JPS5928655A - Flaw detection method of metallic material - Google Patents

Abstract

PURPOSE:To detect automatically and continuously flaws with high reliability, by disposing an electrode which is applied with voltage oppositely to a metallic material and detecting the electric discharge pulses generated between the metallic material and a power source. CONSTITUTION:One end of a traveling metallic wire rod 10 is grounded and a DC voltage E is applied from a DC power source 14 to an annular electrode 12 which encloses the wire rod 10 apart therefrom. If there is a flaw such as a projection or dent on the surface of the traveling wire rod 10, the electric field between the electrode 12 and the wire rod 10 increases in the vertex of the projection, the edge of the dent, etc.; therefore, a partial discharge is generated between the flaw part and the annular electrode. Then a pulse current flows to a capacitor 16 and a pulse voltage Ep is detected by a pulse detector 20. The presence or absence of the flaw in the wire rod 10 and the position thereof are detected from the traveling speed of the wire rod 10 by the pulse detector 20 in the above-mentioned way.

Description

[Detailed description of the invention] I) Protrusions on the surface of metal materials such as rugs, scratches on Komiji Temple? It concerns a method of detection.

enamel&! If there is a protrusion on the surface of the conductor wire used for electric wires such as 7'1, the insulation grade will be completely applied to the surface of the conductor, and the protrusion will protrude from the insulation, resulting in poor electrical characteristics such as dielectric strength. S・L
'-' If the lifting platform has a significant percentage, the insulation will break down and it will become unusable. In addition, if there is a dent in the metal wire strip, the material may break when it is further drawn or rolled.In order to detect scratches in the metal wire material, conventional methods have been to visually or microscopically inspect the metal wire. It was difficult to obtain high-quality metal materials because it was time-consuming and unreliable because the method required observing the metal materials.

SUMMARY OF THE INVENTION It is an object of the invention to provide a method by which flaws in metal materials can be continuously and reliably detected automatically.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 schematically shows a flaw detection method for metal materials according to the present invention, and in the embodiment of FIG. An annular electrode 12 that is grounded and surrounds the entire wire 10 at intervals.
The same current voltage El is applied from the DC power supply 14 to A capacitor 16 is provided in parallel with this DC type @, 14, and also converts the pulse current flowing through this capacitor into a pulse voltage. C') is provided with a resistor 18VC pulse detector 20 connected in series with the capacitor 16. Note that in FIG.
DC power supply L4VC@ to prevent the pulse current of 6 from flowing in.
The field impedance provided in the row is 0 and 1, the surface of the running gold h4 proboscis material 10 + M + VC If there are scratches such as protrusions or dents, annular ' Because the electric field between i2 and the metal phase-resistant lO becomes stronger, a partial discharge occurs between this toothed part and the annular electrode.As a result, a pulse current flows through the capacitor 16, causing /
One pulse voltage Ep is detected by the CC soot generator 201't. In this way, the pulse detector 20 can be configured to detect the south peak and seventh position of the scratch on the metal leg lO from the running speed of the metal leg lO. , In the above hr2 embodiment, a DC voltage was applied to the ring-shaped city, the coffin was 12 K, or a father current' turtle pressure could also be applied, and a partial discharge occurred in this place. From the crying phase to the extent of the wound #
(The size of the protrusion, the depth of the indentation) You can hear the sound 0 Next, let's take a specific example of the non-inventive Q-Fu ＼ゼ, and an annular shape with an inner diameter of 50 + + + m on a copper wire between outer diameters 0 and 2... , Miscellaneous 2 (6) - When the copper wire has a spheroid-shaped protrusion 24 as shown in Fig. 2, the size of the protrusion and partial discharge 1 start voltage 1 pressure (actual value)' is 1 ton n. Shown in the same table. In addition, in this table, a is the diameter of the spheroid, C is the 7-ruled abbreviation, and metal 1 ()
The voltage limit of the undamaged part was 3KV/mm.

No surface projection 1650 0.1 440 0.5 450 0.8 500 1.0 600 2.0 880 3.0 1050 5.0 1300 IQ 1480 Surface force of upper mouth C) As is clear from % a/C The smaller the diameter of the protrusion, the smaller the diameter of the protrusion, the more likely it is that partial discharge will occur.

FIG. 3 shows an example in which the gold-strewn material is a running metal strip lO', and in this example, the plate electrode 12'
The embodiment is the same as the embodiment of FIG. 1, except that is used. If the metal strip is made of iron plate with a thickness of 0.5, the protrusion sound at a/c = 5.01 in the previous table can be detected by setting the width of the narrow side to 2.5 KV/mm. Kade@ta○ In addition, in the embodiments shown in FIGS. 1 and 3, the metal molybdenum and the electrode are in an air atmosphere, but SF 41 + is used instead of air.
A gas atmosphere such as Freon 113 may be used, and in this case, by applying a voltage 2.5 times higher than that in the case of air, the root circumference of the wound (vt LC, It becomes possible to detect unbalanced values.

Uninventively, if Ctl is above, C9 has scratches on the metal material?
There is a spark that runs continuously over its entire length and can be detected in 18 square meters.

[Brief explanation of the drawing]

Fig. 1 is a shelf showing an embodiment of the present invention, a schematic system diagram, and a second
The figure is an enlarged sectional view of a protruding scratch, and FIG. 3 is a schematic system diagram showing another embodiment of the present invention. 12°12'...
... Electrode, 14 ... DC galvanic corrosion, 16 ... Capacitor, 20 ... Pulse detector. 1st m n2 ray 1/i3 10'

Claims (2)

[Claims] (1) A method for detecting flaws in metal materials, characterized in that an electrode to which a voltage is applied is arranged opposite to the metal material, and flaws are detected from discharge pulses generated between the metal material and the electrodes. . (2) Former HCC metal material gold lI 4 wins %W Flaw detection method for Kintei materials described in Range Steel 1 Man.