JPS58168404A - Rolling method of pipe in second piercer - Google Patents

Abstract

PURPOSE:To prevent the generation of flaw on the inside surface of a metallic pipe owing to the friction and seizure between a mandrel and the inside surface of the metallic pipe by cooling the inside surface of the metallic pipe then coating a graphite lubricant thereon in the stage of piercing the metallic pipe with the 2nd piercer in producing the metallic pipe by a Mannesmann double piercing system. CONSTITUTION:The thick walled hollow blank pipe P which is formed with the 1st piercer in a pipe making process by Mannesmann plug mill by a double piercing system is finished to a metallic pipe by expanding and rolling with a plug and drum-type rolls in the 2nd piercer. Cooling water is first injected from the nozzle 4a of an injector 4 for high pressure cooling water to the inside surface of the pipe P to cool the pipe near the inlet of the pierced pipe P, thereby descaling the inside surface of the blank pipe. Fine powder of a graphite solid lubricant is then injected from the nozzle 5a of a supply device 5 to the inside surface of the pipe P. The friction and seizure between the plug of the 2nd piercer and the inside surface of the blank pipe are prevented and the metallic pipe having an excellent inside surface shape is produced stably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seamless tube rolling method using a roll perforation method, particularly to a method for rolling a pipe using a second perforation machine of the so-called Mannesmann double perforation method.

In the so-called Mannesmann plug mill pipe manufacturing method, which uses a double perforation method, a thick-walled hollow raw pipe (
After obtaining the perforated material (hereinafter referred to as perforated material), the perforated material is subsequently expanded and rolled using a pair of barrel-shaped rolls and a plug in a second perforation machine (Elongator). During this rolling, the plug and the material to be rolled are There has been a problem in that avatar-like flaws are likely to occur on the inner surface of the rolled material due to friction and seizure with the inner surface, and the rolling speed is also reduced. Therefore, the object of the present invention is to When rolling perforated materials using the second perforator of the Mannesmann Plug Mill pipe manufacturing process, by eliminating friction and seizure between the plug and the inner surface of the rolled material, the inner surface properties of the rolled material and the rolling speed can be improved. It is an object of the present invention to provide a method of rolling a tube in a second i-hole machine that can achieve the above-mentioned results.

That is, in the present invention, near the entrance of the second drilling machine,
At least the rear end of the perforated material is injected with a high-pressure cooling liquid to descale the rear end, and at the same time the rear end is cooled to a temperature that does not cause carburization, and then a graphite-based lubricant is applied to the perforated material. The present invention is characterized in that the perforated material is fed into the hole to lubricate the inner surface of the perforated material during rolling by the second perforation machine.Next, the present invention will be explained based on the drawings.

The attached drawings show an example of equipment suitable for carrying out the present invention, and FIGS. 1 to 3 show a first drilling machine (not shown).
and a second drilling machine (not shown).
FIG. 4 shows a device for spraying high-pressure coolant T onto the inner surface of the perforated material and injecting lubricant into the perforated material.

The drilling material rotating device shown in FIGS. 1 to 3 is provided on a table 1 near the entrance of a second drilling machine, and has n1 pairs of rotating rows 22.
, 2', and the rollers 2, 2' have an upper operating position (indicated by a solid line in FIGS. 1 and 2) and a lower retracted position (indicated by a broken line in FIGS. 1 and 2). It consists of a cylinder mechanism 3 that moves up and down between the cylinders.

Now, when the hollow perforating material P is discharged from the first perforating machine and transported onto the table 1, the supply of the perforating material P is detected by a known appropriate position detection means, and the cylinder mechanism 3 is actuated and moved to the operating position above t10-22,2''i.As a result, the perforated material P is lifted from the table 1 by the rollers 2, 2' and rotated by the rotation of the rollers 2, 2'. This rotating drilling material P
On the other hand, each nozzle portion 4a of the high-pressure cooling flow injection device 4 and the lubricant supply device 5 shown in FIG.

5at is inserted, first, high-pressure cooling liquid is injected from the nozzle 4a to the rear end Pa of the perforated material P to descale and cool the inner surface of the rear end Pa of the perforated material, and then graphite-based lubricant is applied to the perforated material from the nozzle 5a. Inject onto the inner surface of the rear end Pa of the material. As a result, the inner surface of the perforated material P is uniformly descaled and cooled in the circumferential direction, and the lubricant is uniformly applied to the inner surface of the perforated material P. It may be performed over the entire length, or it may be performed only on the rear end Pa of the perforated material P. In the case where the cutting is performed only on the rear end part pa, it is usually sufficient to target a range of about 1 to 2 m from the rear end of the perforated material P, although this varies depending on the pipe length of the perforated material P. There is usually a temperature difference of about 20C between the front end and the rear end of the perforated material P, and the friction and seizure between the plug and the rolled material during rolling by the second perforation machine mainly occur within the above range. Due to the fact that the occurrence of inner surface defects of the rolled material and the places where the rolling speed decreases are concentrated at the rear end, it is possible to improve the rolling material by descaling, cooling, and applying lubricant at least to this rear end. This is because the inner surface properties of the perforated material can be considerably improved and the rolling speed can be increased, and a substantially uniform temperature distribution can be obtained in the length direction of the perforated material by cooling the rear end of the perforated material.

In order to effectively descale at least the rear end portion of the inner surface of the perforated material P, the injection pressure of the coolant should be approximately 7 to 135
It is preferable that the injection amount be approximately 1 yl/mvr, and it is desirable that the injection be performed for about 2 to 5 seconds at a flow rate of about 1 yl/mvr.

On the other hand, according to the present invention, the graphite-based lubricant is applied after cooling the inner surface of the perforated material P.
It is necessary to cool the inner surface to a temperature that does not cause carburization. The critical temperature for carburization is, for example, about 1150° C. for low carbon steels. Therefore, in this case, it is necessary to cool the inner surface of the perforated material to a temperature of 1150 degrees Celsius or less by spraying the coolant, and for this reason, it is necessary to spray the coolant under the spray conditions specified above for about 2 to 5 seconds. 0 The amount of graphite-based lubricant to be added is approximately 209 g to the rear end of the perforated material in the above range, and when applying lubricant to the entire length of the perforated material, it is approximately 50 g per per perforated material. , the effects of the present invention can be achieved.

As a device for performing high-pressure coolant injection and lubricant injection according to the present invention, one having the configuration shown in FIG. 4 is preferably used. The supply device 4 is placed on a cart 6 and can be moved to a predetermined position behind the table 1 as required. The nozzle portion 4a of the high-pressure coolant injection device 4 and the nozzle portion 5a of the lubricant supply device 5 are also connected to the trolley 6.
It is connected to the arm of a cylinder 7 placed on the table 1, and when the perforated material P is conveyed from the first perforation machine to a predetermined position on the table 1, it is pushed forward by the air cylinder 7. It is inserted into the hollow part from the rear end of the perforated material P. The cooling liquid is supplied at a predetermined pressure via a pump 8, and the lubricant is supplied in fixed quantities by a metering device provided in a hopper 9, and the lubricant is supplied by air. A pump 8 for supplying coolant and a hopper 9 for supplying lubricant are provided at separate locations outside the truck 6, and are configured to be connected to the nozzles 4a and 5b on the truck 6 by means of flexible tubes or the like. Next, the effects of the present invention will be explained using examples.

In the examples, the apparatus shown in FIGS. 1 to 4 was used.

Example 1 Inner surface temperature near the inlet of the second drilling machine: 118
Flow to high carbon steel perforated material at 0~1190℃ 11 yen-1 pressure 8
Spray cooling water for 2 seconds on the inner surface to a temperature of 1100 to 1120.
When comparing the rolling speed in the second perforator when 50I graphite is charged after cooling and descaling to °C with the rolling speed when the method of the present invention is not applied, Table 1 also shows the dimensions of the perforated material before and after rolling. It is as follows. Note that the rolling speed is expressed as perforation efficiency (M x 100).

Table 1 Example 2 Inner surface temperature near the inlet of the second drilling machine 119
Flow rate 1yl/miR for low carbon steel perforation material at 0~1210℃
, spray cooling water at a pressure of 81 for 3 to 5 seconds to cool the inner surface to 113
After cooling and descaling to 0 to 1150° C., 50 g of graphite was added and the rolled material was rolled using a perforation machine. The inner surface properties of the rolled material are as shown in Table 2, which also shows the dimensions of the perforation material before and after rolling.

As is clear from the results shown in Tables 1 and 2, the present invention not only makes it possible to increase the rolling speed in the second punching machine, but also greatly improves the inner surface properties of the raw pipe after rolling. can do.

[Brief explanation of drawings]

Fig. 1 is a schematic front view of the drilling material rotation device used in the present invention, Fig. 2 is a side view thereof, Fig. 3 is a rear view thereof, and Fig. 4 is a high-pressure coolant injection device and lubrication device used in the present invention. This is a schematic diagram of the agent supply device.・Pump 9...Hopper

Claims (1)

[Claims] (1) In the vicinity of the inlet of the second perforated material, at least the rear end of the perforated material is descaled by injecting high-pressure cooling liquid to at least the rear end of the perforated material, and at the same time the rear end is brought to a temperature at which carburization does not occur. 1. A method for rolling a pipe using a second punching machine, characterized in that the tube is cooled to a temperature of 100 mL, and then a graphite-based lubricant is poured into the punching material to lubricate the inner surface of the punching material during rolling by the second punching machine.