Magnetic Particle Inspection

Magnetic particle inspection (MPI) is a non-destructive testing method that detects surface or near-surface defects in ferromagnetic materials by observing the accumulation of magnetic particles in the leakage magnetic field near the defects. It can identify surface and near-surface defects in ferromagnetic products, which is divided into fluorescent magnetic particle inspection and non-fluorescent magnetic particle inspection. Typically, it can be used for laboratory sample inspections as well as on-site inspections.

Testing scope encompasses all stages of raw materials, production process, in-service period, and failure analysis throughout the entire life cycle of the product.

Application Scope

(1) Suitable for detecting ferromagnetic steel, but not for Austenitic stainless steel materials or welds welded with Austenitic stainless steel rods. Martensitic stainless steel can be magnetically particle inspected. Some precipitation-hardening stainless steels have low magnetic properties before heat treatment and are not suitable for magnetic particle inspection. Materials like copper, aluminum, magnesium, and titanium alloys are non-magnetic and cannot be used for magnetic particle inspection.

(2) Suitable for detecting surface and near-surface cracks, folds,疏松, cold shuts, seams, non-metallic inclusions, incomplete fusion, blowholes, and other defects. Not suitable for detecting shallow and wide scratches, deeply embedded internal defects, or defects at angles less than 45° to the magnetic lines.

(3) Suitable for inspecting raw materials (bars, tubes, sheets, profiles), forgings, castings, welded parts, and machined parts.

(4) Suitable for semi-finished and finished product inspections during the production process, as well as in-service, scheduled, and maintenance inspections.

Inspection Content

Magnetic particle inspection is used to detect surface and near-surface defects in ferromagnetic products by吸附magnetic particles onto discontinuities in the magnetic field. The Anmp Non-Destructive Testing Laboratory can specifically provide the following services:

1. Provides magnetic particle inspection services for industries such as aerospace, mechanical manufacturing, special equipment, construction materials, steel structures, infrastructure, nuclear power, bridges, railways, ships, chemicals, petrochemicals, and heavy industry; 2. Capable of detecting surface and near-surface defects in ferromagnetic products, particularly unopened near-surface defects; 3. Pressure pipelines: industrial pressure pipelines, oil and gas long-distance pipelines, industrial metal thermal pipelines, and industrial metal gas pipelines.

4. Pressure Vessels (including Gas Bottles): Power Industry Boilers, Fixed Pressure Vessels, Mobile Pressure Vessels

5. Structural Steel Projects: Building structural steel, road and bridge structural steel, hydraulic engineering structural steel, electrical engineering structural steel.

6. Boilers: Steam Boilers, Hot Water Boilers, Organic Heat Carrier Boilers

7. Lifting Equipment: Bridge Cranes, Gantry Cranes, Tower Cranes, Mobile Cranes, Railway Cranes, Portal Cranes, Mast Cranes, Jib Cranes, Cable Cranes, Light and Small Cranes

8. Passenger cableways, large-scale amusement facilities

9. Marine and Ship Products: Propulsion Systems, Cabin Equipment, Deck Machinery

10. Above-water steel structures for marine facilities

11. Castings, steel forgings, bolts, screws, studs, and nuts.

Billboard Inspections: Wall billboards, freestanding billboards, rooftop billboards.

Inspection Procedures

Pre-treatmentMagnetic workpieces → Apply magnetic powder or suspension → Observe and record → Explain and evaluate magnetic marks → Demagnetize → Post-processing.

The three operations of magnetic particle inspection are: the sample must be properly magnetized, suitable magnetic powder must be applied, and any magnetic indications must be reasonably explained and evaluated.Basic Elements.