JPS59187206A - Method for detecting welded position of seam welded pipe - Google Patents

Abstract

PURPOSE:To detect the welded part accurately and to make it possible to perform accurate heat treatment, by adding the powder of a fluorescent light emitting material into a marking paint, performing marking, emitting ultraviolet rays at the time of reading, and reading the marks. CONSTITUTION:As a marking paint, a colorless transparent paint, in which the powder of fluorescent light emitting material is added, is used. Said paint is jetted to a seam welded pipe 8 at the upstream side of a post annealer 4a at the foremost front stage by a marking device 17. A strip shaped straight line 18 is marked at the specified angle position from a welding line 7. Ultraviolet rays are emitted from ultraviolet ray devices 21a-21x and excited, and the marks are read by image sensor cameras 12a-12x. Inductors 5a-5x follow the welding line 7 through controllers 13a-13x. Therefore, the welding line 7 is accurately detected and heat treatment is performed. Under the normal light, the strip shaped marks appear only as the degree of water leakage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an induction heating device that continuously heat-treats the bath welding part after welding in the manufacturing process of electric resistance welded pipes. The present invention relates to a method for accurately detecting the position of a bath contact portion in the vicinity of the heating device.

As is well known, in the manufacture of electric resistance welded pipes, a metal strip finished to a predetermined width is continuously rolled while passing through forming rolls, and a high-frequency current is supplied to heat both sides of the abutting portion, which is then pressed together with a squeeze roll. This is done by passing through a shaping roll and correcting it to a predetermined size. In general, the mechanical properties of a welded part deteriorate compared to the base metal due to the influence of heat, so a boss annealer is installed to anneal the welded part after 5 welding. Be it. However, it is common for electric resistance welded pipes to run while twisting to the left or right, albeit gently. Therefore, even if the inductor of the boss annealer is initially placed correctly on the bath tangent, it will gradually become misaligned. The position of the welded part at each stage of the boss annealer must be constantly monitored, and the inductor position of the boss annealer must be corrected immediately if it changes from the reference position.

Conventionally, as a method for detecting the position of the welded part, ■ As shown in Fig. 1, an eddy current type contact part detector 6 is installed between the first-stage boss annealer 4a and the squeeze roll 2, and this detects the amount of torsion XQ of the bath contact part. The amount of torsion of the m contact part at the center of the squeeze roll is set to 0, and the amount of torsion of the τ electric contact part X1 to XM at each stage of the boss annealer is proportional to the distance 6□ to ex from the center of the squeeze roll. The position of the m-contact portion 7 of each stage 4a to 4x is determined. As the m-contact detector 6, a temperature Kuhn detector may be used in some cases.

■ As shown in Figure 2, each stage of boss annealer 4a to 4X
Temperature pattern detectors 10a to 10x on the inlet or outlet side of
is installed to detect the temperature peak portion of the electric resistance welded pipe 8, and this peak position is regarded as the bath contact portion 7.

When there are two or more boss annealers, one may not be provided with a temperature pattern detector, and one in several may be provided with a temperature pattern detector.

■ As shown in FIG. 3, a marker 14 is used to continuously mark with white paint at a predetermined angle in the circumferential direction from the m-contact part 7 of the ERW tube 8 upstream of the first-stage boss annealer 4a. Bost Annealer 4 with this mark 15
Image sensor camera 12a installed near 8~4x
The position of the welded portion 7 is indirectly determined by reading it with ~12x.

When there are two or more boss annealers, an image sensor camera may not be provided on a one-to-one basis, but one image sensor camera may be provided for every several boss annealers.

This is a conventional method for detecting the position of the m-joint, but these conventional methods have the following drawbacks: The current situation is that this is not the case.

■ The above conventional method ■ uses boss annealer stages 4a to 4x.
It is a mistake to estimate the position of the m-contact part in It's not uniform. In addition, the eddy current flaw detection type bath contact detection device 6 uses a weak high-frequency signal, which is subject to interference from the outputs of the inductors 5a to 5X of the boss door Annie 2, as well as due to size constraints. The device 6 cannot be installed between each stage of the boss annealer.

■ The above conventional method ■ uses the highest stage boss annealer 4.
Except for the temperature pattern detector installed on the inlet side of a, the heat position of each stage 42 to 4x of the boss annealer is regarded as a welding part, so that one electric contact part is not detected.

(2) With the conventional method (2), the position of the welded part can be accurately detected by using the boss annealer at each stage 42, but it is difficult to erase the mark 15, and unless this problem is solved, it will not be possible to make the weld part.

The present invention completely eliminates the drawbacks of the conventional method as described above, accurately detects the m-junction, uses this as a position reference, and allows the inductor of each stage of the boss annealer to follow the junction, allowing accurate heat treatment. It is something to do.

The present invention continuously marks a position at a predetermined angle in the circumferential direction from the welded part on the ERW pipe upstream of the boss annealer, and places this mark at a position corresponding to the m-joint part at each stage of the boss annealer 2. This is applied to detection as a marking material, and a quick-drying oil-based paint to which fluorescent material powder or bright reflective material powder is added is used as the marking paint.

Number on the surface of the ERW tube? The strip-shaped mark sprayed with a width of m passes through various types of cooling water, squeeze rolls, pinch rolls, etc., and is exposed to the image sensor camera under conditions where it is irradiated with a light source corresponding to the paint additive at the entrance or exit side of each stage of the boss annealer. Read by. By using the upper etch part position of the strip mark read in this way as a position control reference,
The inductors at each stage of the Boss Door Annie 2 should be able to accurately follow the electrically connected portions to accurately anneal the target area. Moreover, under a normal light source, the band-like mark looks only like a water mark and does not need to be erased, which is very convenient. Next, the present invention will be explained in detail.

FIG. 4 is a schematic plan view of the main parts of the electric resistance welded tube manufacturing process, in which 1 is a fin pass roll, and the copper strip is gradually rolled into a circular shape by a forming roll before this roll.

The circular steel strip coming out of the fin pass roll 1 is transferred to a high frequency bath welding device 1.
6, both side edges of the abutting portion are heated to a high temperature, and are crimped with a squeeze roll 2 to form an electric resistance welded tube 8. After the squeeze roll 2, a pipe inner and outer surface cutting device, a sizing roll, etc. are installed, but they are omitted in this figure. 4a - 5 is a post annealer, and 52 to 5x are inductors therein, which are installed far behind the bath welding machine 16 and are heated in a width of, for example, 35 mm, with the tangential line 7 of the electric rod tube 8 as the center. Perform annealing treatment. 7 is a marking device installed upstream of the boss annealer 4a according to the present invention, which sprays a colorless and transparent paint doped with fluorescent material powder.

A continuous band-shaped straight line 18 is marked, for example, at a position 900 in the circumferential direction from the bath tangent line 7. 22 is a pressurized air injection device for draining, 23 is a hot air injection device for forced drying the paint, and these marking device 17 and pressurized air injection device 2
2. The height and width of the hot air injection device 23 can be adjusted according to the outer diameter of the electric resistance welded tube.

The inductors 5a to 5x of the boss annealer have a positioning drive device and its control device, but these are omitted in this figure.

The marked electric resistance welded tube 8 passes through the squeeze roll 2 and the pinch roll 3a and reaches the boss annealer 4a.

The band-like mark 18 that is irradiated by the ultraviolet irradiators 21a to 21x installed at the entrance side of each stage of the boss annealer 43 to 4x and excite the rays 2 to emit fluorescence is the image sensor camera 12a-1.
2x and converted into the amount of change from the reference position by the controllers 13a to 13x. By making the inductors 5a to 5X follow the m tangent 18 using this as a position control reference, the contact portion can be annealed accurately.

The image sensor cameras 1221 to 12x require a filter that blocks ultraviolet rays and other light other than fluorescent light and has a high transmittance for fluorescent light. The detection location must be shielded from external light as necessary. The height and width of the ultraviolet irradiators 21a to 21x and the image sensor cameras 12a to 12X can be adjusted according to the outer diameter of the ERW tube. Decide by considering. The controllers 13a to 13X are capable of correcting changes in curvature due to changes in the outer diameter of the electric resistance welded tube.

Since band marks on ERW pipes remain even after various subsequent processes (excluding main tube heat treatment), water pressure testing machines, bath contact flaw detection equipment, and flatness testing machines are required to know the bath contact position in subsequent processes. Needless to say, it can be used for other purposes. Also, markings may be applied not only after the pipe is formed (but also on the back side of the hoop before forming, at a predetermined angular position from the bath contact area after forming).

[Brief explanation of the drawing]

FIGS. 1 to 3 are explanatory diagrams showing a conventional method for detecting the position of an m-contact part, and FIG. 4 is an explanatory diagram showing a method for detecting a bath contact part from one company according to the present invention. 1--fin pass roll, 2... squeeze roll, 3a
+ 31)...pinch roll, 4a"-, 4x...boss annealer, 53~5x...inductor, 7...bath tangent,
8... ERW pipe, 9... Traveling direction of ERW, 6... Eddy current flaw detection human contact detector, 10a~10x... Temperature pattern detector, 11a~llx... Signal processing device, 12a~ 12
x... Mark reading image set/Sakano 7.13a~1
3X...Controller, 14...White paint marking device, 15...Striped mark, 16...Contact chip of high frequency omega contact device, ]7...Fluorescent paint marking device,
18...Striped mark, 21a-21x...Ultraviolet irradiator, 22...Compressed air sprayer for draining, 23...Warm air sprayer for forced drying of paint.

Claims (1)

[Claims] Upstream of the weld heat treatment equipment in the ERW pipe manufacturing process, markings are continuously made at positions at a predetermined angle in the circumferential direction from the weld on the ERW pipe, and the above-mentioned heat treatment guide is made using this mark as a position reference. In a position control method in which the heating device always correctly heats the bath contact part, a fluorescent light-emitting substance powder or a bright reflection substance powder is added to the marking paint to mark the marking, and when reading, the marking is irradiated with a light source corresponding to the added substance. A method for detecting a contact position of an ERW pipe, characterized by detecting a mark.