Magnetic Particle Testing (MT), also commonly referred to as Magnetic Particle Inspection (MPI), is a non-destructive testing method used to detect surface and near-surface discontinuities in ferromagnetic materials.
The method is particularly effective for detecting cracks and other linear discontinuities in welds, forgings, castings, and other components made from materials that can be magnetized.
Common Applications
Rivest Technologies provides Magnetic Particle Testing for applications including:
Weld and welded component inspection
Structural steel and fabrication welds
Pressure piping and pressure equipment
Forgings
Castings
Machinery and industrial components
In-service inspection for cracking and other discontinuities
How Magnetic Particle Testing Works
During a magnetic particle examination, a magnetic field is established in the area of the component being inspected.
If a surface or near-surface discontinuity interrupts the magnetic field, magnetic flux leakage occurs at the discontinuity. Fine magnetic particles applied to the surface are attracted to this leakage field and form a visible indication.
The technician evaluates these indications to determine their relevance and, where required, evaluates them in accordance with the applicable code, standard, procedure, or client specification.
Because the orientation of the magnetic field affects the ability to detect discontinuities, examination techniques are selected to provide appropriate sensitivity to discontinuities in the area being inspected.
Magnetic Particle Testing Techniques
Rivest Technologies provides several conventional Magnetic Particle Testing techniques to suit different inspection conditions and examination requirements.
Dry Visible Powder MT — Dry magnetic particles are applied to the examination surface while the appropriate magnetic field is established. This portable technique is well suited to many field applications and allows indications to be evaluated under suitable visible-light conditions.
Wet Fluorescent MT — Fluorescent magnetic particles suspended in a liquid carrier are applied to the examination area. Indications are evaluated using appropriate UV-A illumination under controlled lighting conditions. Fluorescent particles can provide increased visibility and sensitivity for detecting fine discontinuities.
Visible Colour-Contrast MT — Visible magnetic particles are used to create a contrasting indication against the examination surface. Where appropriate, a contrasting background coating may be used to improve indication visibility. This technique provides a practical method for field inspection under suitable visible-light conditions.
Advantages of Magnetic Particle Testing
Magnetic Particle Testing offers several advantages for industrial inspection:
Detection of surface and near-surface discontinuities
High sensitivity to cracks and other linear discontinuities
Immediate inspection results
Portable equipment suitable for field applications
Examination of welds, forgings, castings, and other ferromagnetic components
Relatively rapid examination of accessible areas
Indications are formed directly at the location of a discontinuity
Multiple techniques can be selected to suit inspection conditions
MT is especially useful where cracking or other surface and slightly subsurface discontinuities are of concern. The method is limited to materials capable of being magnetized and is therefore not suitable for non-ferromagnetic materials.
Rivest Technologies Magnetic Particle Testing Services
Rivest Technologies Inc. provides conventional Magnetic Particle Testing (MT) for industrial, fabrication, construction, and in-service inspection applications.
Our magnetic particle examinations are performed by CGSB Level II certified MT technicians using established procedures and the applicable code, standard, or client specification.
Our MT capabilities include:
Dry Visible Powder Testing — Portable magnetic particle examination suitable for many weld, fabrication, and field inspection applications.
Wet Fluorescent Testing — Fluorescent magnetic particle examination for applications requiring enhanced visibility and sensitivity to fine surface and near-surface discontinuities.
Visible Colour-Contrast Testing — Visible magnetic particle examination using contrasting particles and, where appropriate, a contrasting background to improve indication visibility.
Weld Inspection — Examination of ferromagnetic welded joints for surface and near-surface discontinuities in accordance with applicable acceptance criteria.
Forging and Casting Inspection — Magnetic particle examination of suitable ferromagnetic forgings and castings for relevant surface and near-surface discontinuities.
Rivest Technologies provides both shop and field Magnetic Particle Testing with an emphasis on reliable examination, clear documentation, and responsive service.
Codes, Standards and Inspection Requirements
Magnetic Particle Testing requirements vary according to the component, material, industry, governing construction code, and client specification.
Depending on the application, examinations may be performed in accordance with applicable CSA, ASME, ASTM, or other industry codes, standards, procedures, and client specifications.
ASTM E709 provides guidance for dry and wet magnetic particle testing and its application to welds, castings, forgings, finished materials, and other ferromagnetic components. The applicable construction code or specification establishes the specific examination and acceptance requirements for the component being inspected.
Inspection technique, surface preparation, magnetization, lighting conditions, examination coverage, evaluation, and acceptance criteria are determined by the requirements applicable to the specific inspection.
Qualified Inspection Personnel
Rivest Technologies' Magnetic Particle Testing examinations are performed by CGSB Level II certified MT technicians.
CGSB certification provides an established framework for the qualification and certification of non-destructive testing personnel, including requirements relating to training, experience, and examination.
Our technicians combine this qualification with practical field experience to identify and evaluate relevant magnetic particle indications in accordance with applicable inspection requirements.
Need Magnetic Particle Testing Services?
For information about Magnetic Particle Testing, inspection requirements, scheduling, or pricing, contact Rivest Technologies Inc.
Click for a VIDEO demonstration.
See the Wikipedia page for more information.