openPR Logo
Press release

Magnetic Particle Inspection (MPI) - The Basics

05-02-2018 09:31 AM CET | Industry, Real Estate & Construction

Press release from: Nexxis

Magnaflux MPI Yoke

Magnaflux MPI Yoke

Magnetic particle inspection (MPI) is a non-destructive testing (NDT) method that is used primarily for detecting surface or near-surface defects in ferromagnetic materials.

The technique emerged first emerged in the 1920s and followed the recognition of X-ray technology as a viable testing method for inanimate materials. Radiography had been found to be extremely useful for detecting defects that were below the surface or deeper inside the component, but industry needed a reliable and cost-effective solution for locating surface flaws in large quantities of machine and structural parts - and hence MPI was developed.

MPI is now one of the most widely used NDT methods and is used to inspect a variety of products across many different industries including mining, structural steel, automotive, marine, aerospace, underwater inspection, power generation and oil & gas.

The basic test method of MPI involves the application of magnetic field either externally or by applying electric current through the material under test, and then applying very fine magnetic particles (eg iron oxide particles between 0.125 and 60 microns) to the test surface either in a dry powder form (non fluorescent) or in a liquid containing a magnetic powder suspension. The liquid methods can either be fluorescent or non-fluorescent.

In the dry method, particles that have been chemically dyed to provide a clear contrast on the test surface are applied with a squeeze bulb or spray gun. The dry method gives improved sensitivity for detecting sub-surface flaws.

In the wet method, the particles are suspended in an oil or water-based liquid. When the wet method is used, operators need to add conditioners as well as a wetting agent and corrosion-inhibitors. The wet method gives improved sensitivity for detecting very fine surface flaws.

Flux lines of the magnetic particles will distort at the site of a surface or near sub-surface discontinuity, and this distortion in the induced magnetic field causes leakage of the magnetic fields. The magnetic particles are attracted by the surface field and adhere to the edges of the defect, giving a visible indication of its shape and size.

Here are some of the basics about MPI testing.

• It is only effective on ferromagnetic materials which include most of the iron, nickel and cobalt alloys. It cannot be used on non ferrous parts such as austenitic stainless steel, brass, copper, aluminium, titanium or any of the precious metals.
• It is used to locate fine, shallow surface discontinuities which are invisible to the naked eye, without causing any harm to the component itself.
• It is quick, relatively uncomplicated and highly sensitive.
• Surface preparation is not as critical as for some other NDT methods.
• It can be done either in a workshop or on site on items that are in service.
• Both large and small objects can be examined using MPI.
• It is inexpensive compared to other more sophisticated quality assurance methods such as radiography.
• It is used to test for linear indications (ie those which are at least three times as long as they are wide L=3 x >W).
• In some instances, MPI can also work through layers of contaminants and/or coatings.
• It is highly effective for testing high volumes of products at speed.

MPI does have limitations however. As mentioned earlier, it can only be used on ferrous materials and to be fully effective, the direction of the magnetic field has to intercept the major dimension of the discontinuity. It is not always effective on parts that have complex surface geometry.
Care must be also taken to avoid burning or arcing of the surface of the test part at the points of electrical contact and it is often necessary to demagnetise the test part once inspection is complete.

It is crucial that the inspectors know the advantages and disadvantages of each method as well as the different types of magnetising currents that can be used, and it is advantageous to source technical equipment from a supplier who understands the industry so that the right choices are made from the outset.

Nexxis is a preferred supplier of NDT and remote visual inspection solutions to all major industries in Australia, with a reputation for delivering cost-effective and tailored solutions. The Nexxis team works closely with clients to find the most relevant and practical testing solutions which add value to their bottom lines, and if you are interested in benefiting from their genuine commitment to customer service, give them a call on 08 9418 4952 or visit

12/55 Erceg Road
Yangebup WA 6164

Tel: +61-8-9418 4952

Press Contact
Debbie Smetherham

This release was published on openPR.

Permanent link to this press release:

Please set a link in the press area of your homepage to this press release on openPR. openPR disclaims liability for any content contained in this release.

You can edit or delete your press release Magnetic Particle Inspection (MPI) - The Basics here

News-ID: 1035691 • Views: 518

More Releases for MPI

Plastic Magnet Market Growth & Key Business Strategies by Leading Industry Playe …
This report studies the global Plastic Magnet Market size, industry status and forecast, competition landscape and growth opportunity. This research report categorizes the global Plastic Magnet Market by companies, region, type and end-use industry. Global Plastic Magnet Market report has been combined with a variety of market segments such as applications, end users and sales. Focus on existing market analysis and future innovation to provide better insight into your business. This
Toxicology Services Market 2018 | Key Players: Labcorp, Envigo, MPI Research
A new business intelligence report released by HTF MI with title “Pakistan Toxicology Services Market Research Report 2018” that targets and provides comprehensive market analysis with future prospects to 2023. The analysts of the study have garnered extensive research methodologies and data sources (i.e Secondary & Primary Sources) in order to generate collective and useful information that delivers latest market undercurrents and industry trends. Request Sample Report @: If you
Myocardial Perfusion Imaging (MPI) Testing Market Poised to Expand at a Robust P …
Myocardial perfusion imaging is an imaging device which work non-invasively to show the blood flow, myocardial perfusion imaging also known as nuclear cardiology test. The main function of this imaging to show the blood flow to muscle of heart or myocardium and to identify the absence or presence of CAD (coronary artery disease). Myocardial perfusion imaging show 3D image. Myocardial perfusion imaging two technique, such as PET (positron emission tomography)
Global Lithium-Ion Battery Separator Market Research Report 2017 - Toray, Celgar …
Qyresearchreports include new market research report Global Lithium-Ion Battery Separator Market Research Report 2017 to its huge collection of research reports. The new report in’s market intelligence repository presents readers with a comprehensive evaluation of the global Lithium-Ion Battery Separator market. Each aspect of the global Lithium-Ion Battery Separator market is assessed in thorough detail in the report in order to provide a 360-degree review of the market’s workings for
Apriso Redefines Manufacturing Intelligence with MPI 2.0
FlexNet Manufacturing Process Intelligence 2.0 delivers real-time visibility to improve manufacturing and supply chain performance PALM DESERT, CA – May 23, 2012 – Apriso, a leading provider of manufacturing software solutions, today announced availability of the second version of FlexNet Manufacturing Process Intelligence, MPI 2.0, a next generation solution for enterprise manufacturing intelligence. MPI 2.0 has redefined manufacturing intelligence by not only providing greater detailed visibility into production, machine and labor
MPI moves to new offices as springboard for growth
MPI Europe, specialist consultants to the finance industry, has moved their implementation and support office to new premises in Odiham, Hampshire. “This provides an excellent springboard for our continued expansion” said John Cant, Managing Director of MPI Europe. “We have seen increasing demand for our consulting services from both existing and new clients, despite challenging market conditions.” This new location has advantages over and above the additional space