MAGNETIC PARTICLE INSPECTION

Magnetic particle Inspection (MPI) is a non-destructive testing (NDT) process for detecting surface and shallow subsurface discontinuities in ferromagnetic materials such as iron, nickel, cobalt, and some of their alloys. The process puts a magnetic field into the part. The piece can be magnetized by direct or indirect magnetization. Direct magnetization occurs when the electric current is passed through the test object and a magnetic field is formed in the material. Indirect magnetization occurs when no electric current is passed through the test object, but a magnetic field is applied from an outside source. The magnetic lines of force are perpendicular to the direction of the electric current, which may be either alternating current (AC) or some form of direct current (DC) (rectified AC).

The presence of a surface or subsurface discontinuity in the material allows the magnetic flux to leak, since air cannot support as much magnetic field per unit volume as metals.

To identify a leak, ferrous particles, either dry or in a wet suspension, are applied to a part. These are attracted to an area of flux leakage and form what is known as an indication, which is evaluated to determine its nature, cause, and course of action, if any.

 

Application Specific Standards

  • EN 12952-6, Water-tube boilers and auxiliary installations Inspection during construction; documentation and marking of pressure parts of the boiler
  • EN 12953-5, Shell boilers. Inspection during construction, documentation and marking of pressure parts of the boiler
  • EN 13480-5, Metallic industrial piping Inspection and testing
  • EN 13445-5, Unfired pressure vessels Inspection and testing
  • EN 12732, Gas infrastructure. Welding steel pipework. Functional requirements
  • EN 14015, Specification for the design and manufacture of site built, vertical, cylindrical, flat-bottomed, above ground, welded, steel tanks for the storage of liquids at ambient temperature and above
  • EN 1090-2, Execution of steel structures and aluminium structures Technical requirements for steel structures
  • EN 14197-2, Cryogenic vessels. Static non-vacuum insulated vessels Design, fabrication, inspection and testing
  • EN 13458-2, Cryogenic vessels. Static vacuum insulated vessels Design, fabrication, inspection and testing
  • EN-ISO 9606-1, Qualification testing of welders. Fusion welding Steels
  • EN-ISO 9606-2, Qualification test of welders. Fusion welding Aluminium and aluminium alloys
  • EN ISO 15614-1 Specification and qualification of welding procedures for metallic materials. Welding procedure test. Arc and gas welding of steels and arc welding of nickel and nickel alloys
  • EN-ISO 17635, Non-destructive testing of welds. General rules for metallic materials

Standards Specific to Magnetic Particle Examination

  • EN-ISO 17638, Non-destructive testing of welds – Magnetic particle testing
  • EN-ISO 23278, Non-destructive testing of welds – Magnetic particle testing of welds – Acceptance levels
  • EN 10228-1, Non-destructive testing of steel forgings – Magnetic particle inspection
  • EN 1369, Founding. Magnetic particle testing
  • ISO 9934-1, Non-destructive testing – Magnetic particle testing – Part 1: General principles
  • ISO 9934-2, Non-destructive testing – Magnetic particle testing – Part 2: Detection media
  • ISO 9934-3, Non-destructive testing – Magnetic particle testing – Part 3: Equipment
  • ISO 3059, Non-destructive testing – Penetrant testing and magnetic particle testing – Viewing conditions
  • ASME Boiler and Pressure Vessel Code Section V Article 7 – Magnetic Particle Examination
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