NDT testing means without prejudice or affect the detected object performance, not hurt at being provided to detect objects within the organization, the use of material internal structural abnormalities or defects heat, sound, light, electricity, magnetism and other reactions caused by changes to physical or chemical methods as a means of using modern technology and equipment, equipment, the specimen surface and the interior of the structure, properties, and defect type state, nature, number, shape, position, size, distribution and change inspection and test methods . Non-destructive testing is an effective tool of industrial development is essential, to a certain extent reflects the level of industrial development of a country, the importance of non-destructive testing has been recognized, the main ray inspection (RT), ultrasonic testing (UT), magnetic particle testing (MT) and liquid penetrant testing (PT) four. There are other NDT methods eddy current testing (ECT), acoustic emission testing (AE), thermal imaging / infrared (TIR), leak testing (LT), the AC field measurement techniques (ACFMT), magnetic flux leakage testing (MFL), far-field test detection (RFT), ultrasonic time of flight diffraction method (TOFD) and the like.
NDT testing is the use of sound material, optical, magnetic and electrical characteristics such as, without prejudice or affect the performance of the detection object premise of the existence of defects or unevenness in the detection of the test object, given defect size, location the nature and quantity of information. Compared with the destructive testing, nondestructive testing has the following characteristics. The first is a non-destructive, because when it is done without compromising detection performance by using a detection object; a second comprehensive, since the detection is non-destructive, so the object can be detected 100% comprehensive testing, if necessary this is destructive detection impossible; the third has a full, destructive detection generally apply only to the raw materials testing, such as mechanical engineering commonly used in tension, compression, bending, etc., are for nondestructive testing manufacturing of raw materials, finished products and for the supplies, unless the service is not ready to let it continue, otherwise it is not destructive detection and non-destructive testing without damaging the object to be detected by the use of performance. Therefore, it is not only the raw materials used to manufacture each intermediate step of the process of welded steel pipe, until the final finished products for the entire testing, but also on the service in the device for testing.
NDT Visual inspection: 1, the weld surface defect inspection. Check the weld surface cracks, incomplete penetration and weld leak welding quality. 2, the state examination. Check the surface cracks, peeling, cable, scratches, dents, bumps, spots, corrosion and other defects. 3, cavity inspection. When certain products (such as worm gear pumps, engines, etc.) work, according to the technical requirements of the project will be remote visual inspection. 4, assembly inspection. When required, and when needed, using the same three-dimensional industrial video endoscope assembly quality inspection; or a step after assembly is complete, check the parts and components assembled position meets the conditions for drawing or technical requirements; the existence of assembly defects. 5, extra material inspection. Check the product within the lumen of the residual dust, foreign objects and other remnants.