COOLING DEVICE FOR SEAMLESS STEEL PIPES

Abstract

Cooling device (1) for cooling a seamless, rolled pipe (R) made of a metal, preferably steel, which has a nozzle assembly (10) comprising one or more nozzles (14), which are configured to apply a cooling medium (K), preferably water or a water mixture, to the outer circumferential surface of the pipe (R) while the pipe (R) is transported along a conveying direction (F) through a cooling section of the cooling device (1), wherein the nozzle assembly (10) has an access (Z), via which the pipe (R) can be removed from the cooling section in the radial direction of the pipe (R), preferably upward.

Claims

1.-16. (canceled)

17. A cooling device (1) for cooling a seamless, rolled pipe (R) made of a metal, comprising: a nozzle assembly (10) comprising one or more nozzles (14), which are configured to apply a cooling medium (K) to an outer circumferential surface of the pipe (R) while the pipe (R) is transported along a conveying direction (F) through a cooling section of the cooling device (1), wherein the nozzle assembly (10) has an access (Z), via which the pipe (R) can be removed from the cooling section in a radial direction of the pipe (R).

18. The cooling device (1) according to claim 17, wherein the cooling medium (K) is water or a water mixture and wherein the radial direction is upward.

19. The cooling device (1) according to claim 17, wherein the nozzle assembly (10) comprises one or more nozzle arms (11), each comprising at least one distribution pipe (12) and one or more nozzle lances (13) attached to and extending from the at least one distribution pipe (12), and wherein each nozzle lance comprises one or more nozzles (14).

20. The cooling device (1) according to claim 19, wherein the at least one distribution pipe (12) comprises a plurality of distribution pipes (12), wherein the cooling device (1) further comprises a fluid system, which is configured to supply the distribution pipes (12) with the cooling medium (K), and wherein the distribution pipes (12) are combined to form a fluid unit (20) that is served by a common pump (21) and/or switched by a common valve system.

21. The cooling device (1) according to claim 19, characterized in that the at least one distribution pipe (12) is configured to convey the cooling medium (K) in a cross-sectional plane of the pipe (R) and/or along the conveying direction (F).

22. The cooling device (1) according to claim 17, wherein the cooling section is 8 to 16 m long.

23. The cooling device (1) according to claim 17, wherein a position and/or orientation and/or volume flow rate of one or more nozzles (14) of the nozzle assembly (10) is adjustable.

24. The cooling device (1) according to claim 17, wherein the nozzles (14) of the nozzle assembly (10) are configured to form a plurality of spray levels (S), which are adjustable along the conveying direction (F).

25. The cooling device (1) according to claim 17, wherein the cooling device (1) is configured to cool the pipe (R) to a final temperature of 450° C. to 600° C.

26. The cooling device (1) according to claim 17, wherein the cooling device (1) is configured to perform a section-by-section or quasi-continuous control of pressure and/or flow rates of the cooling medium (K).

27. The cooling device (1) according to claim 17, wherein the cooling section is subdivided into a plurality of sections, wherein, in a first section, the nozzle assembly (10) is configured for high-pressure spraying with pressures of more than 10 bar and in a subsequent section in the conveying direction (F) for lower pressures.

28. The cooling device (1) according to claim 17, wherein the cooling device (1) is configured for discontinuous operation in such a way that one or more nozzles (14) is/are switched on upon entry of the pipe (R) into the cooling section and is switched off upon exit of the pipe (R) from the cooling section, and wherein one or more sensors, which are configured for detecting pipe ends, are arranged inside or downstream of the cooling section.

29. The cooling device (1) according to claim 17, further comprising an enclosure which completely or partially surrounds the nozzle assembly (10) and/or one or more compressed air wipers.

30. The cooling device (1) according to claim 17, wherein the conveying direction (F) of the pipe (R) along the cooling section is inclined relative to the horizontal.

31. The cooling device (1) according to claim 17, the cooling device (1) being arranged immediately downstream of a rolling mill for rolling the pipe (R), such that the pipe (R) enters the cooling section while it is still engaged in the rolling mill at a downstream end.

32. A device, comprising: a rolling mill; and the cooling device according to claim 17, wherein the cooling device is located downstream of the rolling mill in the conveying direction (F) and configured for cooling the pipe (R) rolled by the rolling mill.

33. The device according to claim 32, wherein the rolling mill comprises one or more cooling elements configured to lower a temperature of the pipe (R) in the rolling mill below the Ar3 transformation point.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a schematic cross-sectional view of the nozzle assembly of a continuous cooling section with an attached fluid unit in accordance with one embodiment;

[0035] FIG. 2 shows the nozzle assembly of FIG. 1 in a top view;

[0036] FIG. 3 is a schematic cross-sectional view of the nozzle assembly of a continuous cooling section in accordance with a further embodiment;

[0037] FIG. 4 shows a top view of the nozzle assembly in accordance with FIG. 3 with an attached fluid unit.

DETAILED DESCRIPTION

[0038] Preferred exemplary embodiments are described below with reference to the figures. Thereby, identical, similar or similarly acting elements are provided with identical reference signs in the various figures, and a repeated description of such elements is sometimes omitted in order to avoid redundancies.

[0039] FIG. 1 is a schematic cross-sectional view of the nozzle assembly 10 of a continuous cooling section with an attached fluid unit 20 in accordance with one embodiment. FIG. 2 shows the nozzle assembly 10 in a top view.

[0040] The nozzle assembly 10 is part of a cooling device 1, which is arranged as a continuous cooling section preferably directly downstream of a rolling mill for rolling seamless pipes R. In this context, the term “directly” means that the pipe R enters the continuous cooling section while it is still engaged in the rear end of the rolling mill, as seen in the conveying direction F (see FIG. 2).

[0041] The pipe R is made of a metal, preferably steel, comprising in particular high-quality alloys suitable for use in oil and gas production or for structural pipes.

[0042] The rolling mill set forth above, not shown in the figures, is preferably a stretch-reducing rolling mill or a sizing mill, which has a plurality of roll stands arranged one behind the other in the conveying direction F of the pipe R. The parent pipes coming from an upstream unit are inserted into the rolling mill in the hot-rolled condition. The operating temperatures are in the range between 900° C. and 1,000° C., for example. Upon leaving the rolling mill, the pipe R preferably has a temperature of over 820° C. to 840° C.

[0043] The nozzle assembly 10 has one or more nozzle arms 11, each having at least one distribution pipe 12 and one or more nozzle lances 13 attached thereto and extending therefrom, each having one or more nozzles 14. The distribution pipes 12 are supplied with a cooling medium K, preferably water or a water mixture, via a fluid system, which then flows to the nozzles 14 via the nozzle lances 13 and is discharged or sprayed, as the case may be, by them onto the pipe R.

[0044] The nozzle arms 11 with their distribution pipes 12 and nozzle lances 13 may be arranged in levels referred to herein as “spray levels” S. In the present exemplary embodiment, each spray level S has, by way of example, two nozzle arms 11, each with a distribution pipe 12 and five nozzle lances 13 connected thereto. However, there is no restriction in this respect. Rather, the number and arrangement of the nozzle arms 11, nozzle lances 13 along with nozzles 14 can be freely selected as long as the uniform cooling of the pipe R is ensured and the nozzle assembly 10 does not comprise any closed-ring-type structures, as explained further below.

[0045] In FIG. 2, only two spray levels S are shown. However, the number of spray levels S arranged along the conveying path of the pipe S is usually larger, in order to provide a sufficient cooling effect. The cooling section, that is, that section of the conveying path in which the cooling medium K is applied to the pipe R, can be comparatively short, for example 8 to 16 m, depending on the number, position and orientation of the nozzles 14, the throughput of the cooling medium K, etc.

[0046] The nozzle assembly 10 can be configured such that the spray levels S or a part thereof are adjustable along the conveying direction F. For this purpose, the nozzle arms 11 or a part of them may be displaceably mounted. Alternatively or additionally, the nozzle lances 13 or a part thereof can be arranged to swivel, for example by the corresponding nozzle arms 11 being mounted to rotate about their own axes. Further, it is not essential that the nozzle assembly 10 form a plurality of well-defined spray levels. The nozzle lances 13 with their nozzles 14 can, for example, be positioned and/or aligned in such a way that the pipe R, viewed in the conveying direction F, is essentially uniformly applied with the cooling medium K.

[0047] A plurality of distribution pipes 12 may be combined into one fluid unit 20 each, which is served by a common pump 21 and/or switched by a common valve system.

[0048] In accordance with the exemplary embodiment of FIGS. 1 and 2, the distribution pipes 12 convey the cooling medium K in the cross-sectional plane of the pipe R. Alternatively, the cooling medium K can also be conveyed along the longitudinal axis of the pipe (=conveying direction F), as shown in the exemplary embodiment of FIGS. 3 and 4. Of course, the distribution pipes 12 may be arranged in other ways, as long as the access Z outlined below is provided.

[0049] It has already been pointed out that the nozzle assembly 10 does not comprise closed-ring-type structures. Rather, the nozzle arms 11 are designed to be open at least on one side, so that the pipe R may be removed from the cooling section in the radial direction, preferably upward, in the event of a malfunction (accident). In other words, the nozzle assembly 10 leaves an unobstructed gap or access Z along the conveying direction F through which the pipe R can be removed, if necessary. The working space in the region of the access Z is not obstructed by lines, pipes or the like. The dimension of the access Z is larger than the diameter of the pipe R, in order to ensure the unobstructed removal of the pipe R from the cooling section.

[0050] Thus, a cooling section is created which, on the one hand, is short enough to be able to process still undivided pipe conduits of, for example, up to 100 m in length, and from which, on the other hand, the pipes R can be easily removed, for example in the event of a malfunction, in particular without having to cut them first at the spray levels S.

[0051] In order to ensure uniform cooling along the circumference of the pipe despite the absence of concentric distribution rings, the nozzles 14 can be configured, arranged and aligned in such a way that the quantity of cooling medium K sprayed on is essentially constant along the circumference of the pipe. In other words, the flow rate of cooling medium K per nozzle 14 and the direction of radiation can be adjusted to achieve, or at least approximate, symmetrical and concentric cooling. In the case of rectilinear distribution pipes 12, as shown in FIG. 1, the nozzle lances 13 can be longer at the edge sections than in the center of the corresponding distribution pipe 12 for this purpose, by which the nozzles 14 are located at least approximately on an imaginary partial ring.

[0052] The cooling device 1 presented herein is suitable for cooling the pipes R to final temperatures of approximately 450° C. to 600° C., by which a particularly fine-grained microstructure can be obtained. Following cooling by the cooling device 1, the pipe R can be further cooled to room temperature by air convection.

[0053] In conjunction with an upstream rolling train, the parent pipe is preferably first cooled to temperatures below the Ar1 transformation point and then reheated to rolling temperature. The pipe R is then rolled in the rolling mill and transferred or transported to the cooling device 1 for subsequent rapid cooling.

[0054] In accordance with an advantageous embodiment example, the cooling section is divided into several sections, wherein, in a first section, the nozzle assembly 10 is configured for high-pressure spraying, for example with pressures of more than 10 bar, and in a subsequent section in the conveying direction F for lower pressures. In the high-pressure range, for example, heat transfer coefficients of more than 10,000 W/(m.sup.2K) are achievable.

[0055] Alternatively or additionally, a section-by-section or quasi-continuous control of pressure and/or flow rates of the cooling medium K, viewed in the conveying direction F, can be implemented as a function of the product and/or based on measured values, empirical values and/or a process model.

[0056] The cooling device 1 can be configured for discontinuous operation in that nozzle arms 11 can be switched on, for example, in accordance with the passage of the front end of the pipe and switched off with the passage of the rear end of the pipe, thereby preventing cooling medium K from entering the pipe R. For this purpose, one or more sensors configured to detect the pipe ends can be located inside or downstream of the cooling section.

[0057] Preferably, the cooling section is located completely or section-by-section in an enclosure, in order to avoid the contamination of the environment with cooling medium K, in particular to reduce spray water and water vapor contamination of the environment. For a similar purpose, compressed air wipers can be used to prevent the cooling medium K from entering particularly vulnerable equipment, such as radiometric wall thickness or other measuring points upstream and/or downstream of the cooling section.

[0058] The conveying direction F of the pipe R along the cooling section can be inclined (rising or falling), which can shorten the installation space during the transition from the rolling mill to any cooling bed. Additionally or alternatively, the cooling section can be integrated into the transition region to the cooling bed. Since the spray chamber is not closed due to the access Z, the pipe R can be lifted out of the cooling section and transferred to the cooling bed.

[0059] The cooling device 1 presented herein is also suitable for combination with auxiliary cooling elements in the rolling mill, in order to enhance the cooling effect. In accordance with one exemplary embodiment, a lowering of the feed or rolling temperature takes place in the rolling mill, such that a lower final rolling temperature than is normally the case is applied. In the rolling mill, for example, the pipe R can be sub-cooled to a temperature of approximately 30° C. below the Ar3 transformation point.

[0060] To the extent applicable, any of the individual features set forth in the exemplary embodiments may be combined and/or interchanged without departing from the scope of the invention.

LIST OF REFERENCE SIGNS

[0061] 1 Cooling device [0062] 10 Nozzle assembly [0063] 11 Nozzle arm [0064] 12 Distribution pipe [0065] 13 Nozzle lance [0066] 14 Nozzle [0067] 20 Fluid unit [0068] 21 Pump [0069] R Pipe [0070] F Conveying direction [0071] K Cooling medium [0072] S Spray level [0073] Z Access