Magnetic Particle Testing
We provide Magnetic Particle Inspections using dry or wet fluorescent iron particles. The magnetic particle inspection method is used for the detection of laps, cracks, inclusions, seams, and other flaws upon or just under the surface of an iron based material.
Certified Level II and III inspectors can perform your Magnetic Particle inspections at our or your location. We are able to create techniques, give pre-audit support, handle vendor audits, qualify your NDT inspectors and create an NDT program specific to your needs. We can even provide inspection staff augmentation and multi shift support during elevated workloads.
Common Uses for Magnetic Particle Testing
- Forged Parts
- Control Arms
- Structural Steel
- Generator Parts
- Lifting Devices
We have a host of options available for equipment. Wet horizontal bench, cable wrap, coil, prods or permanent magnets are available. Visible or fluorescent coated processes include HWDC, AC, and FWDC. Quality factors such as the sensitivity of the Magnetic Particle inspection process depends on the proper equipment selection.
As a general rule, parts inspected using the Magnetic Particle method should never remain magnetized after inspection. Parts containing a magnetic field can ultimately interfere with the function of a part.
Demagnetization of engine parts or general aircraft components is very important because magnetic fields can attract iron based grit which can increase wear. In addition, leaving a magnetic field in an aircraft parts could alter compass readings, causing incorrect navigation information. Often an aircraft will receive a weather-induced lightning strike. Demagnetizing or degaussing of antennas or adjacent panels must be performed with a DC magnetic yoke. We have years of experience performing these tasks.
Determining if a part has been sufficiently demagnetized after testing is performed by a Gauss meter. If the initial demagnetization procedure is not effective, additional processing may also be affected.
When you call on our services we want to provide the confidence required to remove any worries you may have. Our inspectors are professionally qualified and certified, our instruments are standardized and calibrated, and our inspectors are well versed on using quality indicator tools.
Magnetic Particle specifications: ASTM E 1444, ASTM 709, ASME Sec. V, NAVSEA 250-1500-1, NAVSEA T9074-AS-GIB-010/271, ASTM E-709 (E-138), MIL-STD-271, MIL-STD-2132, AMS 3041, AMS 3042, AMS 3043, AMS-3044, MIL-STD-2132, Boeing PS 21201, British Std. B.S. 4069. IS-16048-13, Pratt & Whitney PMC 1887, A-A-59230.
When your production begins to back up due to a broken mag bench, our doors are always open to accept your magnetic crack detection overflow work.
Magnetic Particle Training
The magnetic particle inspection method is used in detecting surface or slightly subsurface discontinuities in ferromagnetic (iron based) materials. Magnetic particle inspections are applicable to raw material, billets, finished materials, weldments, and in-use parts. Magnetic particle inspection is only applicable to ferromagnetic metals and steel alloys.
The principle behind Magnetic Particle inspection is to generate magnetic flux in a material, with lines of flux stemming along the material surface perpendicular to the potential defect. Where the flux lines approach a discontinuity, they move away from the part near the crack. Magnetizing the part will create North and South poles at the edges of a crack. These poles attract fine particles of magnetic material such as iron filings. Usually, these particles are iron oxide 20 to 30 microns large, and are suspended in a liquid vehicle that provides mobility for the particles to move over the surface of the test piece. This assists their movement to the leakage field. In some applications, a dry powder is used.
The iron particles can be red or black for inspection under white light, or they can be coated with a fluorescent substance that glows brilliantly under ultraviolet light (black light). The goal is to end up with as large a contrast as possible between the background and the crack indication.This technique allows for the surface defects that would require a magnifying glass to see as well as defects that would be missed by a visual inspection.
There are several methods of generating magnetic flux in the test part. A permanent magnet can be used but this method is difficult to be used accurately because of surface contact coupling and a deteriorating magnetic field strength. Modern inspection equipment generates a magnetic field electrically and this can be done directly or indirectly.
When using the direct method, a high amperage current passes through a test piece and magnetic flux is generated perpendicularly to the direction of current flow. In other words, the current should flow parallel to the inspection area. The indirect method must be used if the defect orientation makes the direct method incapable of finding the defect.
There are two ways to conduct the indirect method:
- Pass the current through a coil encircling the test piece.
- Pass the current through a yoke that that is adjacent to the test piece.
Naturally there is far more to learn in each of the Nondestructive Methods. We have yet to only glance at the surface foundations of each one, this page beingMagnetic Particle inspection. To know more or if you feel up to the challenge, NDT could be your next career move. Giving us a call is your next step toward becoming a certified NDT inspector. We look forward to your call!
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