JPH0284216A - Abnormality diagnosis method for welded shape of metallic strip - Google Patents

Abstract

PURPOSE:To prevent generating flaws on end surfaces of the steel plate and breaking of the steel plate by detecting the shape abnormality on the welded part of the strip quantitatively by a meandering straightening device for the strip and comparing the detected value with a set value to diagnose the shape abnormality of the welded part. CONSTITUTION:The strip 2a is welded with the strip 2b by a lap resistance heating welding machine 3, the welded strip is conveyed to the meandering straightening apparatus (CPC) 4. Through the output from a strip position deviation meter 5, a cylinder 4c operated by the CPC4 to rotate the CPC body centering around the point O and by tilting rollers 4a, 4b, the meandering of the strip is straightened to return to the line center. When the operated results from detected values through the strip position deviation meter 5 and cylinder position detector 4d exceeds each set value, respectively a line decelerating command is outputted or an installation inspecting command is outputted. By this method, the welding abnormality is detected quantitatively to reflect it to operate in early stage to improve the productivity.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for diagnosing an abnormality in the welded shape of a metal strip, and more specifically, a method for quantitatively detecting an abnormality in the shape of a welded part (dog-shaped). Regarding the diagnostic method that made it possible.

[Prior art] In general, in the production and processing line of cold rolled steel sheets, the m
Off-center handling of the conveyor line can have a negative impact on operations and quality.

For example, the line speed may need to be reduced because the steel plate snakes along the line, or the edges of the steel plate may come into contact with related equipment, causing scratches on the edge of the steel plate, or in severe cases. It may break.

Therefore, in general, meandering correction (CenL) is performed on the line as appropriate.
A control device (hereinafter referred to as CPC) is installed to control the steel plate so that it is conveyed through the center of the line.

[Problems to be solved by the invention] WI! If Fl is welded and the welded shape is bad and the planar shape of the welded part becomes dogleg-shaped, the CPC control limit will be exceeded and the situation will have a negative impact on operation and quality. may occur. No countermeasures have been taken in the prior art for defects in the planar shape of the welded portion that exceed this control limit.

On the other hand, the reason why the weld shape becomes dogleg-shaped is that the parallelism of the steel plate is out of order due to a decrease in the welding accuracy of the welding machine, or that the rear end of the leading steel plate and the tip of the trailing steel plate are pinched during welding. There may be an abnormality in the clamp pressure when overlapping. It is a well-known fact that if the amount of dogleg-shaped distortion can be detected, it can be corrected. However, there is no means to quantitatively detect the shape after welding, and it is difficult to detect flaws on the edge of the steel plate or damage the steel plate. Currently, problems such as breakage are occurring.

The present invention has been proposed to solve these problems, and an object of the present invention is to provide a method for diagnosing weld shape abnormalities in metal strips that detects the amount of dogleg-shaped distortion in the weld. be.

[Means for Solving the Problems] The present invention solves the above-mentioned problems, and provides a welding abnormality diagnosis method in a welding method in which the trailing end of a leading strip and the leading end of a trailing strip are overlapped and joined by heating and melting. The following method was adopted. In other words, abnormalities in the shape of the strip contact area are quantitatively detected using a strip meandering correction device, and the detected value is compared with a set value.
This is a method for diagnosing weld shape abnormalities.

[Function] According to the present invention, it is possible to quantitatively detect abnormalities in the shape of welded parts (in the shape of a square), so it is possible to correct the abnormalities at an early stage, and prevent the occurrence of flaws on the end faces of steel sheets and can prevent breakage.

[Example] FIG. 2 is an explanatory diagram of a line configuration in which the present invention can be carried out suitably. The strip 2a rewound by the 0 unwinding machine 1 is transferred to a superimposed resistance heating welding machine 3 (narrow rough bush seam welder). ) welds the strip 2b, and the welded strip is conveyed to the CPC 4 downstream of the welding machine 3.

Based on the output of the strip position deviation meter 5, the CPC 4 operates the cylinder 4c (shown in FIG. 4) to move the roller 4.
By tilting a and 4b, the strip is moved to the center of the line and the meandering of the strip is corrected. After that, the strip is transferred to the processing section (rolling, annealing, etc.)
6 and then wound into a coil by a winder 7.

When the strips 2a and 2b are welded by the welding machine 3 in the state shown in FIG. 3, the strips meander greatly as shown in FIG. 4 as they pass through the CPC 4. As a result, the strip deviates from the line center on the output side of the CPC 4, and the value of this deviation is output to the strip position deviation meter 5. FIG. 5 shows the dogleg weld of the strip attempting to pass through the CPC 4.

When the center of the strip and the center of the production line deviate from each other, the CPC4 rotates the main body of the CPC4 around point O using the cylinder 40, tilts the roller 48.4b, and returns the strip to the center of the line.

Il: Distance between the outer sides of rollers 4a and 4b I2 □ Distance between Niji cylinder 40 and line center ε : Output y of deviation meter 5 Output of Niji cylinder position detector 4d, so that the strip does not slip on rollers 4a and 4b When it comes to something.

If X is the distance between the center of the roller 48 and the point O, it is expressed as x=y×(g, l/I2□)−ε (+).

As a means of quantitatively detecting abnormalities in the shape of the welded part (dog-shaped), as shown in Fig. 6, the amount of strain (the amount of dogleg) h with respect to the standard length (for example, 5 m) of the strip before and after welding is measured. Define as follows.

h=Xsax-(X++Xn*+)/2
”-(2) Here, X n : Number of divisions when the strip is divided into equal parts before welding.

FIG. 1 shows the diagnostic flow of the present invention. y mentioned above
and ε are input into the signal board 8, and this value is led to the center locus calculator 9 to calculate X, and further 7 quantity calculators 11
Calculate Deku's prison.

This calculation result is set as a value by the operation abnormality discriminator 12, and (
For example, if the set value h1 is exceeded, a line deceleration command is output to the alarm panel 13.

In addition, the equipment abnormality discriminator 14 also compares it with a set value ha (for example, 15 mm), and if it exceeds the set value h2, an equipment inspection command mainly for the welding machine is output to the alarm panel 15. In this way, shape abnormalities in welded parts can be quantitatively detected and reflected in operations.

By applying the present invention to a continuous annealing line for ultra-thin plates, it has become possible to reduce strip breakage accidents by 48 hours/year.

Incidentally, in the meandering correction, the case where the center of the strip is made to coincide with the center of the line has been described, but it is also possible to maintain one end of the strip in the width direction at a predetermined position to prevent meandering. This is EPC (Edge Po
5ition Control), and the above (1
) instead of the formula, X = 3'' (g l / I2□) - ε + CC: shift setting amount.

[Effects of the Invention J] The present invention can quantitatively detect shape abnormalities after welding and reflect them in operations at an early stage, thereby making it possible to prevent the occurrence of flaws on the end face of the steel plate and breakage of the steel plate, thereby increasing productivity. It has an excellent effect on improving.

[Brief explanation of the drawing]

Fig. 1 is a diagnostic flow of the present invention, Fig. 2 is an explanatory diagram of a line configuration that can suitably carry out the present invention, Fig. 3 is an explanatory diagram of a strip welded in a dogleg shape, and Fig. 4 is an explanatory diagram of a strip welded in a dogleg shape. FIG. 5 is an explanatory diagram of the operation of the present invention, and FIG. 6 is an explanatory diagram of the definition of a square prison. l... Rewinding machine 2a... Trailing strip 2b... Leading strip 3... Welding machine 3a... Trailing electrode clamp 3b... Leading electrode clamp 3cm... Welding rolling wheel 4. ...CPC4a...Inlet roller 4b...Outlet roller 4C...Cylinder 4d...Cylinder position detector 5...Strip position deviation meter 6...Process section 7...-Rewinder 8...Signal manual board 9--Center locus calculator lO...Welding position detector 11...Kuno prison W unit 12...Operation abnormality discriminator 13...7 report board 14-・Equipment abnormality discriminator 1
5.-1 report board

Claims (1)

[Claims] 1. A method for diagnosing a welding abnormality in a welding method in which the rear end of a leading strip and the leading end of a trailing strip are overlapped and joined by heating and melting, comprising: a meandering correction device for the strip to correct the shape of the welded portion of the strip; A method for diagnosing welding shape abnormalities in metal strips, comprising quantitatively detecting welding shape abnormalities in metal strips and comparing the detected values with set values to diagnose welding shape abnormalities.