Trent Steffen: 1-780-821-9105

Disadvantages

Some Disadvantages of the Magnetic Particle method of Non-Destructive Examination are:

• It is restricted to ferromagnetic materials - usually iron and steel, and cannot be used on austenitic stainless steel
• The method cannot be used if a thick paint coating is present
• Spurious, or non-relevant indications, are probable, and thus interpretation is a skilled task
• Some of the paints and particle suspension fluids can give a fume or fire problem, particularly in a confined space

Advantages

Some Advantages of the Magnetic Particle method of Non-Destructive Examination are:

• It is quick and relatively uncomplicated
• Fast NDT method, indications are visible directly on the objects surface when particles are applied.
• Can detect both surface and near surface defects/indications, and these are the most serious ones as they concentrate stresses
• The method can be adapted for site or workshop use
• Very portable when used with battery powered equipment
• It is inexpensive compared to other NDT Techniques and helps prove up other NDT Techniques when indications are found
• Large or small, irregular shaped objects can be examined
• Elaborate pre-cleaning is not necessary

What is Magnetic Particle Inspection (MPI)?

Magnetic Particle Inspection (MPI) is a nondestructive testing method used for defect detection. MPI is commonly know by other names as well Mag Particle, Magna fluxing, Black Lighting. MPI is fast, versatile and relatively easy to apply, and part surface preparation is not as critical as it is for some other NDT methods. These characteristics make MPI one of the most widely utilized nondestructive testing methods in the world. The method is used to inspect a variety of product forms including castings, forgings, machined products and weldments. Many different industries use magnetic particle inspection for determining a component's fitness-for-use. Some examples of industries that use magnetic particle inspection are the structural steel, automotive, petrochemical, power generation, and aerospace industries. Underwater inspection is another area where magnetic particle inspection may be used to test items such as offshore structures and underwater pipelines.

MPI uses magnetic fields and small magnetic particles (i.e.iron filings) to detect flaws in components. The only requirement from an inspectability standpoint is that the component being inspected must be made of a ferromagnetic material such as iron, nickel, cobalt, or some of their alloys. Ferromagnetic materials are materials that can be magnetized to a level that will allow the inspection to be effective.

If the specimen has discontinuity, the magnetic field flowing through the specimen is interrupted and leakage field occurs. Finely milled iron particles coated with a dye pigment are applied to the specimen. These are attracted to leakage fields and cluster to form an indication directly over the discontinuity. The indication is visually detected under proper lighting conditions. Then indication is then determined to be a relevant or non-relevant indication by a qualified MPI inspector.

​What is NDT?

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Non-destructive testing (NDT) is a wide group of analysis techniques used in science and industry to evaluate the properties of a material, component or system without causing damage. The terms Non-destructive examination (NDE), Non-destructive inspection (NDI), and Non-destructive evaluation (NDE) are also commonly used to describe this technology. Because NDT does not permanently alter the article being inspected, it is a highly valuable technique that can save both money and time in product evaluation, troubleshooting, and research. Common NDT methods include ultrasonic (UT), magnetic-particle (MPI), liquid penetrant (LPI), radiographic (RT, XRAY), remote visual inspection (RVI), eddy-current testing (ET), and low coherence interferometry. NDT is commonly used in forensic engineering, mechanical engineering, electrical engineering, civil engineering, systems engineering, aeronautical engineering, medicine, and art.

Mag-Spec Inspection Services Ltd.