Eddy current testing compares the condition of a test object to that of a reference standard of sound material with known defects. When the test coil is placed next to an electrically conductive part, the primary magnetic field causes eddy currents to flow in the part. This flow of eddy currents induced in a material generates a second magnetic field in the part called a secondary field. Flaws create interruptions in the field – then the change in the current flow is represented on the instrument’s screen.
ECT, MFL, RFT, Tube and Surface Inspection, Material Sorting, Conductivity of Material.
This method detects discontinuities at or near the surface of ferromagnetic materials. The examination consists of magnetizing an article and applying magnetic particles to the surface of the article. Then the test surface is examined for any accumulation of particles at points causing magnetic field leakage, indicating discontinuities, and the indications are evaluated to an acceptance standard.
This technique detects surface and subsurface defects in a part or assembly. X-rays are produced when electrons traveling at a high speed in a vacuum are stopped by matter. Some of the radiation will be absorbed and scattered as it passes through the part. When the beam of penetrating radiation is directed through the part, the amount of radiation passing through the part is observed and recorded on X-ray film. In computed radiography, the image is recorded on an imaging plate. After the film or plate is processed, a shadow picture of the internal structure of the part is obtained. This technique is used to inspect castings, welds, wrought structures, adhesive bonds/composites, aircraft structure and instruments.
Gamma, X-Ray, Under Insulation Corrosion Testing, Digital
A series of electrical pulses is applied to a transducer, which converts the pulses to mechanical energy in the form of pulsed waves at a selected nominal frequency. The transducer transmits the waves into the material through the surface of the part and couplant. Pulsed energy is transmitted into the material and is reflected to the search unit by a discontinuity or boundary which is parallel or near parallel to the contacted surface. By comparison of the displayed signal amplitudes to those from a reference standard, both location and estimated discontinuity size may be determined.
A method used to detect discontinuities open to the surface. Penetrant is applied to the surface being examined, and allowed sufficient time to enter discontinuities by capillary action. The excess penetrant is then removed from the surface in such a manner as to leave the penetrant in the discontinuity cavities undisturbed. A developer is applied. The developer acts as an absorbent blotter to draw the penetrant out of the discontinuity cavity. The bleeding penetrant back to the surface into the developer causes an indication in the form of a penetrant stain in the developer coating. The amount and type of indication bleed-out is then interpreted and evaluated to the appropriate acceptance criteria.
This is the visual observation of the surface of a test object to evaluate the presence of surface discontinuities. VT inspections may be by Direct Viewing, using line-of sight vision, or may be enhanced with the use of optical instruments such as magnifying glasses, mirrors, boroscopes, charge-coupled devices (CCDs) and computer-assisted viewing systems (Remote Viewing). Corrosion, misalignment of parts, physical damage and cracks are just some of the discontinuities that may be detected by visual examinations.
Remote Visual Inspection (RVI)- AWS, ASME, API Direct, Remote, Borescope