JPS60173462A - Flaw detecting method of ferromagnetic body using amorphous alloy magnetic powder - Google Patents

Abstract

PURPOSE:To improve detection sensitivity and detect a fine defect by using amorphous alloy powder 50% of which is amorphous as magnetic powder when detecting a defect part of a ferromagnetic body by a magnetic powder flaw detecting method. CONSTITUTION:Alloy consisting principally of, for example, iron, cobalt, nickel, copper, etc., is used as the amorphous alloy used as magnetic powder, and is manufactured by quenching the fused body of it at an about 10-10<6> deg.C/sec quenching speed or by vapor-deposition, sputtering, electrodeposition, or chemical plating. When a measurement is taken by X-ray diffraction, 50%, preferably, 80%, further preferably, 90% of it is amorphous. The use of this magnetic powder improves the detection precision extremely and a defective magnetic powder pattern is detected with a low detection current of about 130A, so this method provides economy.

Description

[Detailed description of the invention] The present invention relates to a flaw detection method for ferromagnetic materials using magnetic particles.

Magnetic particle flaw detection is generally known as a method for detecting defective parts (flaws) in ferromagnetic materials. When a current is applied directly or indirectly to a ferromagnetic material that has a defective part, that is, a magnetically discontinuous part, on its surface to magnetize the material, the leakage magnetic flux that appears near the defective part is detected. This is a method of detecting the defect position and shape of the ferromagnetic material by utilizing the phenomenon in which ferromagnetic powder is attracted to the location where this leakage magnetic flux exists.

This method is particularly sensitive for detecting linear surface defects.

As ferromagnetic powder (magnetic powder) materials used in conventional magnetic particle flaw detection methods, electrolytic iron, γ-ferric oxide, magnetic triiron tetroxide, etc. have been used up to now. However, when these magnetic particles are used, the detection sensitivity is low, and in order to accurately identify defective parts of the ferromagnetic material, it is necessary to apply a large current to strongly magnetize the ferromagnetic material. In order to improve this point, a method has been used in which magnetic particles are coated with fluorescent paint to increase detection sensitivity, but satisfactory sensitivity has not yet been achieved. In addition, in the conventional method using magnetic particles, the particle size is too small to detect minute defects, such as /~
There are problems such as the need to use magnetic powder having a particle size of approximately ioμ.

The present inventors completed the present invention as a result of intensive research to solve these problems and develop a magnetic particle flaw detection method with high detection sensitivity.

That is, the present invention provides a method for detecting defective parts of υ ferromagnetic materials by magnetic particle testing, which is characterized by using amorphous alloy powder in which at least go% is amorphous as magnetic particles. Regarding.

The amorphous alloy used in the present invention is made by rapidly cooling a molten alloy of an appropriate composition (for example, an alloy mainly composed of iron, cobalt, nickel, copper, etc.) at a cooling rate of about 10-10't1'/sec. X
An alloy in which at least 50%, preferably 10%, more preferably 9% or more of the alloy is amorphous when measured by line diffraction; such amorphous alloys include, for example, general Formula % Formula % (wherein νHL a metal selected from the group consisting of nickel, chromium, cobalt and vanadium or a mixture thereof sy is a non-metal selected from phosphorus, carbon and boron, or a mixture thereof 12 is aluminum, silicon , tin, antimony, germanium, indium and beryllium, or a mixture thereof 1aX b and C are each 60-90./θ-3θ under the condition that their sum is 100,
0. /~−〇 atomic percentage. ) is an amorphous alloy.

A specific example of this is Tokko Akira! ;j
-/9? ? The amorphous alloy described in No. A can be praised.

In the present invention, among these amorphous alloys, it is preferable to use an amorphous magnetic alloy with a Curie point of roYO: or more, particularly ljOυ to 6θ0υ.

In the present invention, the ribbon or strip of the amorphous alloy is pulverized, for example, in a vertical vortex mill, and the particle size is θ, oi ~
100μ, especially 0. −~Aθμ powder and use this as magnetic powder. If necessary, these amorphous alloy powders may be coated with a coloring agent or a fluorescent agent.

In addition, the ferromagnetic material to be inspected for defective parts in the present invention is:
Examples of ferromagnetic metal materials include iron, carbon steel, silicon steel, and the like.

Further, the ferromagnetic material may be in the form of any raw material such as a plate, or may be in the form of a product.

How to detect defects in ferromagnetic materials using amorphous alloy powder JI8 CkO! This can be carried out by the detection method described in Ajt. In other words, the powder of an amorphous alloy that has been dried while magnetizing the ferromagnetic material, or is suspended in a liquid such as water, is sprinkled on the ferromagnetic material to be examined. By observing the magnetic particle pattern, the presence, location, type, etc. of the defective magnetic particle pattern can be confirmed, and the defect location and degree of the defect in the ferromagnetic material being tested can be detected.

The test specimen can be magnetized by passing a current directly through the specimen (axial current method, right angle current method, blond method), or by passing a current through a conductor passed through a hole in the test specimen ('fIL flow penetration method). A method in which a magnetic substance is inserted into a coil and current is passed through the coil (coil method), and a method in which an induced current is passed through a test object by applying alternating magnetic flux to a magnetic material passed through a hole in the test object to magnetize it (magnetic flux penetration method) ), and a method in which a test object or a part to be tested is magnetized between one pole of an electromagnet or a permanent magnet (pole-to-pole method). The current applied for magnetization may be direct current, alternating current, impact type, or current.

In addition, the energization time is 3 to 10 seconds for the continuous method, and % to 10 seconds for the residual method.
/second is appropriate.

In the present invention, since non-+1'l alloy powder is used as the magnetic powder, the detection sensitivity is lower than when conventionally known magnetic powder is used. It is economical because it can detect In the present invention, the strength is comparatively 11 compared to the case where conventionally known magnetic powder is used. That is, even if magnetic powder with a large particle size is used, the detection sensitivity is good, and therefore, there is an advantage that even minute defects can be easily detected.

The present invention will be explained in more detail below with reference to Examples.

Example/Amorphous alloy powder ioy with a particle size of 6 to 30 μ obtained by powdering an amorphous alloy having a composition of Fe12”i5aMo4BH+ (atomic %) in a vertical vortex mill is suspended in 1 liter of water. Next, A2 of the A type standard test piece (electromagnetic soft iron plate JIS O-koma θda) specified by JIS G-Oj-Aj.
−7/lo is s, 2tc is pu0tsu(yoxlθ×go
), and applying current to the specimen for ~S seconds using the current penetration method to magnetize the specimen, spraying the suspension onto the specimen.
The specimen was magnetized.

Observe the defective magnetic particle pattern of the formed test piece, and check the JIS a
- The defective portion of the test piece was detected based on ozbzK. The lowest detected current at this time was 13θA.

Comparative Example 1 A procedure was carried out in exactly the same manner as in Example 1, except that black magnetic powder (trade name: MRB-133 manufactured by Electronic Magnetic Industry ■) with a particle size of ~3μ was used instead of the amorphous alloy powder as the magnetic powder in Example 1. Magnetic particle flaw detection was performed. The lowest detected current at this time was /AθA.

Applicant: Mitsui Petrochemical Industries, Ltd. Agent Kazu Yamaguchi

Claims (1)

[Claims] (1) A method for detecting defective parts of a ferromagnetic material using a magnetic particle flaw detection method, characterized in that an amorphous alloy powder having at least an amorphous SO% is used as the magnetic particle. (21) The method according to claim 1, wherein the amorphous alloy is an amorphous magnetic alloy having a single Curie point of SOυ or more.