Services

Magnetic Particle Inspection

Liquid penetrant inspection and testing of stainless steel pipes

Magnetic particle inspection, also frequently referred to as MPI testing or Magnaflux inspection, identifies surface flaws in metal products that can be magnetized. This nondestructive test is best for forgings, castings, weldments, fasteners, and machined or stamped parts. The magnetic particle testing services at Laboratory Testing Inc. are available for raw materials, semi-finished materials such as castings and forgings, finished materials, and welds.

LTI MPI Capabilities

Test Summary

MPI Testing Methods – dry powder and wet fluorescent magnetic particle testing
Size Limitations – products up to 12 feet in length
Product Requirements – Magnetization capability
Test Supplies – Magnaflux brand
Certified MT Level 2 inspectors evaluate all test results
Two ASNT-certified MT Level 3 examiners full-time on staff

Standards

ASTM E1444
ASTM E709
MIL-STD-1949
MIL-STD-271 and NAVSEA T9074-AS-GIB-010/271
MIL-STD-2132
AMS 2300 Series (Material Cleanliness)
Boeing BSS 7040 and HP6-5
Pratt & Whitney MPM
GE Aerospace P3TF48
Bell Helicopter BPS 4075

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The MPI Testing Process

For MPI testing using the wet fluorescent method, the test operator spreads fine iron oxide particles with high magnetic permeability over the surface of a test piece as it is magnetized. The magnetic particles use a wet suspension of a petroleum-based carrier. Discontinuities such as cracks, laps, and seams in the material distort the surrounding magnetic field, causing the particles to be drawn to and collected in these areas for a visible indication of the defect.

A trained nondestructive testing technician interprets any indications observable during the magnetic particle inspection. The magnetic field can use either direct current (DC) circuits or alternating current (AC) circuits – AC circuits produce fields confined to the test sample’s near-surface and help find surface cracks; DC circuits provide magnetic fields that penetrate a shallow distance into the test sample and help find discontinuities below the surface.

Each MPI test piece is inspected in two opposing directions to find defects in all locations (e.g., head shot, central conductor shot). Performing the test in each direction requires the full magnetic particle inspection process (spray, magnetize, examine for defects) to be performed multiple times to evaluate the entire part. After the MPI Inspection finishes, all parts are run through a demagnetizer to remove or reduce the residual magnetism to within the allowable limits of the applicable specification. LTI uses ultrasonic vapor degreasing units to efficiently clean parts before and after inspection.

Laboratory Testing has NADCAP accreditation for MPI testing. Certified Level 2 inspectors evaluate all MPI test results. LTI has two full-time ASNT-certified MT Level 3’s on staff to assist the Level 2 inspectors. Each order has a laboratory test report showing the accreditation, applicable standards, and detailed results. MPI by the wet fluorescent or dry method is performed according to MIL-STD-1949, MIL-STD-271, and ASTM E 1444, while wet fluorescent magnetic particle inspection adheres to MIL-STD-2132. PRI Nadcap also accredits the test.

LTI Is Your MVP for MPI Testing

MPI is just one type of nondestructive test performed at Laboratory Testing Inc. NDT methods allow materials and products to be tested or inspected without damage. LTI also provides liquid penetrant, ultrasonic, radiographic (X-ray) and visual inspection, and hydrostatic pressure testing.

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Laboratory Testing Inc. has the capacity and capabilities to handle all your material testing needs in a single location. Since 1984, we’ve aided customers worldwide with accurate nondestructive testing and precise material lab services. Request a quote or contact us today to see how our industry-leading turnaround times can keep your mission-critical approvals moving forward.

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