling section, wherein secondary cooling water flows from the cooling water return flow adjustable cooling water pressure, with which the rolling stock before entering or behind the exit from the cooling section is applied. 2. The method according to claim 1, characterized in that for the high-temperature thermomechanical treatment of rolling stock with a dimension of 10 to 16 mm 0 this material with a final rolling temperature of 850 to 900 ⁰ C with a cooling water amount of about 100 nr / h in a cooling time from 1.5 b:
will. 1.5 to 2.5 seconds to a temperature of = 10O ⁰ C cooled Process according to Claim 1, characterized in that rolled stock with a dimension of 12 mm round and a final rolling temperature of 95O ⁰ C with a water consumption of approx. 50 Br / h is cooled ^{to 61O 0 C in a cooling time of 0.5 sec.} Method according to claim 1, characterized in that rolling stock with a dimension of 12 mm round and a final roll emp er at ur of 95O ⁰ C by changing the secondary water amount with a water consumption of approx. 50 nr / h in a cooling time of 0.5 sec to approx. 55O ⁰ C is cooled. 5098A3 / 0550 -9- 5. The method according to claim 1, characterized in that for Achievement of a structure similar to normalization in rolling stock with a dimension of 28 - 32 mm around this material with a cooling water consumption of approx. 60 m- / h and a cooling speed of 500 ° / sec, it is cooled, 6. Device for the controlled cooling of rolling stock, in particular Rod material, the warm rolling stock passes through one or more cooling sections into which the cooling water enters and fed in on the outlet side via nozzle heads and via a centrally arranged, the oppositely directed cooling water flows accumulating storage space is discharged, thereby characterized in that the nozzle heads each have a water chamber is connected upstream with an overflow channel, which is connected to the cooling water return line via a secondary line and a control valve connected. 7. Apparatus according to claim 6, characterized in that the cooling water return flow line is designed as a riser pipe and is connected to the storage space. 8. Apparatus according to claim 6, characterized in that the secondary lines upstream of the drain control valve to the cooling water return line are connected. 9. Apparatus according to claim 6, 7 and 8, characterized geksinzeich.net, that the discharge control valve and the control valves are connected to a common actuator. 10. Apparatus according to claim 6 to 9i, characterized in that that the water chambers have one or more vertical partition walls that are offset from one another and have axially aligned recesses for the passage of the rolling stock. 509843/0550 Blank page