Gamma-Tech Inspection Ltd.

MPT Fluorescent Fluorescent Magnetic Particles (requires a black light) are used in the detection of SURFACE and SUBSURFACE indications in FERROUS materials. Each product can be used for either WET or DRY methods of magnetic particle inspections. Particle size is controlled to ensure maximum sensitivity. Meets major specifications. Provides accurate, reliable crack detection results in the following applications:

• Automotive Components
• Manufacturers
• Welds
• Lifting Devices
• Test Labs
• Fabrication Shops
• Ski Lift Maintenance
• Steel Mills
• Pipelines
• Railroads
• Plant Maintenance

MPT Visual
Visible (daylight) Magnetic Particles are used for magnetic particle inspection method in the detection of SURFACE and SUBSURFACE indications in FERROUS materials. Each product can be used for either WET or DRY methods of magnetic particle inspections. Particle size is controlled to ensure maximum sensitivity. Meets major specifications. Provides accurate, reliable crack detection results in the following applications:

• Automotive Components
• Manufacturers
• Rebuilders
• Welds
• Lifting Devices
• Pipelines
• Railroads
• Test Labs
• Military
• Amusement Ride Maintenance
• Fabrication Shops
• Ski Lift Maintenance
• Steel Mills
• Plant Maintenance

Industrial radiography is used for a variety of applications but is commonly performed using two different sources of radiation, X-ray and Gamma ray sources.

The choice of radiation sources and their strength depends on a variety of factors including the size of the component and the material thickness. Within the broad group of X-ray and Gamma ray sources are a variety of exposure device choices with varying radiation strengths. Gamma-Tech radiographic capabilities use portable gamma-ray exposure devices for field weld applications up to 7″ tk. wall material inspection. Gamma sources vary from very low-level Iridium (IR192 – up to 3″ tk. steel) sources used for a variety of weld inspections, to Cobalt (Co 60 – up to 7″ tk. steel) inspections for thick component testing.

There are many advantages to radiography including inspection of a wide variety of material types with varying density, the ability to inspect assembled components, minimum surface preparation required, sensitivity to changes in thickness corrosion, voids, cracks and material density changes, the ability to detect both surface and subsurface defects and the ability to provide a permanent record of the inspection.

Traditional Ultrasonic inspection uses high-frequency sound energy to conduct examinations and perform measurements. Considerable information may be gathered during ultrasonic testing such as the presence of discontinuities, material or coating thickness. The detection and location of discontinuities are enabled by the interpretation of ultrasonic wave reflections generated by a transducer. These waves are introduced into a material and travel in a straight line and at a constant speed until they encounter a surface. The surface interface causes some of the wave energy to be reflected and the rest of it to be transmitted. The amount of reflected vs. transmitted energy is detected and provides information on the size of the reflector, and therefore the discontinuity encountered.

Three basic ultrasonic techniques are commonly used:

Normal/Angle Beam – Normal beam testing uses a sound beam that is introduced at 90 degrees to the surface – for thickness testing, while angle beam utilizes a beam that is introduced into the specimen at some angle other than 90 degrees – for defect location. The choice between the two is made based on the orientation of the feature of interest so that the sound may produce the largest reflection from the feature and obstructions on the surface of the specimen that must be avoided.

Some of the most common Ultrasonic applications are:

Flaw detection (cracks, inclusions, porosity, delaminating etc.)
Erosion/Corrosion thickness gauging Info from ultrasonic inspection can be presented in a number of formats: A-Scan displays the amount of received ultrasonic energy as a function of time Be-Scan displays a profile view (cross-sectional) of a specimen
C-Scan displays a plan type view of the specimen and discontinuities Hybrid/Stitched displays a C-Scan plan view with A and/or B Scan views along with C-Scan views that have been woven together to illustrate a clearer picture of the damaged areas of a specimen. The stitched views are used for larger specimens and surface areas.

Some of the major advantages of ultrasonic testing are:

Detects surface and subsurface defects Depth of penetration vs. other test methods are superior Only single-sided access is required with a pulse-echo technique High accuracy regarding estimating discontinuity size and shape Minimal specimen preparation is required Instantaneous results produced by using electronic equipment Detailed images can be produced with automated systems.

Major limitations of ultrasonic testing are:

The surface must be accessible. Skill training is more extensive than with some other methods for personnel. Normally requires couplant to promote sound transfer. Surface roughness, complex geometries, small parts or exceptionally thin materials are difficult to inspect. Coarse-grained material ie. Cast iron is difficult to inspect due to low sound transmission and high signal noise. Linear defects oriented parallel to the sound beam go undetected. Reference standards are required for equipment calibration for each item tested.

The most frequently requested form of liquid penetrating inspection we are asked to perform is visible, water removable, and non-aqueous (red/white). This method is very reliable and not detrimental to the parts being tested.

Penetrant testing is based on the properties of capillary action, or the phenomenon of a liquid rising or climbing when confined to a small opening due to surface wetting properties of the liquid. Penetrant testing is used for finding surface-breaking discontinuities on relatively smooth, nonporous surfaces.

The types of defects that can be found with Penetrant inspection are:

Rolled Products: Penetrant identifies anomalies (cracks, seams or laminations)

Castings: cold shuts, hot tears, porosity, blow holes or shrinkage

Forgings: Illuminating cracks, laps or external bursts

Welds: To identify cracks, porosity, undercut, overlap, and lack of fusion or lack of penetration.

There are two main types of Penetrants, Fluorescent and Visible. Within each method, there are several methods including water washable, post emulsifiable-lipophilic, solvent removal and post emulsifiable-hypertrophic. The type and penetrant method are chosen based on sensitivity levels 1-4 and on job site conditions and other variables.

Ferrite content analysis provides critical data about delta ferrite content in austenitic stainless steel and duplex materials. The delta ferrite percentage or number allows a technical assessment of material corrosion susceptibility, mechanical properties, service suitability, and reliability.

Ferrite testing is performed on austenitic stainless steel and duplex items, including (but not limited to) weldments, castings, weld overlays, wrought materials, and forgings. Ferrite content analysis can be obtained on butt/fillet welds, Category A-D welds, and stainless weld overlays on non-ferrous interfaces, cast components, and pre-and post-weld heat-treated components.

Ferrite testing, utilizing portable digital technology with variable calibration in both Ferrite Number (FN) and % Ferrite (FN) using AWS standards, allows for rapid and accurate analysis. Both in-service and in-construction components are tested.

To perform proper ferrite testing, both a minimum material thickness and a minimum specimen size are required. The shape of the specimen may hurt the results obtained, although correction calculations can be performed in some instances.

Surface preparation is very important to ensure result accuracy. Ferrite testing is not recommended where the material is at temperatures greater than approximately 125 F. Test results are interpreted by current specifications and/or customer requirements. Reports issued are accompanied when necessary by drawings to identify locations tested.