Magnetic Particle Inspection(MPI/MT)

A group of analysis techniques used to evaluate the condition of materials, components, and assemblies without causing damage or altering their serviceability. NDE methods detect surface and subsurface flaws, measure wall thickness, characterize material properties, and assess the integrity of welds and joints. Common NDE methods include ultrasonic testing (UT), radiographic testing (RT), magnetic particle inspection (MPI/MT), liquid penetrant testing (PT), visual testing (VT), eddy current testing (ECT), and acoustic emission testing (AE).

An NDE method that uses penetrating radiation (X-rays or gamma rays) to produce an image of the internal structure of a component. The radiation passes through the material and is captured on film or a digital detector. Variations in material thickness, density, or internal flaws appear as contrast differences on the image. RT is effective for detecting volumetric flaws (porosity, inclusions, voids) and some planar flaws (cracks oriented favorably to the beam).

The most fundamental NDE method, involving direct or remote visual examination of equipment surfaces for signs of degradation, damage, leakage, misalignment, or other anomalies. Visual inspection detects surface conditions including corrosion, coating breakdown, distortion, discoloration, leakage staining, insulation damage, and mechanical damage. It may be performed directly, with magnification aids, or remotely using cameras, borescopes, or drones.

A damage mechanism involving the initiation and propagation of cracks in a material under the combined action of tensile stress (applied or residual) and a specific corrosive environment. SCC is insidious because it can occur in materials that are resistant to general corrosion, at stress levels below the yield strength, and with minimal visible surface degradation. Common forms include chloride SCC (austenitic SS), caustic SCC, amine SCC, polythionic acid SCC, and sulfide stress cracking.