{"id":6276,"count":10,"description":"Flaw inspection and control includes methods and instruments used to identify surface discontinuities, near-surface indications or interruptions in protective coatings. The choice of the most suitable technique depends on the material to be inspected, the type of anomaly being sought and whether an insulating coating is present on the component.\r\n\r\nA discontinuity does not automatically constitute an unacceptable flaw: the detected indication must be assessed according to the component, the process carried out, the intended use and the applicable acceptance criteria. Cracks, porosity, weld defects, inclusions, pinholes and interruptions in coatings require different inspection methods because each technique is designed for a specific application field.\r\n\r\nThis category includes instruments and consumables for penetrant testing (PT), magnetic particle testing (MT) and continuity checks on insulating coatings using holiday detectors. These solutions are used in quality control, production inspections, maintenance activities and the acceptance of components and structures.\r\n<h2>Penetrant testing (PT)<\/h2>\r\nPenetrant testing (PT) is used to identify surface-breaking discontinuities on non-porous materials compatible with the method. It is suitable for inspecting welds, castings, machined parts, fittings and components made from non-ferromagnetic materials.\r\n\r\nThe method is based on applying a red penetrant liquid to a previously cleaned surface. The penetrant enters surface-breaking discontinuities and, after excess penetrant has been removed, is drawn back to the surface by a white developer, making indications visible through colour contrast.\r\n\r\nThe inspection cycle therefore includes complementary products: solvent &amp; cleaner spray for surface preparation and cleaning, red penetrant spray for entering discontinuities and white developer for making indications visible. The availability of developers with different characteristics makes it possible to select the most suitable solution according to the application and the contrast required.\r\n\r\nPenetrant testing is referenced in UNI EN ISO 3452-1, which covers the general principles of the PT method.\r\n<h2>Magnetic particle testing (MT)<\/h2>\r\nMagnetic particle testing (MT) is intended for components made from ferromagnetic materials and makes it possible to reveal surface and near-surface indications. During the inspection, the part is magnetised and, at a discontinuity, the magnetic flux produces local leakage that attracts the magnetic particles applied to the area being inspected.\r\n\r\nThe AC\/DC magnetic particle yoke, also called a magnetic yoke or electromagnetic yoke, allows local magnetisation of welds, castings, forgings, pipes, fabricated structures and mechanical components. Used together with black magnetic particle spray, it makes the indications generated during the inspection visible.\r\n\r\nWhen the component surface is dark or provides little contrast, white contrast paint creates a light background on which black indications are easier to read. Solvent &amp; cleaner spray can then be used to remove the white contrast paint at the end of the inspection, completing the visible magnetic particle testing cycle.\r\n\r\nThe range also includes instruments complementary to the MT method. The ASME octagonal field indicator is used to verify the orientation of the magnetic field applied during the inspection, while the digital gaussmeter measures the magnetic field present on the component and makes it possible to check for residual magnetisation after the examination or after a demagnetisation stage.\r\n\r\nFor magnetic particle testing, detection media and equipment are linked to UNI EN ISO 9934-2 and UNI EN ISO 9934-3. ASTM E709 and ASME BPVC Section V, Article 7 also apply to specific inspection procedures.\r\n<h2>Holiday detectors for insulating coatings<\/h2>\r\nHoliday detectors are used to verify the continuity of insulating coatings applied to conductive substrates. They make it possible to identify porosity, pinholes or uncovered areas that may compromise the protection of the underlying substrate.\r\n\r\nThese instruments are used to inspect coated pipes, tanks, vessels, metal structures and surfaces protected by paints or insulating coatings. A particularly important application concerns pipes installed and welded on site: after restoring the coating in the joint area, the holiday detector makes it possible to verify that the applied covering has no discontinuities before final installation or commissioning.\r\n\r\nHigh-voltage holiday detectors are suitable for thicker coatings and extensive inspections. According to the geometry of the component, they can be used with flat probes, fan probes, circular spring probes for 360\u00b0 external inspection of pipes or arc brushes for internal pipe inspection.\r\n\r\nFor thin insulating coatings, a wet sponge holiday detector is available for coatings up to 500 \u00b5m. The moistened sponge is moved across the coated surface while the wet sponge holiday detector is available for coatings up to 500 \u00b5m. The moistened sponge is moved across the coated surface while the earth lead is connected to the conductive substrate. In the presence of a through-coating discontinuity, the liquid reaches the underlying substrate, the electrical circuit closes and the instrument identifies the affected area through visual and audible alarms.\r\n\r\nFor non-conductive protective coatings applied to metallic substrates, holiday detector inspection is referenced in ASTM D5162, with Method A for wet sponge testing and Method B for high-voltage testing. For coatings applied to pipes, ASTM G62 is the reference, respectively Method A for wet sponge testing and Method B for high-voltage inspection. ISO 29601 covers porosity testing in dry films of protective paint systems applied to metallic substrates.\r\n<h2>How to choose the inspection method<\/h2>\r\nPenetrant testing (PT) is suitable when surface-breaking discontinuities must be identified on non-porous materials, including non-ferromagnetic materials compatible with the method. Magnetic particle testing (MT), on the other hand, is the appropriate solution for ferromagnetic components when surface or near-surface indications are sought through magnetisation and magnetic particles.\r\n\r\nHoliday detectors address a different requirement: they are not used to look for flaws in the component material, but to verify the continuity of an insulating coating applied to a conductive substrate. The choice between a high-voltage holiday detector and a wet sponge model depends mainly on coating thickness and the required inspection procedure.\r\n\r\nThe range therefore makes it possible to select the method most consistent with the actual application: inspection of surface discontinuities by penetrant testing, magnetic particle testing of ferromagnetic components or detection of porosity and pinholes in protective coatings using holiday detectors.","link":"https:\/\/www.samatools.it\/en\/ndt-control-instruments\/flaw-inspections\/","name":"Flaw inspection and control","slug":"flaw-inspections","taxonomy":"product_cat","parent":6240,"meta":[],"menu_order":4,"acf":[],"permalink_manager":null,"_links":{"self":[{"href":"https:\/\/www.samatools.it\/en\/wp-json\/wp\/v2\/product_cat\/6276","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.samatools.it\/en\/wp-json\/wp\/v2\/product_cat"}],"about":[{"href":"https:\/\/www.samatools.it\/en\/wp-json\/wp\/v2\/taxonomies\/product_cat"}],"up":[{"embeddable":true,"href":"https:\/\/www.samatools.it\/en\/wp-json\/wp\/v2\/product_cat\/6240"}],"wp:post_type":[{"href":"https:\/\/www.samatools.it\/en\/wp-json\/wp\/v2\/product?product_cat=6276"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}