JPH0136122Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a magnetization device for detecting fillet welds, for example, used for magnetic particle flaw detection of fillet welds in oil storage tanks and the like.

Generally, after welding steel plates, etc., a portable pole-to-pole type magnetization device is used to inspect for flaws in and around the welded portion. 1 to 4 show the iron core of a conventional portable pole-to-pole type magnetizing device. The upper parts of these cores are I-shaped (Figures 1 and 4), H-shaped (Figure 2), and X-shaped (Figure 3), and Figure 1 shows the two legs a and b. 2 to 4 are quadripolar with four legs, and are made of a soft magnetic material such as a silicon steel plate. An excitation coil (not shown) is wound around the upper core or the leg core.

When these iron cores are placed on the top surface of the flaw detection part, magnetic particles are scattered on the flaw detection surface, and the excitation coil is energized. If there is a defect on or near the surface of the flaw detection part, leakage magnetic flux is generated and the magnetic particles reach the surface. It aggregates and adsorbs, and the defect shape appears as a magnetic particle pattern. This magnetic powder pattern is observed to determine whether there are any defects, and when detecting fillet welds, the upper core is This obstructs the observation, forcing you to avoid it by observing diagonally from the left and right or up and down.
This was a cause of misjudgment.

Furthermore, the accuracy of detecting defects is greatly influenced by the relationship between the direction of the defects and the direction of the magnetic field in the steel part. The best detection condition is when a magnetic field is applied in a direction perpendicular to the longitudinal direction of the defect, and it becomes difficult to detect the defect when the direction of the defect and the magnetic field are parallel.

In the two-pole magnetization device shown in Figure 1, legs a and b
Since a magnetic field can only be generated in the direction that connects the two, the direction of the magnetization device must be changed at least twice for one flaw detection surface when performing flaw detection.
As a result, work efficiency is poor. The four-pole magnetization device shown in FIGS. 2 to 4 generates an alternating magnetic field or a rotating magnetic field, and attempts to detect all defects on the test surface at once without changing the orientation of the magnetization device. However, defect patterns and pseudo-defect patterns appear in all directions, making it difficult to distinguish them.

The object of this invention is to provide a magnetization device for detecting fillet welds, which eliminates these drawbacks, facilitates observation of the surface to be detected, and improves the efficiency of magnetic particle detection work.

The magnetization device for detecting fillet welds of this invention consists of a channel-type core and two angles installed perpendicularly to each leg of the channel-type core with one leg magnetically insulated from the channel. The iron core is composed of a shaped iron core. A coil is wound around each of these cores. The coils wound around the angled core are each wound with coils that produce magnetic poles in the same direction. Further, a switch is connected to each coil, and by operating this switch, magnetic fields can be generated in two directions, perpendicular and parallel to the fillet weld.

This idea will be explained using examples.

Figures 5 to 7 show an embodiment of the magnetization device for detecting fillet welds of this invention. In Figure 5, A is a plan view of the core, B is a front view, and C is a side view. 6 is a perspective view.

The core of the magnetizing device shown in FIGS. 5 and 6 is composed of angle-shaped cores 1a and 1b and channel-shaped core 2, and is made of a soft magnetic material such as a silicon steel plate. One leg of each of the angle cores 1a and 1b is fixed to the leg of the channel core 2 with a fixing pin 3, respectively. This fixing pin 3 magnetically insulates the angle cores 1a, 1b and the channel core 2. Coils 4a, 4b, 5 are wound around these iron cores 1a, 1b, 2. Coils 4a, 4 wound around angle-shaped iron cores 1a, 1b
b are wound so that magnetism occurs in the same direction.

This iron core is placed on the flaw detection section as shown in FIG. That is, each end of the angled iron core is brought into close contact with the bottom plate 8 and side plate 7 of the steel plate. Next, by scattering magnetic particles on the flaw detection section and applying an excitation current to each coil, it becomes possible to determine the presence or absence of defects based on the magnetic particle pattern. The inter-core space 6 is large enough to observe the flaw detection surface.

FIG. 7 shows the connection of the coil,
C ₁ and C ₂ indicate coils 4a and 4b wound around angle-shaped iron cores 1a and 1b, respectively, and C ₃ shows coil 5 wound around channel-shaped iron core 2. Note that in FIGS. 6 and 7, N and S indicate the polarities of the magnetic poles of the coil. As shown in FIGS. 6 and 7, the coils of the angled cores 1a and 1b are wound so that their magnetic poles are in the same direction. In FIG. 7, _S1 is a switch connected in series to coils _C1 and _C2 , and _S2 is a switch connected in series to coil _C3 .
Single-phase power terminals V ₁ , V ₂ are connected through these switches.
The configuration is such that excitation current is supplied to the coil from the coil.

In Figures 6 and 7, switch _S2 is closed,
When switch S ₂ is opened and excitation current is applied to coils C ₁ and C _2, magnetic poles N and S in the same direction are generated in angle cores 1a and 1b, respectively.
The magnetic field from the N pole to the S pole of a, 1b is the fillet weld part 9
occurs in a direction perpendicular to . When switch S ₁ is opened and switch S ₂ is closed, excitation current is applied to coil C ₃ , magnetic poles are generated at both ends of channel core 2 and a magnetic field parallel to fillet weld 9 is generated.

As mentioned above, the magnetization device for detecting fillet welds of this invention has a wide air space between the iron cores, making it easy to observe the surface to be tested, eliminating the risk of misjudgment as in the conventional case, and furthermore, Magnetic fields in two directions, perpendicular and parallel to the fillet weld, can be obtained by simple operation, so there is no need to move the magnetization device across the weld, and the excitation range is large, so the effective flaw detection range is also widened. It contributes to improving work efficiency and has a great practical effect.

[Brief explanation of the drawing]

Figures 1 to 4 are perspective views of conventional iron cores;
Figures 5 to 7 show an embodiment of this invention, in which Figure 5 A is a plan view of the core, B is a front view of the core, C is a side view of the core, and Figure 6 is a perspective view of the core. figure,
FIG. 7 is a wiring diagram of the coil. 1a, 1b...Angle type core, 2...Channel type core, 3...Fixing pin, 4a, 4b, 5...
... Coil, 6 ... Space between iron cores, 7 ... Side plate of steel plate, 8 ... Bottom plate of steel plate, 9 ... Fillet weld, C ₁ ,
C ₂ , C ₃ ... Coil, S ₁ , S ₂ ... Switch, N,
S...Polarity of the iron core.

Claims (1)

[Scope of utility model registration request] a channel-shaped core; two angle-shaped cores each of which is attached vertically to each leg of the channel-shaped core with one leg magnetically insulated from the channel; and wound around the channel-shaped core; a coil, a coil wound around the angle core to generate magnetic poles in the same direction in each angle core, and a switch connected to each coil, and by operating the switch, A magnetization device for detecting fillet welds, which is characterized by generating magnetic fields in two directions, perpendicular and parallel.