JPS5923819A - Cooling method of pipe material - Google Patents

Abstract

PURPOSE:To cool homogeneously and efficiently a pipe material without bending the same by holding the pipe material in a heted state with press rolls on driving rolls, and injecting cooling fluid from a nozzle group disposed in parallel with the pipe material while rotating the material at a prescribed speed or above. CONSTITUTION:A pipe material 11 which is kept heated to a high temp. is carried onto driving rolls 16 of a cooler 15 and is held while it is held pressed onto the rolls 16 by press rolls 17. The material 11 which is held as mentioned above is rotated by the rolls 16 at >=60 revolutions/min. rotating speed and is cooled from the outside by the cooling fluid injected from the cooling nozzles 19 of cooling headers 18. The uniform cooling in the axial and circumfeential directions of the material 11 is thus made possible. The required number of the headers 18 to be installed around the pipe 11 is decreased if the material 11 is revolved at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of cooling a tube material, and more particularly to a method of cooling a tube material that is suitable for controlling and cooling a tube material in a high temperature state at a cooling rate intermediate between natural cooling and water quenching.

Recently, due to the increase in the tensile strength of various types of pipe materials, including oil well steel pipes used in oil and gas production, the proportion of pipe materials that require heat treatment such as quenching and tempering or normalizing after pipe production has increased. are doing.

Heat treatment for upper pipes has been in practical use for a long time, and in recent years many proposals have been made regarding quenching and tempering methods and equipment, and efforts have been made to improve the quenching and tempering technology.

However, when it comes to normalizing in a tube, it only relies on natural cooling in the atmosphere, which remains the same as before. The reason why pipe material normalization is not used frequently is that it is difficult to uniformly control and cool the pipe material, which results in uneven material quality and the occurrence of bends due to uneven cooling. be.

In particular, as shown in FIG.
As shown in FIG. 2, in the method of cooling the tube 2 from the outside using a cooling device 5 that injects cooling fluid from a plurality of cooling nozzles 4 surrounding the circumferential concavity of the tube 2, the tube 2 is cooled in the axial direction. Due to the transport and the positional relationship of the cooling nozzle 4, the cooling fluid enters the inside of the tube material 2 from either of the ends of the tube material 2, and the cooling rate at the end of the tube material 2 is compared to the cooling rate at the intermediate portion. This results in non-uniformity of the material in the axial direction of the tube material 2 and bends in the ends thereof.

In addition, in the case of using the cooling device 5, the cooling fluid flowing along the surface of the tube material 20 collides with the conveyance roller 3, and behind the conveyance roller 3, cooling in the circumferential direction of the tube material 20 becomes extremely non-uniform. This causes non-uniformity of the material in the circumferential direction.

Therefore, in the cooling device 5, in order to eliminate the non-uniformity of the material in the circumferential direction of the tube material 2, a method is adopted in which the tube material 2 is conveyed in the axial direction while being rotated by a skew roller. As the conveyance speed decreases, the rotation speed also decreases, and it is difficult to obtain a rotation speed of 20 revolutions per minute or more except for some small diameter steel pipes, and it is impossible to achieve sufficient uniform cooling in the circumferential direction. It is also possible to eliminate the flow of cooling fluid on the surface of the pipe material by making the injection direction of the cooling nozzle parallel to the plane perpendicular to the pipe axis, but in that case, the required equipment would be large-scale. Therefore, it is difficult to put it into practical use.

Note that the cooling distribution device 5 is mainly used for quenching the pipe material 2, and when the cooling device 5 described in “2” is applied to controlled cooling, the temperature at room temperature or the transformation end temperature, etc. is determined within a limited cooling zone. Since it is necessary to cool the upper material 2 to a predetermined temperature at a relatively slow cooling rate, there is also the problem that the transport speed of the tube material 2 to be heat treated is significantly reduced, which greatly impedes productivity.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for cooling a pipe material that enables efficient and controlled cooling of a pipe material uniformly and without bending.

In order to achieve the above object, the present invention provides a cooling method in which a heated pipe material is cooled by jetting a cooling fluid, in which the pipe material is held on a drive roll by a presser roll and is driven by the drive roll. The tube is rotated at a rotational speed j1 of 60 rotations or more and cooled by cooling fluid injected from a group of cooling nozzles arranged parallel to the tube.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a front view showing an example of an apparatus used for carrying out the present invention. The pipe material 11 that has been reheated to a high temperature in the heating device or heated to a high temperature by hot rolling is transported to a predetermined position by the transport rollers 12, and then transferred to the transport table 14 by the operation of the feeder 13.
After that, it is transported to the cooling device 15 side.

The cooling device 15 includes a -7;1 drive roll 16 that can support the tube material 11, and a presser roll 17 that can hold the tube material 11 in an upwardly extending position on the drive roll 16. That is,
The presser roll 17 moves up and down with respect to the pipe material 11 on the drive roll 16, and applies a pressure of 100 to 1000 kl to the pipe material 11.
The pipe material 11 is moved to the driving roll 16 under the following load.
It can be held on top. Further, the drive roll 16 holds the pipe material 11 held by the presser roll 17.
It is possible to rotate at a rotation speed of 60 rotations or more.

Furthermore, cooling headers 18 are arranged in parallel in the longitudinal direction of the tube 11 at a plurality of positions (three positions) around the tube 11 on the drive roll 16 . Each cooling header 18 is equipped with a number of cooling nozzles 19 that can inject cooling fluid toward the outer surface of the tube 11 . In addition, in Figure 3, 20
21 shows a kicking device that allows the tube material 11 after cooling to be kicked out from the drive roll 16, and 21 indicates a chain conveyor that allows the tube material 11 kicked out by the kicking device 20 to be sent out to the outside of the cooling device @15. It shows.

Next, the operation of the above HIE embodiment will be explained. The pipe material 11 in a high temperature heated state is heated by the driving roll 1 of the cooling device 15.
After being carried onto the drive roll 16, the drive roll 16 is held under pressure by the presser roll 11. Furthermore,
The tube material 11 is rotated at a rotational speed of 60 rotations or more by the driving of the drive roll 16 under the holding state described in -1-, and its outer surface is rotated by the cooling fluid injected from the cooling nozzle 19 of the cooling header 18 cooled from

In addition, since pipe materials generally bend during cooling due to the occurrence of scale on their surface and variations in wall thickness at various positions in the circumferential direction, the presser roll 11 as in the above embodiment is not used. When rotation is provided by the drive roll 16, it is impossible to provide continuous high-speed rotation to the evening moon 11. That is, as in the above embodiment, the tube 1 on the drive roll 16-H
1, presser rolls 17 are arranged at multiple positions in the longitudinal direction.
By applying rotation to the tube material 11 by the drive roll 16 while the tube material 11 is held by the presser roll 17, the tube material 11 can be rotated at high speed regardless of whether or not the tube material 110 bends during cooling. Here, the pressing force applied by the presser roll 17 to the tube material 11 is 1. OOkg
If the pressing force is less than 1.000 kg, bending of the striped pipe material 110 cannot be prevented, and if the pressing force exceeds 1.000 kg, deformation or flaws will occur in the pipe material.
00, 9 or more 1000kl? It is recommended to set it within the following range.

According to the embodiment described above, the tube material 11 is rotated at high speed without moving in the axial direction, and the eugetsu 11 is cooled from the outer surface by cooling fluid injected from a large number of cooling nozzles 19 arranged parallel to the tube material 11. Therefore, it becomes possible to uniformly cool the tube material 11 in the axial direction and the circumferential direction. 1. By rotating the Yoigetsu 11 at high speed, it is possible to reduce the number of cooling headers 18 required to be installed around the pipe material 11. Note that the number of installed cooling headers 18 and the injection pressure from the cooling nozzles 19 are determined depending on the cooling speed IW to be applied to the pipe material 11, dimensions such as the outer diameter and wall thickness of the eugetsu 11, and the quality of pipe control. By appropriately selecting the cooling rate according to the temporal change in the cooling rate, that is, the cooling pattern, etc., it becomes possible to controllably cool the Yoizuki 11 at a wide range of cooling rates.

Moreover, the pipe material 1 to which the cooling method according to the present invention is applied 1:1
1 can be applied not only to control after hot rolling is completed, but also to Yozuki in the middle of hot rolling. It's Kade.
The cooling device 15 used in the implementation of the present invention includes a pipe material 1
1, it is possible to reduce the number of cooling headers 18 required to be installed. Therefore, it is possible to supply cooling fluid to provide a large cooling speed to the pipe material 11, such as in quenching, within the device. It becomes possible to arrange the header in parallel with the cooling header 18.

That is, by filling the inside of the cooling device 15 in the above embodiment with cooling fluid in advance and installing an inner surface cooling header that can inject the cooling fluid onto the inner surface of the pipe material 11 as necessary, the cooling device 15 can be used to cool the pipe material 11. It can also be used for hardening.

Hereinafter, specific implementation results of the present invention will be explained. The first to seventh examples in this specific implementation result are C0,
15%, Si 0.20%, Mn 1.30%, an outer diameter of 139.7n+n+, and a wall thickness of 10.54mm, which were reheated to 920°C and then cooled. Here, in the first to fourth examples, a pressing force of 300 Kf was applied to the pipe material using the apparatus shown in FIG.
This relates to the method of the present invention in which the pipe material is rotated at high speed, and the fifth
Examples and 6th example relate to a comparative method in which the tube material was rotated at low speed using the apparatus shown in Fig. 3, and Example 7 relates to a conventional method using the apparatus shown in Fig. This is related to.

Table 1 shows the respective cooling conditions in Examples 1 to 7 described in 105-, the Vickers hardness at the inner surface 1 silk position measured at 8 points in the circumferential direction of the cooled pipe material, and the amount of bending due to cooling. It becomes a street.

As shown in Table 1, according to the method of the present invention, a material with a small standard deviation of hardness, that is, uniform in the circumferential direction, can be obtained, and the bending is less than 1" per 1-71, which is extremely good. It becomes a state. On the other hand, even if the device shown in Fig. 3 is used, if the comparative method is used in which the rotational speed applied to the pipe material is less than 60 rotations, the material will be non-uniform in the circumferential direction and bending will occur more frequently. . In addition, in the case of the conventional method, a large number of nozzles are arranged in the circumferential direction of the pipe H, and although it is thought that cooling of the pipe material surface to which the cooling fluid from the nozzles is directly injected is uniform, the conveyance roller It is recognized that the non-uniformity of the material due to the interference with the cooling fluid and the low rotational speed is very large, and the occurrence of bending is also large.

In addition, in the 8th to 12th examples in the concrete implementation results, the Yogetsu hot-rolled to have an outer diameter of 60.3 F1 ms and a wall thickness of 4.83 mm was not allowed to cool naturally on its rolled surface.
Each was cooled. Here, in the 8th to 10th examples, 200 k
The 11th example relates to the method of the present invention in which a pressing force of g is applied and the tube material is rotated at -ζ 1 speed, and the 11th example relates to a comparative method in which the tube material is rotated at a low speed of 7j using the apparatus shown in Figure 3. The twelfth example relates to a conventional method using l'j''r 1 and the apparatus shown in FIG.

Each cooling condition in the above-mentioned 8th to 12th examples, the inner surface I measured at 8 points in the circumferential direction of the cooled pipe material
Table 2 shows the pincushion at the 111 position and the steepness of the curve due to cooling.

As shown in Table 2, even when the tube material is cooled immediately after hot rolling, the present invention cools the tube material while giving it a rotational speed of 60 rotations or more, as in the case of cooling after reheating. Only by using this method, it is possible to obtain uniform material quality and good straightness in the circumferential position of the pipe material. In carrying out the method of the present invention, if scale on the surface of the tube is removed, it becomes possible to cool the tube more uniformly.

As described above, the method for cooling a pipe material according to the present invention includes holding the pipe material on the drive roll with the presser roll, and
The tube is rotated at a rotation speed of 60 rotations or more by driving the drive roll, and cooled by cooling fluid jetted from a group of cooling nozzles arranged parallel to the tube, so that the tube is uniform and does not bend. This makes it possible to efficiently control cooling without any problems.

[Brief explanation of drawings]

FIG. 1 is a side view showing a device used in a conventional method for cooling pipe materials, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a method for cooling pipe materials according to the present invention. 1 is a cross-sectional view showing an example of an apparatus used for carrying out. DESCRIPTION OF SYMBOLS 11... Tube material, 15... Cooling device, 16... Drive roller, 17... Embossing roll, 18... Cooling header, 19... Cooling nozzle. Agent Patent Attorney Osamu Shiokawa

Claims (1)

[Claims] (1) In a tube cooling method in which a heated tube is cooled by jetting a cooling fluid, the tube is held on a drive roll by a presser roll, and the drive roll is driven to rotate the tube at 60 revolutions per minute or more. Characteristic cooling method for pipe materials.