Ndt Magnetic Particle Testing Pdf

Consider the case of a bar magnet. Please help improve this article by adding citations to reliable sources. The use of an electromagnet to find subsurface indications is difficult. To identify a leak, ferrous particles, either dry or in a wet suspension, are applied to a part.

There are several types of electrical currents used in magnetic particle inspection. Using a similar machine, a U.

Indirect magnetization occurs when no electric current is passed through the test object, but a magnetic field is applied from an outside source. Any place that a magnetic line of force exits or enters the magnet is called a pole. After the component has been magnetized, iron particles, either in a dry or wet suspended form, are applied to the surface of the magnetized part. This cluster of particles is much easier to see than the actual crack and this is the basis for magnetic particle inspection.

Editing help is available. The magnetization is normally done with a high current pulse that reaches a peak current very quickly and instantaneously turns off leaving the part magnetized. Please help improve this section by adding citations to reliable sources.

This requires special equipment that works the opposite way of the magnetizing equipment. Direct magnetization occurs when the electric current is passed through the test object and a magnetic field is formed in the material. To demagnetize a part, the current or magnetic field needed has to be equal to or greater than the current or magnetic field used to magnetize the part. If the magnet is just cracked but not broken completely in two, a north and south pole will form at each edge of the crack.

Navy technician sprays magnetic particles on a test part under ultraviolet light. Opinions expressed are those of the authors and not necessarily those of the National Science Foundation. For a proper current to be selected one needs to consider the part geometry, material, the type of discontinuity one is seeking, and how far the magnetic field needs to penetrate into the part. After the part has been magnetized it needs to be demagnetized. This section does not cite any sources.

Magnetic Particle Inspection

International Atomic Energy Agency. The magnetic field exits the north pole and reenters at the south pole.

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From Wikipedia, the free encyclopedia. If iron particles are sprinkled on a cracked magnet, the particles will be attracted to and cluster not only at the poles at the ends of the magnet, but also at the poles at the edges of the crack.

Magnetic Particle Inspection

The piece can be magnetized by direct or indirect magnetization. This article needs additional citations for verification.

Magnetic particle inspection

Nondestructive Testing

Magnetic particle inspection

When a bar magnet is broken in the center of its length, two complete bar magnets with magnetic poles on each end of each piece will result. If any defects on or near the surface are present, the defects will create a leakage field. Please help improve it or discuss these issues on the talk page. This article has multiple issues.

The process puts a magnetic field into the part. The current or magnetic field is then slowly reduced to zero, leaving the part demagnetized. Wikimedia Commons has media related to Magnetic particle inspection. The particles will be attracted and cluster at the flux leakage fields, my heart will go on piano notes pdf thus forming a visible indication that the inspector can detect. The first step in a magnetic particle inspection is to magnetize the component that is to be inspected.

This article is in list format, but may read better as prose. These are attracted to an area of flux leakage and form what is known as an indication, which is evaluated to determine its nature, cause, and course of action, if any. In other projects Wikimedia Commons. It has a magnetic field in and around the magnet. It is dangerous to use kerosene or mineral spirits as a carrier due to the risk of fire.