TECHNICAL RESOURCE CENTER
Knowledge Base
For Modern NDT
Explore comprehensive guides on Non-Destructive Testing methodologies, standards, and advanced industrial inspections.
Magnetic Particle Testing (MT)
Magnetic Particle Testing (MT) is used to detect surface and subsurface in Ferro-electric/magnetic materials such as iron, nickel, cobalt, and some of their alloys. The process inducts a magnetic field into the part. The piece can be magnetized by direct or indirect magnetization. Direct magnetization occurs when an 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 travel 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 creates magnetic flux leakage. Ferrous iron particles are applied to the part. The particles may be dry or in a wet suspension. If an area of flux leakage is present the particles will be attracted to this area. The particles will build up at the area of leakage and form what is known as an indication. The indication is then evaluated to determine what it is, what may have caused it, and what action should be taken if any.
- Ferromagnetic materials
- Surface and slightly subsurface flaws
- Welds, tubing, bars, castings, billets, forgings
- Extrusions, engine components, shafts and gears
- Limited by field strength and direction
- Needs clean and relatively smooth surface
- Holding fixtures required for some techniques
- Test piece may need difficult demagnetization
- Depth of flaw not indicated
Radiography Testing (RT)
In Radiography Testing (RT) the test-part is placed between the radiation source and film (or detector). The material density and thickness differences of the test-part will attenuate (i.e. reduce) the penetrating radiation through interaction processes involving scattering and/or absorption. The differences in absorption are then recorded on film(s) or through an electronic means. In industrial radiography there are several imaging methods available, techniques to display the final image, i.e. Film Radiography, Real Time Radiography (RTR), Computed Tomography (CT), Digital Radiography (DR) and Computed Radiography (CR).
Film Based Radiography
Industrial radio-graphic methods are not unlike x-rays taken in a hospital. A piece of film is positioned beneath a suspected fracture, radiation directed through it exposes the film. The choice of radiation sources depends on material composition and size. The processed film provides a permanent inspection record.
Digital Radiography
Film is replaced by special phosphor screens or micro-electronic flat panel screens. Details can be easily increased and enhanced for expert interpretation. Digital Radiography files are easily shared and archived.
Computerized / Digital (CR)
Allows for onsite processing in remote locations using the latest system provided by VMI. CR is a great method for profile radiography, corrosion detection in piping/valves or looking for re-bar in concrete. Everything is stored digitally for easy retrieval.
Radiography Neutron
Apps: Metals, composites, pyrotechnics, resins, organic material.
Limits: Large reactor housing; Radiation hazards; Cracks must be parallel to beam.
Radiography X-Ray
Apps: All shapes: castings, welds, electronic assemblies, aerospace, marine.
Limits: Access to both sides; Voltage and focal spot size critical.
Radiography Gamma
Apps: Dense or thick material; Used where thickness limits X-ray generators.
Limits: Cracks must be parallel to beam; Not as sensitive as X-rays.
Ultrasonic Testing (UT)
UT is a portable volumetric examination that uses high frequency sound waves to exam, measure and inspect for thickness, flaws and weakness. Human and material flaws will never be completely eliminated and in-service damage and corrosion require continual “safe use” evaluation.
Assess corrosion, erosion, and mechanical damage of structural materials on tanks, vessels, piping, and structural steel. Data is used to assess life expectancy.
Battery operated, hand held system with full C-Scan display. Ideal for confined or awkward locations. Data can be transferred to computers for gridding large areas.
Effective test for weld inspection in pipes and pressure vessels where other methods are not feasible. Great for fusion type defects or cracks.
- Good penetrating power for deep faults
- High sensitivity for small flaws
- Access from only one surface
- Instruments are highly portable
- Requires experienced technicians
- Requires significant technical knowledge
- Scattering by material structure
Visual Testing (VT)
Visual Testing is the most common and usually first NDT examination step. The human eye has an amazing ability to differentiate between colors, hues, shapes, sizes contrast and texture. Inspections may require use of magnifying glasses, mirrors for a closer look or viewing material in limited access locations. Visual inspections are used to detect visible discontinuities and also to interpret visual data from other NDT processes.
Hardness Testing (HT)
Measure of weld and material hardness defined as resistance to indentation. Gauged by assessing the depth of an indent or incision made by a precisely shaped Indenter applied with an exact force over a specified time.
Positive Material Identification (PMI)
Vingrity technicians identify and verify ferrous and nonferrous alloys with portable XRF equipment. Equipment sends a low voltage radioactive signal into the material, returning element signals based on atomic structure. Results are immediate and non-destructive. Includes Ferrite Testing (FT) to assess corrosion susceptibility for austenitic and duplex materials.
Advanced Inspection Solutions
Phased Array (PAUT): An advanced alternative to radiography. Qualified to inspect tubes 48mm to 1,524mm and thicknesses 5mm+. Semi-automated for better speed and pin-point accuracy for repairs. Eliminates chemicals/film waste.
Safe method for locations not accessible by conventional means. Case Study: RAVI was used during a chemical plant start-up to avoid expensive disassembly of large pipes, ensuring no construction debris remained to destroy new pumping systems.
Remote Video (RVI) Systems:
Thermal Imaging & Coating
Thermal Imaging: Detect energy in infrared spectrum for insulation deficiencies and predictive maintenance.
Holiday Coating: Detects pinholes in protective coating using voltage “sparks”.
Vingrity is CWB Certified
Vingrity is also a CWB (Canadian Welding Bureau) Certified Inspection Organization as per CSA standard for the below product categories to conduct VT. MT and UT.