Magnetic Particle Inspection (MPI / MT)
Engineering definition, metallurgical mechanisms, standard testing specifications, and manufacturing guidelines for closed-die forgings up to 50 kg.
Quick AnswerFeatured
A non-destructive testing method that magnetizes ferromagnetic parts to detect surface and shallow sub-surface defects through magnetic flux leakage.
Technical Explanation & Metallurgical Principles
In MPI, a magnetic field is induced across a ferromagnetic forging (using an AC/DC electromagnetic yoke or prods). When the magnetic lines of force encounter a crack or non-metallic seam, flux leaks out into the surrounding air. Finely divided iron particles coated with fluorescent or black dye are attracted to this leakage, creating vivid visual indications.
Key Engineering Specifications & Parameters
| Technical Parameter / Metric | Engineering Benchmark / Value |
|---|---|
| Technique | Fluorescent wet continuous method under UV light (ASTM E1444) |
| Defect Depth | Surface and near-surface (up to ~2mm deep) |
Application at Jayesh Forge (Rajkot Plant)
100% wet fluorescent magnetic particle inspection performed on carbon and alloy steel flanges, gear blanks, and couplings at our Rajkot NDT cell.
Related Materials, Standards & Products
Applicable Material Grades
Engineered Product Lines
Related Metallurgical & Testing Terms
Liquid Penetrant Inspection (Dye Penetrant / PT)
A non-destructive testing method that applies a visible or fluorescent liquid dye into surface-breaking cracks, drawing it out with a chalk developer to reveal flaws.
Ultrasonic Testing (UT / Pulse-Echo Examination)
A volumetric non-destructive examination technique using high-frequency sound waves (1 to 5 MHz) to detect internal flaws, voids, and non-metallic inclusions in thick forgings.
Questions Regarding Magnetic Particle Inspection (MPI / MT)
No, MPI strictly requires ferromagnetic materials; stainless 304/316 must be inspected using dye penetrant testing (PT).
Request a Forging Quote with Magnetic Particle Inspection (MPI / MT) Compliance
Our Rajkot metallurgy desk is ready to review your technical drawings, testing protocols, and delivery schedules for custom closed-die forgings strictly up to 50 kg.