JPH04371523A - Heat treatment apparatus for welding part in electric resistance seam welded tube - Google Patents

Abstract

PURPOSE:To make it possible to always measure the max. temp. in a weld part even even if the weld line of an electric resistance seam welded tube is twisted, and to prevent the excessive heat input by controlling the input quantity of heat into a post-annealer based on the measured max. temp. CONSTITUTION:In a heat treatment apparatus for the weld part in the electric resistance seam welded tube 1, plural number of temp. detectors 9, 10, 11 set at the prescribed measuring point interval in the direction crossing at the right angle to a weld line 2 at outlet side of post-annealer, a selector 19 outputting the max. temp. by selecting it from the measured results of temp. inputted from the temp. detectors 9, 10, 11 and a control part 7 for controlling the heat input quantity for the post-annealers 4, 5, 6 by comparing the max. temp. inputted from the selector 19 with the set temp., are added. By this method, in the case twisting angle of the weld line for the electric resistance seam welded tube is large, measurement of the accurate heat treatment temp. can be executed, and the heat input control of the post-annealers can be accurately executed, and improvement of characteristic at the weld part is attained with the suitable heat treatment and also, electric power consumption can be saved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a post-annealing heat treatment apparatus for improving the performance of welded parts when manufacturing high-grade electric resistance welded steel pipes such as line pipes.

0002

2. Description of the Related Art Mills that manufacture high-grade electric resistance welded steel pipes such as line pipes are equipped with a local heat treatment device called a post annealer after welding to improve the performance of the hardened weld. In this post-annealing process, a specially shaped inductor is used to locally reheat only the welded area in a width of 20 to 30mm by induction heating. Various performances such as low-temperature toughness and corrosion resistance are greatly improved.

[0003] In the above-described post-annealing, it is important to accurately heat the welded portion to a predetermined temperature. However, in a production line for electric resistance welded steel pipes, the weld line of the steel pipe exhibits complicated movements as the steel pipe advances due to various reasons such as the shape of the strip and the positional relationship of forming rolls. for example,
There are approximately 50 weld lines at both ends of a 10 m long ERW steel pipe.
It shifts by mm. Therefore, even if the heat treatment device is set at a fixed position, the weld line does not always fall within the heating width range of about 20 to 30 mm, and this position often shifts and complete heat treatment cannot be performed. In addition, in post-annealing, the degree of penetration of heating into the entire tube thickness is originally important, but in conventional technology, only the maximum temperature reached is controlled, so the degree of penetration is unknown. It is heated to a high maximum temperature.

[0004] As a method for dealing with the deviation of the weld line of the above-mentioned electric resistance welded steel pipes, a temperature sensor is used to scan across the weld zone to determine the temperature distribution in the direction perpendicular to the weld line, and the temperature sensor is used as a standard. A method of integrally moving a temperature detector and a heating inductor connected to the rear part of the temperature detector so that the point is located at the position showing the maximum temperature of the temperature distribution (Japanese Patent Application Laid-open No. 1983-1999)
161589), a method of detecting the center of the heating section by measuring the temperature distribution of the heating section at a position in front of the post-annealer, and adjusting the position of the post-annealer so that this center coincides with the center of the post-annealer (Japanese Patent Application Laid-open No. 161589). Showa 6
1-231123) etc. have been proposed.

[0005] In addition, as a method for preventing variations in the degree of penetration of heating into the entire tube thickness, that is, the temperature on the inner surface of the tube, the heating width and maximum temperature are detected at a position subsequent to the post-annealer, and the detected results are A method of adjusting the amount of heat input based on the heat input amount (Japanese Unexamined Patent Publication No. 61-231122) has been proposed.

[0006]

[Problem to be solved by the invention] The above-mentioned Japanese Patent Application Laid-Open No. 55-16
The method disclosed in Japanese Patent Application Laid-open No. 1589 and Japanese Patent Application Laid-open No. 61-231123 detects the center of the weld line based on the temperature distribution in the circumferential direction of the electric resistance welded steel pipe, and heats the weld line by aligning this center with the center of the post annealer. . However, in all of these methods, the temperature detector and the post-annealer are simply moved integrally to the center of the weld line detected by the circumferential temperature distribution, and control of the heat treatment temperature is not considered. In addition, the method disclosed in Japanese Patent Application Laid-Open No. 61-231122 is
The temperature distribution in the circumferential direction is measured on the exit side of the post-annealer to detect the heating width and maximum temperature at a predetermined temperature, and the required amount of heat input is calculated from the detection results. In other words, the current amount of heat input and the temperature of the inner surface of the tube are estimated from the maximum temperature and heating width,
This is compared with a reference value to calculate the amount of heat input, and based on this calculation result, the voltage applied to the post annealer is controlled to control the amount of heat input to the steel pipe. However, the temperature distribution on the exit side of the post-annealer actually has a problem in that the measured temperature value is low due to problems such as twisting of the welded part, and the control thereof causes excessive heat input to the post-annealer.

An object of the present invention is to be able to always measure the maximum temperature of the welded part even if the weld line of the ERW steel pipe is twisted, and to prevent excessive heat input by controlling the amount of heat input to the post annealer based on the measured maximum temperature. An object of the present invention is to provide a heat treatment apparatus that can prevent heat input.

[0009]

[Means for Solving the Problems] The present inventors have conducted various studies in order to achieve the above object. As a result, by arranging multiple temperature detectors at predetermined measurement point intervals in the weld width direction on the exit side of the post-annealer, and selecting the highest temperature value among the temperature values measured by the multiple temperature detectors. , Even if the weld line is twisted, the welded part showing the highest temperature can always be detected, and excessive heat input can be prevented by controlling the amount of heat input to the post annealer by using the selected maximum value as the heat treatment temperature of the welded part. We came to this conclusion and arrived at this invention.

That is, the present invention provides an electric resistance welding machine that is provided with a welding position detector on the entrance side of a heat treatment apparatus, and has means for controlling the center of the post annealer to be located at the center of the welded part based on the detection result of the welding position detector. In heat treatment equipment for steel pipe welds, multiple temperature detectors are installed at predetermined measurement point intervals in the direction perpendicular to the weld line on the exit side of the post-annealer, and the maximum temperature is determined from the temperature measurement results input from the multiple temperature detectors. This is a heat treatment device for welded parts of ERW steel pipes, which is equipped with a selector that selects and outputs the temperature, and a control unit that compares the maximum temperature input from the selector with the set temperature and controls the amount of heat input to the post annealer. .

[0011]

[Operation] In the present invention, a heat treatment apparatus for a welded portion of ERW steel pipes includes a plurality of temperature detectors disposed at predetermined measurement point intervals in a direction perpendicular to the weld line on the exit side of the post annealer, and It is equipped with a selector that selects and outputs the maximum temperature from the temperature measurement results input from the heat sink, and a control unit that compares the maximum temperature input from the selector with the set temperature and controls the amount of heat input to the post annealer. , the temperature in the width direction of the welded part of the ERW steel pipe is measured by multiple temperature detectors, the highest temperature is selected by the selector, and the control unit controls the heat treatment temperature by controlling the amount of heat input to the post annealer based on that value. will be held. Therefore, even if the welded part of the ERW steel pipe is twisted and the highest temperature part is shifted in the width direction, it can be measured, and the amount of heat input to the post annealer, which has tended to be controlled excessively in the past, can be appropriately controlled. , the electric resistance welded steel pipe can be heat treated at a predetermined heat treatment temperature.

[0012] In the present invention, the plurality of temperature detectors disposed on the exit side of the post-annealer in a direction perpendicular to the weld line are as follows:
Non-contact radiation thermometers and optical thermometers are used, and it is preferable to install two or more thermometers, but from the viewpoint of installation space, welded part twist width, cost, measurement accuracy, etc., three is appropriate. Dew. Further, the installation interval of the temperature detectors is preferably approximately 10 mm between measurement points, taking into consideration the bead width. Furthermore, it is advisable to configure the plurality of temperature detectors so that they can follow the welding position in accordance with the detection result of the welding part center position by the welding position detector.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the apparatus of the present invention will be explained below with reference to FIGS. 1 and 2 showing an example of its implementation. FIG. 1 shows how the temperature detector is installed, with (a) being a front view and (b) being a side view. FIG. 2 is a control block diagram of the device of this invention. In FIGS. 1 and 2, 1 is an electric resistance welded steel pipe, and 2 is a welding line of the electric resistance welded steel pipe 1. 3 is No. 1 Welding position detector arranged on the entrance side of post annealer 4, 5 is No. 2 post annealer, 6 is No. It is a 3 post annealer. The welding position detected by the welding position detector 3 is output to the control section 7, and No. The centers of the first to third post annealers 4, 5, and 6 are controlled to follow the center of the welding position. 8 is No.
a temperature detector disposed on the outlet side of the 2-post annealer 5, 9;
10 and 11 are No. Three temperature detectors are arranged on the exit side of the 3-post annealer 6, and the temperature detectors 9, 10, 11 are arranged at a measurement point interval of 1 in the direction orthogonal to the weld line 2 of the ERW steel pipe 1.
0mm, weld line 2 along slide rails 12, 12
It is fixed to a sliding plate 13 that is movable in a direction perpendicular to the . When a screw 15 supported by fixed bearings 14 and 14 is rotated by a handle 16, a nut 16 screwed onto the screw 15 is connected to the sliding plate 13 via a connecting member 17.
When the handle 18 is turned and the screw 15 is rotated, the sliding plate 13 is configured to reciprocate along the slide rails 12, 12.

The temperature measurement results of the welded portion detected by the temperature detectors 9, 10, and 11 are outputted to the selector 19, and the highest temperature among them is selected by the selector 19. The selected maximum temperature is output to the control section 7. Control unit 7
compares the maximum temperature input from the selector 19 and the set heat treatment temperature input in advance from the setting device 20,
No. The amount of heat input to the first to third post annealers 4, 5, and 6 is calculated, the applied voltage is controlled, and the welded portion of the electric resistance welded steel pipe 1 is heated to a predetermined heat treatment temperature. Note that 21 is a printer and 22 is a marker.

With the above configuration, the weld line 2 of the electric resistance welded steel pipe 1 is twisted and the post annealer 4, 5
, 6 deviates in the circumferential direction, it is measured by one of the plurality of temperature detectors 9, 10, 11, and the selector 19 selects the highest temperature. The control unit 7 compares the maximum temperature selected by the selector 19 with the set heat treatment temperature inputted in advance from the setting device 20, and selects No. Since the amount of heat input to the first to third post annealers 4, 5, and 6 is calculated to control the applied voltage, the welded portion of the electric resistance welded steel pipe 1 is heated to a predetermined heat treatment temperature. Therefore, the post-annealer heat input control, which was conventionally controlled by excessive heat input,
The amount of heat input is controlled with high precision, allowing for power savings.

[0016]

[Effect of the invention] As described above, according to this invention,
Even when the twist angle of the ERW steel pipe weld line is large,
It becomes possible to accurately detect the heat treatment temperature, perform highly accurate heat input control in the post-annealer, enable appropriate heat treatment, improve the performance of the welded part, and save power.

[Brief explanation of drawings]

FIG. 1 shows the installation status of a temperature sensor according to the present invention, in which FIG. 1A is a front view and FIG. 1B is a side view.

FIG. 2 is a control block diagram of the inventive device.

[Explanation of symbols]

1 ERW steel pipe 2 Welding line 3 Welding position detector 4 No. 1 post anila 5 No. 2 post annealer 6 No. 3 post annealer 7 Control section 8, 9, 10, 11 Temperature detector 12 Slide rail 13 Sliding plate 14 Bearing 15 Screw 16 Nut 17 Engagement member 18 Handle 19 Selector 20 Setting device 21 Printer 22 Marker

Claims (1)

[Claims] 1. An electric resistance welded steel pipe welding section, comprising: a welding position detector provided on the entry side of a heat treatment device; and means for controlling the center of the post annealer to be located at the center of the welded section based on the detection result of the welding position detector. In this heat treatment equipment, multiple temperature detectors are installed at predetermined measurement point intervals in the direction perpendicular to the weld line on the exit side of the post-annealer, and the highest temperature is selected from the temperature measurement results input from the multiple temperature detectors. A heat treatment device for welded parts of ERW steel pipes, which is equipped with a selector that outputs the temperature and a control unit that compares the maximum temperature input from the selector with the set temperature and controls the amount of heat input to the post annealer.