JP3276513B2 - Joining equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining device for restoring a partially cut tubular part in a machine using a tubular part such as a thermal power plant or a chemical plant.

[0002]

2. Description of the Related Art Conventionally, in a tubular part of various plants, as a method of restoring a partially cut tubular part, a pipe having the same length as the cut part is formed, and both ends of the pipe and remaining parts are formed. The method of forming a groove on the end of the pipe and manually welding them is mainly used.

[0003] Furthermore, a method in which a brazing material is attached between two pipes to be joined and then the two pipes are fixed and heated to join them together, or a method in which a pressing force is applied from outside to a joint between the pipes during heating. Was used.

[0004]

The above-mentioned conventional method for joining tubular parts has the following disadvantages.

[0005] In a chemical plant or a thermal power plant, a large number of pipes are densely arranged, and when one of the pipes needs to be cut and restored, the welding device described above requires a welding device. It may not be able to fit, so in such a case, cut all weldable areas,
It was necessary to cut off the surrounding pipes and sequentially weld them from the inner pipe, which involved a useless welding operation.

Further, when a large number of pipes are to be restored by a welding method, the pipes are so dense that it is often necessary to perform manual welding by an operator. While it is expected that the number of skilled welding workers will decrease in the future, there is a possibility that stable welding quality will not be obtained in the future.

Further, in the brazing method in which both pipes are fixed, in recovering a part from which a part of the pipe has been cut, the length of the pipe to be recovered is shorter than the length of the cut part. For this reason, one end to be joined can be easily joined, but when joining the other end, a gap is generated in the joint, and a work such as applying a pressing force to adjust the gap has occurred. Was.

Further, in this method, since the pressing force at the time of joining cannot be adjusted accurately, one part of the unjoined portion remains at the press-joined portion when the pressing force is insufficient, and FIG.
As shown in (b), there was a problem that the joint was compressed and deformed.

On the other hand, the method of applying a constant pressing force when joining using an external pressing device can adjust the pressing force, but as described above, one end is required in the case of restoring a part of the pipe. When joining the other end remaining after joining, a large stress is required to fill the generated gap, and there is a possibility that existing normal parts may be damaged.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides (1) a high-frequency heating device for joining tubes and a positioning device for holding the tubes so as not to restrain the thermal expansion of the tubes. , A joining device provided with a heating device for maintaining the temperature rise of the tubes and adjusting the temperature, and a restraining jig for holding two tubes to be joined so as to restrain the thermal expansion of the tubes.
Also, (2) a joining apparatus in which a strain gauge for measuring the thermal stress of the tube and a control device for controlling the heating temperature based on the signal are provided to the above-described configuration.

That is, the present invention provides, as the invention of (1), a high-frequency heating apparatus having a heating coil for heating a brazing material inserted between joining ends of two pipes to be joined; In order to adjust the difference between the two pipes at the time of joining, the movement of the pipe is restricted in the direction perpendicular to the axial direction of the pipe, and the thermal expansion in the axial direction of the pipe at the time of joining is movable without restraining A positioning device that supports an end, and a predetermined region on the remaining pipe side other than the joining end is heated to a temperature equal to or lower than the creep temperature of the same pipe material,
A heating device for holding, and a restraining jig for holding the peripheral surfaces of the two tubes and restraining thermal expansion in the axial direction of the two tubes, which are located outside the heating device and the joining end, respectively. And a joining device.

Further, as a second aspect of the present invention, there is provided a high-frequency heating apparatus having a heating coil for heating a brazing material inserted between the joining ends of two pipes to be joined; In order to adjust the misalignment of the pipe, the movement of the pipe is restricted in the direction perpendicular to the axial direction of the pipe, and the joint end is movably supported without restricting the thermal expansion in the axial direction of the pipe during joining. A positioning device, a heating device for raising and maintaining a predetermined area on the remaining pipe side other than the joining end to a temperature equal to or lower than the creep temperature of the same pipe material, and a heating device for positioning the heating device and the joining end outside the same. Then, each holding the peripheral surface of the two pipes, a restraining jig for restraining thermal expansion in the axial direction of the pipes, and measuring the thermal stress applied to the bonding end portion at the time of bonding A strain gauge attached to the pipe and a bonding pressure set in advance based on the measured value Also provides bonding apparatus characterized by comprising and a control device for controlling the heating temperature by the heating device so as to obtain.

[0013]

According to the present invention, the brazing material is first inserted between the joining ends of the pipes to be joined, and the pipe is held by the positioning device and the restraining jig. set. Power is supplied to the high-frequency heating device to heat the joint, and, for example, in the case of carbon steel, 0.1 mm is applied so that the pressurizing stress due to thermal expansion applied to the joint becomes appropriate.
The temperature is adjusted by heating with a heating device so as to be in the range of 5 to 0.8 gf / mm ² , and the joint is heated at a predetermined pressure for a certain period of time to join the joining ends. Since this heating device heats at a temperature equal to or lower than the creep temperature of the tube, it is possible to control the high temperature heated by the high frequency heating device. In addition, the positioning device restrains the pipe in the direction perpendicular to the axial direction of the pipe, but it can move freely in the axial direction of the pipe so as not to restrain the thermal expansion of the pipe at the time of joining. The two tubes to be joined are further positioned outside the heating device to restrain the thermal expansion of the tubes in order to eliminate the restriction of the thermal expansion and to apply an arbitrary pressing force. By providing such a restraining jig, the occurrence of excessive stress at the joint end can be prevented, and accurate and distortion-free joining can be achieved.

Further, in the invention of (2), in addition to the effect of the above-mentioned invention of (1), the thermal stress of the tube is measured by a strain gauge and inputted to a control device. Since the heating device is controlled so as to have a previously set bonding pressure, an appropriate bonding pressure is automatically set, and more accurate pipe bonding is performed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a front view of a joining apparatus according to an embodiment of the present invention, FIG. 2 is a view taken along the line XX, FIG. 3 is a detailed view of a positioning apparatus, (a) is a cross-sectional view, and (b) is That YY
It is an arrow view.

In these figures, reference numeral 1 denotes a clamp for holding two pipes 6 to be joined. As shown in FIG. 2, the clamp 1 is composed of, for example, two divided support parts 1a and 1b having a grip part 1c. 6 is fixed at upper and lower two places 6a and 6b. Due to this fixation, the tube 6 is restricted from moving in the longitudinal direction and cannot move, and the joint 13 of the tube 6 is also securely fixed. 2 clamps a position near the joint 13 in order to position the joint of the tube 6, and the clamp contacts the tube 6 via a plurality of bearings 2a as shown in FIG. This is a positioning device capable of permitting displacement, and this positioning device is held by a clamp 1 (not shown). Reference numeral 3 denotes a heating heater located inside the holding clamp for heating the general portion of the tube to a predetermined temperature and adjusting the temperature. Reference numeral 4 denotes a high-frequency heater for heating the joining portion 13 into which the brazing foil is inserted for joining. The heating coil is connected to an external high-frequency power supply 11 (not shown) and a matching transformer. Reference numeral 5 denotes a strain gauge attached to the vicinity of the joint of the tube 6 for measuring a pressing force, and reference numeral 8 denotes a thermocouple of the joint 13.

FIG. 4 is a block diagram of a control system of the joining device. A control device 10 is a control device installed at a place remote from a joining portion of the tube 6, and includes a strain gauge 5 attached to the tube 6, The signal from the junction thermocouple 8 is taken in, the stress and the temperature of the junction of the tube 6 and its vicinity are determined from the signal, the temperature is determined to be within or outside the set temperature, and the relationship between the predetermined stress and temperature is determined. The high-frequency power supply 11 is controlled to control heating by the high-frequency coil 4 and the DC power supply 12 to control heating adjustment of the heater 3.

Using such a joining apparatus, the joining test was performed using the pipe 6 as a seamless heat transfer tube JISSTBA24 for a heat exchanger. The test procedure is shown below.

(1) The tube to be joined is fixed using the clamp so that the gap at the joint is about 3 mm.

(2) Insert Fe-3% B amorphous braze 7 between joints 13 of pipes 6 to be joined, and length 500
By heating the heater 3 mm to about 400 ° C., the two tubes are brought into close contact with each other.

(3) The high frequency power supply 11 of the high frequency heating coil 4 attached to the joint 13
And the temperature of the heater 3 is adjusted so that the pressure applied to the joint 13 at this time becomes an appropriate stress. These are controlled by the controller 10 by the junction thermocouple 8.
, The high-frequency power supply 11 is controlled so that the temperature becomes 1200 ° C., the junction of the tubes is heated by the high-frequency coil 4, and the direct-current power supply 12 of the heater 3 is controlled so that the heating temperature is appropriate. The adjustment is performed so as to be a stress.

The above-mentioned appropriate stress is a stress required at the time of joining, and is 0.5 to 0.8 kgf / mm ² in the case of carbon steel.
This stress is generated by the thermal expansion of the joint by the high-frequency heating coil 4 and the thermal stress of the general part by the heater 3 at the time of joining. The thermal stress by the high-frequency heating coil 4 is such that the joining temperature is fixed at 1200 ° C. Thus, it is not possible to adjust the stress at the joint. Therefore, by adjusting the temperature of the heater 3, the joining stress can be adjusted to an appropriate value (0.5 to 0.8 kgf / mm in the case of carbon steel).
² ) Adjust so that

As described above, the high-frequency heating coil 4 has an appropriate temperature at the time of joining (not lower than the melting temperature of the inserted amorphous sheet and not higher than the temperature at which remarkable growth of crystal grains occurs).
(1 ° C. to 1300 ° C.). Since it is difficult to adjust the pressing force only by this, the temperature of the heater 3 is controlled so that the above-described appropriate stress acts on the bonding portion 13 at the time of bonding.

(4) 900 after holding at 1200 ° C. for 10 seconds
The temperature is lowered to 0 ° C., and at this time, the power of the heater 3 is turned off and air-cooled. All such heating controls are performed by the control device 10 described above, but it goes without saying that the heating may be adjusted manually without using the control device.

FIG. 5 shows a conventional joint 9 obtained by fixing and heating a joint 9 manufactured by such a joining apparatus as shown in FIG. This is shown in comparison with a schematic diagram (b) of the appearance of 9 '. In the joint 9 'according to the conventional method, the joint 13 is bulged due to an excessive stress due to being fixed in close contact. However, in the method of the present invention, no bulge is recognized as shown in FIG. It became clear that a joint was obtained.

[0026]

As described above, according to the present invention, according to the present invention, a high-frequency heating device for joining a tube, a positioning device for holding a tube so as not to restrain thermal expansion of the tube, and a temperature rise of the tube And a restraining jig for holding two pipes to be bonded so as to restrain the thermal expansion of the pipes. And a control device for controlling the heating temperature based on this signal, the joining device has the following effects.

(1) Unlike the manual welding method, the joint properties do not differ depending on the skill of the worker, and the pressure, which is the most important parameter at the time of brazing with respect to the conventional brazing method, is applied to the pipe. Since it can be easily controlled by a simple operation of heating, a joint having stable performance can be easily manufactured.

(2) In recent years, many large machines such as thermal power plants have been constructed in large numbers during the period of rapid economic growth, and the aging of these machines has become a problem. However, according to the present invention, these works can be performed easily and with high reliability without requiring a skilled worker.

[Brief description of the drawings]

FIG. 1 is a front view of a bonding apparatus according to an embodiment of the present invention.

FIG. 2 is a view taken along the line XX in FIG. 1;

FIG. 3 is a detailed view of the positioning device in FIG. 1, (a)
Is a side view, and (b) is a view taken along the line YY.

FIG. 4 is a block diagram of a control system of the joining apparatus according to one embodiment of the present invention.

FIG. 5 is a view of a joint, (a) according to the present invention,
(B) is a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Clamp 2 Positioning device 3 Heater 4 High frequency heating coil 5 Strain gauge 6 Tube 7 Amorphous brazing 8 Joint thermocouple 9 Joint 10 Control device 11 High frequency power supply 12 DC power supply

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-7-32194 (JP, A) JP-A-1-165183 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 1/002 B23K 1/18 B23K 3/00 B23K 11/02 F16B 7/00 F16B 11/00

Claims (2)

(57) [Claims] 1. A high-frequency heating device having a heating coil for heating a brazing material inserted between joining ends of two tubes to be joined, and adjusting a difference between the two tubes when joining the joining ends. In order to restrain the movement of the pipe in a direction perpendicular to the axial direction of the pipe, a positioning device that supports the joint end movably without restricting the thermal expansion in the axial direction of the pipe at the time of joining; A heating device for raising and holding a predetermined area on the remaining pipe side other than the end to a temperature equal to or lower than the creep temperature of the pipe material; and a heating device located outside the heating device and the joining end, and A joining jig for holding a peripheral surface of the tube and restraining thermal expansion in the axial direction of the tube. 2. A high-frequency heating device having a heating coil for heating a brazing material inserted between joining ends of two pipes to be joined, and adjusting a difference between the two pipes when joining the joining ends. In order to restrain the movement of the pipe in a direction perpendicular to the axial direction of the pipe, a positioning device that supports the joint end movably without restricting the thermal expansion in the axial direction of the pipe at the time of joining; A heating device for raising and holding a predetermined area on the remaining pipe side other than the end to a temperature equal to or lower than the creep temperature of the pipe material; and a heating device located outside the heating device and the joining end, and A restraining jig for holding the peripheral surface of the pipe and restraining thermal expansion in the axial direction of the pipe, and attached to the pipe to measure thermal stress applied to the joint end during joining. A strain gauge and the above-described pressure are applied so that a predetermined bonding pressure can be obtained based on the measured value. A joining device, comprising: a control device for controlling a heating temperature by the heating device.