SU1748036A1 - Magnetographic inspection of welded joints - Google Patents

Abstract

This invention relates to magnetic tape testing and can be used to control the quality of welds. The purpose of the invention is to increase the reliability of control, achieved by recording magnetic information on two ferromagnetic tapes stacked on top of one another, the width of one of which is chosen equal to the arc length of the weld bead and placed in such a way that its edges coincide with the edges of the seam roller, read information simultaneously from two tapes, and the quality of the monitored compound is determined from the results of the reading. 4 Il. ate with

Description

The invention relates to magnetic tape testing and can be used to control the quality of welds.

A known method of magnetographic control consists in magnetizing a product together with a fixed field laid on its surface with a magnetic tape, and then variables, which are turned off at polarity, the opposite of a constant.

The disadvantage of this method is low reliability, since it is possible to detuning from the faulty defects

There is a method of magnetographic control, which consists in that the magnetic tape is magnetized to saturation before control, after which the tape

double down along its length with ferromagnetic layers inside

This method is characterized by the irrational use of the magnetic media, since no information is recorded on one of its halves.

A known method of magnetographic control, consisting in that a second tape, previously magnetized on a reference sample with a constant polarity field opposite to the working field, is superimposed on the working magnetic tape, is read simultaneously from both tapes.

The disadvantage of this method is that if the magnetization regimes of the reference sample and the controlled product do not coincide, the signals from the edges of the weld bead are not compensated

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ABOUT

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The closest in technical essence to the achieved result is a method of magnetographic control consisting in recording magnetic information on two ferromagnetic tapes stacked on top of each other with the subsequent reading of information simultaneously from two tapes

However, signals from the edges of the seam roller make it difficult to isolate the signal from a defect, which reduces the reliability of control.

The purpose of the invention is to increase the reliability of the magnetographic control of welded joints.

This goal is achieved by the fact that, according to the method of magnetographic control of welded joints, the magnetizing of a welded joint records magnetic information on two ferromagnetic tapes stacked on each other to read information simultaneously from two tapes and determine the quality of the welded joint by reading results one of the flax is chosen from the length of the arc of the roll of the weld weld and is placed in such a way that its edges coincide with the edges of the weld bead

Fig. 1 shows a general view of recording information on two tapes in Fig. 2 - "a waveform is obtained on the flaw detector screen when read from a wide tape in Fig. 3 - a waveform is obtained when reading with a narrow tape in Fig. 4 - a waveform is obtained when read together from two tapes

Two tape widths of tape 2-35 or 70 mm width of tape 3 equal to the arc length of the seam roller are magnetized to the controlled section of the welded seam of the product 1 After the field is turned off, information from the magnetic media is read off. magnetic information recorded on a wide tape, signals will be observed on the flaw detector screen (FIG. 2) A from the edges of the tape, B from

edges of the seam roller, C - from a defect. Reading information from a narrow tape receives on the screen signals from the edges of the tape G and signals from the defect E (Fig 3). Signals from the edges of the seam roller of the wide tape and signals from the edges of the narrow tape have different polarity. from two tapes (FIG. 4) they will compensate each other and will be observed on the flaw detector screen

- only signals from edges of wide tape E and signals from defect W

Example On a controlled section of a weld with a weld width of 12 mm and a height of 1.5 mm from a steel product of 3 s

6 mm thick base metal with a R seam, a through defect 1 mm in diameter, which was obtained by drilling, laid two magnetic tapes with a wide (35 mm) tape and a seam of the edge of the narrow tape combined with

Koa Mishva The width of the narrow tape was equal to the length of the arc of the seam roller L 12 5 mm

The product was magnetized by a permanent electromagnet (magnetizing current b A) After the electromagnet was turned off, information was read simultaneously from two tapes on the MD-11G detector The signals from the edges of the wide tape and the signal from the edges of the seam roller were not on the screen

was observed

Claims (1)

The use of this method allows to increase the reliability of the magnetographic control of welded joints. Method of magnetographic control of welded joints, in case of magnetization of the welded joint, magnetic information is recorded on two ferromagnetic tapes, stacked on each other, information is read simultaneously from two tapes and the quality of the controlled compound is determined from the reading results, characterized in that in order to increase the reliability of checking the width of one of the strips is chosen equal to the arc length of the weld bead and is laid so that its edges coincide with the edges of the weld bead 7