JPS61276732A - Method and device for upsetting pipe - Google Patents

Abstract

PURPOSE:To liberate the shape control of the inner face taper part by gradually reducing forward the steady part side from thicker part the heating temp. distribution of the pipe end intermediate part and by performing the thickness forming via a die and punch under the state thereof. CONSTITUTION:In the heating stage of the steel pipe 10 to be upsetted two zones of a soaking zone and temp. controlling zone are set. The temp. measuring instrument 21 composed of noncontact type thermometers 21A-21E is provided on the temp. control zone and a cooling device 23 is arranged on the upper part position of the steel pipe 10 as well. A controller 22 operates the cooling curve of the cooling device 23 changing the actual temp. distribution to the optimal temp. distribution by comparing the actual temp. distribution measured by the temp. measuring instrument 21 with the optimal temp. distribution set on the temp. control zone in advance. Adjusting valves 24A-24E are then controlled based on said cooling curve. In this method, the slope and length of the inner face taper part are freely controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for upsetting a pipe.

[Prior Art] As a method for connecting long steel pipes such as oil country tubular goods, a method is used in which the steel pipes are successively connected by interposing a joint in a threaded portion formed at the end of the steel pipe. In steel pipes to which this connection method is applied, in order to ensure the strength of the threaded portion formed at the pipe end, the pipe end portion is formed into a thick wall by upsetting.

Kitaki Upset processing involves heating the tube end, sandwiching the outer surface of the heated tube end with a die, and inserting the core metal part of the flanged punch whose diameter has been reduced to a predetermined size into the inner surface of the tube end. The punch is used to compress the tube end to form a thick wall.

Incidentally, the tube end subjected to the above-mentioned upset processing is formed with an inner surface tapered portion sandwiched between the inner surface of the tube end thick portion and the inner surface of the tube steady portion. This internal tapered part is important for preventing fatigue failure at the boundary between the thick-walled part of the pipe end and the steady part of the pipe, and when the steel pipe is used under harsh conditions such as in a drill pipe, It is desirable to set the inner taper portion to be gentle and long.

[Problems to be solved by the invention] However, in the conventional upset processing method,
The heating temperature distribution in the longitudinal direction at the tube end portion changes with a steep gradient between the heated region and the non-heated region, and the heating temperature distribution in the longitudinal direction at the intermediate portion of the tube end, which forms the internal tapered portion, is determined. Therefore, the internal taper obtained by upsetting becomes steep and short, and it is impossible to freely set the slope and length.

Therefore, in the conventional upset processing method, when attempting to obtain a predetermined shape in the inner surface tapered portion, it is necessary to machine the inner surface of the tube end after thick-walled molding or to treat it with a grinder.

Incidentally, as shown in Japanese Unexamined Patent Publication No. 59-215221, a technique has been proposed that allows the shape of the thick walled portion at the end of the tube to be controlled; has not been proposed at all.

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to control the shape of the inner surface tapered portion sandwiched between the inner surface of the tube end thick wall portion and the inner surface of the tube steady portion.

[Means for Solving the Problems] A first aspect of the present invention is to heat a tube end portion, clamp the outer surface of the heated tube end portion with a die, and apply a flanged punch to the outer surface of the tube end portion in a predetermined position. In the pipe upset processing method, in which a core metal part whose diameter has been reduced to the specified size is inserted, and the pipe end is compressed by the punch to form a thick wall, the pipe is sandwiched between the inner surface of the thick wall part of the pipe end and the inner surface of the steady part of the pipe. While the heating temperature distribution in the middle part of the pipe end, where the inner surface taper part is formed, is gradually reduced from the notch in the thick part of the pipe end towards the steady part of the pipe, the thickness is The meat is molded.

The second aspect of the present invention also includes a heating device that heats the tube end portion, a die that clamps the outer surface of the heated tube end portion, and a die that is reduced in diameter to a predetermined size that can be inserted into the inner surface of the tube end portion. In a pipe upset processing device, the punch is equipped with a flanged punch that compresses the pipe end to form a thick wall. A temperature measuring device that measures the heating temperature distribution in the longitudinal direction of the intermediate portion of the tube end that forms the inner surface tapered portion, and a temperature measuring device that is capable of cooling the heated intermediate portion of the tube end, and that cools the heated intermediate portion of the tube end. Based on the measurement results of a cooling device that is variable along the longitudinal direction of the intermediate portion and a temperature measuring device, the operation of the cooling device is controlled, and the heating temperature distribution of the intermediate portion of the tube end is adjusted to the side of the thick walled portion of the tube end. and a controller that gradually reduces the amount of water from the tube toward the stationary portion of the tube.

[Function] According to the tube upset processing method and apparatus according to the present invention, the heating temperature distribution in the tube end intermediate portion where the inner surface taper portion is formed is controlled in the longitudinal direction of the tube end portion, This makes it possible to freely control the slope and length of the inner tapered portion obtained by the 7-set process.

[Example] Fig. 1 is a control system diagram showing the heating temperature distribution control state at the middle part of the tube end, Fig. 2 is a front view showing the overall configuration of the upset processing device, and Fig. 3 is a main part showing the upsetting processing state. FIG.

The steel pipe 10 to be upset processed is heated by a heating device (burner type or high frequency induction heating furnace) 1, as shown in FIG.
1, the tube end portion is heated.

The heated steel pipe 10 passes through a skid rail 12 and reaches an upset processing position, where it is subjected to an upset processing using a die 13 and a flanged punch 14. Dice 13
sandwich the outer surface of the heated pipe end portion of the steel pipe 10, and the punch 14 includes a mandrel portion 15 whose diameter is reduced to a predetermined size so as to be inserted into the inner surface of the pipe end portion. Dice 1
3 and the punch 14, as shown in FIG.
The tube end portion shown by the dotted chain line is compressed to form a thick wall.

Thereby, the steel pipe 10 is formed with a pipe end thick walled part 16,
An inner tapered portion 18 is formed in a portion sandwiched between the inner surface of the tube end thick wall portion 16 and the inner surface of the tube steady portion 17. Note that 19 is an outer surface tapered portion sandwiched between the outer surface of the tube end thick-walled portion 19'1 and the outer surface of the tube steady portion 17.

However, in the steel pipe 10, the inner tapered portion 1
The shape of 8 can be controlled as follows.

First, the steel pipe 10 is heated in a heating process by the heating device 11 in the circular areas of the soaking area and the temperature control area as shown in FIG. Soaking area.

The length is set in advance from the end surface of the steel pipe 10 to a length predicted to correspond to the inner surface upset length (the inner length of the thick walled part 16 of the pipe end), and is shown by the solid line A-B in FIG. It is heated to a predetermined constant temperature. The temperature control area is set in advance to the length of the tube end intermediate portion 20 that is predicted to correspond to the inner taper length (the length of the inner taper portion 18) from the end point of the soaking area. Broken line B in Figure 1
It is heated to a temperature distribution as shown by C.

Next, the steel pipe 10 is heated to a temperature measuring device 21 shown in FIG.
As a result, the heating temperature distribution in the longitudinal direction of the tube end intermediate portion 20, that is, the temperature control region, is measured. Temperature measuring device 2
1 is composed of a plurality (5) of non-contact thermometers 21A to 21H arranged along the longitudinal direction of the tube end intermediate portion 20, and the measurement results of each thermometer 21A to 21H are sent to a controller 2.
2 can be transmitted.

On the other hand, above the steel pipe 10 located on the skid rail 12, a cooling device 23 is installed. The cooling device 23 includes the thermometers 21A to 21A along the longitudinal direction of the tube end intermediate portion 20.
It has a plurality of (5) cooling nozzles 23A to 23E arranged corresponding to the measurement site 21E. Each of the cooling nozzles 23A to 23E is connected to a cooling water supply pipe 25 via a water flow control valve 24A to 24E, each of which is controlled by the controller 22. That is, the cooling device 23 makes its cooling capacity variable along the longitudinal direction of the tube end intermediate portion 20 while adjusting the amount of water ejected from each of the cooling nozzles 23A to 23E.

Here, the controller 22 controls the temperature control of the tube end intermediate portion 20 before the upset processing, that is, the temperature control, in order to form the desired shape surface tapered portion 18 on the inner surface of the tube end intermediate portion 20 after the upset processing. The optimum temperature distribution to be set in the region is set in advance in one diagram to a state where it gradually decreases from the side of the thick walled part 16 of the pipe end to the side of the steady part 17 of the pipe, as shown by the solid line B-D in FIG. , is memorized as a function expression.

Therefore, the controller 22 compares the optimum temperature distribution defined in the temperature control area with the actual temperature distribution measured by the temperature measuring device 21, and is necessary to change the actual temperature distribution to the optimum temperature distribution. A cooling curve (shown by a dashed line in FIG. 1) of the cooling device 23 is calculated. Based on this calculation result, the controller 22 controls each water flow control valve 24A of the cooling device 23.
~24E is operated and controlled.

That is, according to the above embodiment, the heating temperature distribution of the tube end intermediate portion 20 where the inner surface tapered portion 18 is formed is controlled in the longitudinal direction of the tube end portion, and thereby, the inner surface tapered portion 18 is formed. It becomes possible to freely control the slope and length of the inner surface tapered portion 18.

FIG. 4 is a diagram showing the specific effect of the present invention, showing the extension ratio of the inner surface taper length with respect to the change in the amount of inner wall thickness increase. According to the present invention, compared to the conventional method, the inner surface It becomes possible to set the taper length dramatically and gradually.

In addition, in implementing the present invention, the cooling device 23 may not be automatically controlled by the controller 22, but the operation of the cooling device 23 may be controlled by manual operation.

[Effects of the Invention] As described above, according to the tube upsetting method and apparatus according to the present invention, the heating temperature distribution at the intermediate portion of the tube end where the inner surface taper portion is formed in the longitudinal direction of the tube end portion is improved. This makes it possible to freely control the slope and length of the inner tapered portion obtained by upsetting.

[Brief explanation of the drawing]

Fig. 1 is a control system diagram showing the heating temperature distribution control state at the middle part of the tube end, Fig. 2 is a front view showing the overall configuration of the upset processing device, Fig. 3 is a sectional view of the neck part showing the upsetting processing state, FIG. 4 is a diagram showing specific effects of the present invention. DESCRIPTION OF SYMBOLS 10... Steel pipe, 11... Heating device, 13... Die, 14... Punch with flange, 15... Core metal part, 16... Tube end thick wall part, 17... Pipe Steady part, 18.
・Inner tapered part, 20 ・Pipe end middle part, 21 ・・
- Temperature measuring device, 22...controller, 23...cooling device. Agent Patent Attorney Osamu Shiokawa 1st Part 2

Claims (2)

[Claims] (1) Heat the tube end portion, clamp the outer surface of the heated tube end portion with a die, insert the core metal part of the flanged punch whose diameter has been reduced to a predetermined size into the outer surface of the tube end portion, and In the pipe upsetting method in which the pipe end is compressed with a punch to form a thick wall, the middle part of the pipe end is sandwiched between the inner surface of the thick wall part of the pipe end and the inner face of the steady part of the pipe to form an inner tapered part. A method for upsetting a tube, characterized in that thick-wall forming is performed using the die and punch described above under a state in which the heating temperature distribution is gradually reduced from the side of the thick-walled portion of the tube end toward the side of the steady-state portion of the tube. (2) A heating device that heats the tube end, a die that clamps the outer surface of the heated tube end, and a metal core whose diameter is reduced to a predetermined size that can be inserted into the inner surface of the tube end. Prepare,
In a tube upset processing device having a flanged punch for compressing and forming a thick tube end, an inner tapered portion is formed between the inner surface of the thick wall portion of the tube end and the inner surface of the steady portion of the tube. A temperature measuring device that measures the heating temperature distribution in the longitudinal direction of the intermediate portion of a tube end, which is capable of cooling the heated intermediate portion of the tube end, and which is capable of controlling the cooling capacity along the longitudinal direction of the intermediate portion of the tube end. The operation of the cooling device is controlled based on the measurement results of the variable cooling device and the temperature measuring device, and the heating temperature distribution at the intermediate portion of the tube end is directed from the side of the thick walled portion of the tube end to the side of the steady portion of the tube. and a controller for gradually reducing the upsetting of a pipe.