Non-destructive testing also referred to as NDT, is a method of assessing the properties of a material, component, or even a system. It is a varied set of evaluation techniques used in the science and technology industry. It causes no damage to the material or component being tested. It is both highly economical and efficient. NDT is useful in research, troubleshooting and mainly, evaluation, as it never harms the product it anyway. The fields that use NDT are aeronautical engineering, forensic engineering, mechanical engineering, medicine, civil engineering, petroleum engineering, etc.
Visual testing, Ultrasonic, Eddy- Current, Magnetic-Particle, Radiographic and Liquid-penetrant.
Visual Testing is the most commonly used non-destructive testing methods method. It uses cameras, borescopes, magnification tools and several other optical tools and settings. The internal structure can be put to test using X-rays, neutrons and also gamma radiation.
NDT is applicable throughout various industries and industrial activity. It is a very versatile evaluation method. Every day, new ways to carry out Non-Destructive Testing are being developed worldwide. All the new developments add to its usefulness. It is mainly put to use when the failure of a material/component poses hazards or causes damage. Such events may occur during transportation or in piping, pressure vessels, etc. Non Destructive Testing is further divided into methods of non-destructive testing. All the methods are based on certain scientific principles. Those methods can be divided even more to techniques. Each method and technique, owing to their unique features have specific applications. It can be used in different and exclusive situations depending on what is required. Choosing the most optimal method or technique according to the need is imperative. Thorough knowledge of all methods and techniques are necessary for making an informed choice.
Non Destructive testing is a tried and tested method that has been in practice for many years. It is a cost-efficient method of testing. Safety is ensured throughout the process and it is also extremely reliable in producing the best results. It makes sure that there is no disturbance to any of the activities carried out by the firm, the workers, or even the machinery.
Non Destructive testing helps to discover any safety concerns that the product may pose. This method of testing also offers reassurance regarding the quality of the concerned product. Additionally, undertaking NDT can further improve the profitability and output of your firm. Most, if not all, flaws of the product under scrutiny will be revealed through Non-destructive testing. This can help you find out where you need to introduce improvements and changes. This testing method continues to provide accurate results. The most notable feature of it is that it is efficient and causes absolutely no harm to the product being examined. Due to this factor, all industries use this method for the evaluation of new components and systems.
Conducting a rebound hammer test as per IS 13311(Part-2), ASTM C 805. The rebound hammer test shall be conducted at all those points were the UPV test has been performed. One point consisting of six readings spread over an area of 1 sq. shall be considered as 1 test.
Conducting Ultra-Sonic Pulse velocity (UPV) test at selected locations on the RCC members of the Structures covered under the study by making 300 mm x300mm c/c grids to know about the homogeneity and quality of concrete. The test is performed as per the IS 13311 (Part-1) / ASTM C 597.
Extracting the concrete core samples of minimum 65 mm diameter and 100-150 mm length (approx.) from a selected location forms RCC members of the structures covered under the study and evaluation of the properties in the laboratory from the core sample selected. IS 456:2000; IS 516:1959; IS 1199:2002; ASTM C-42.
As per ASTM C-900
Measuring the half-cell /surface potential at the selected location on RCC members of the structures covered under the study will help in understanding the extent of reinforcement corrosion as per ASTM C 876.
At a selected location on the RCC members of the structures covered under the study see the adequacy of concrete cover to rebars and effect of carbonation.
Measurement of carbonation depth by phenolphthalein spray test at the selected location on RCC members of the structures covered under the study is used to see the depth of carbonation.
Moisture profile of concrete with respect to depth.
Chemical analysis of chlorides, Sulfates, pH, alkali-silica, etc on concrete powder collected from the structures, covered under the study, by drilling to understand the chemical deterioration/degradation of concrete and its effect on reinforcement corrosion.
Here are the eight most-used NDT techniques:
Visual Testing (VT) …
Ultrasonic Testing (UT) …
Radiography Testing (RT) …
Eddy Current (Electromagnetic) Testing (ET) …
Magnetic Particle Testing (MT) …
Acoustic Emission Testing (AE) …
Liquid Penetrant Testing (PT) …
Leak Testing (LT)
NDT Technicians, also known as non-destructive testing technicians, perform tests and provide information about the condition of components and materials without destroying them.
Destructive testing destroys or alters the part so that even if it passes the test, it is no longer fit for service, whereas Non-destructive testing doesn’t eliminate or adjusts the part is still fit for use if it clears all the test.
Ultrasonic Testing (UT),
Radiographic Testing (RT),
Electromagnetic Testing (ET),
Magnetic Particle Testing (MT),
Liquid Penetrant Testing (PT),
Visual Testing (VT), are the six most frequently used non-destructive test.
Potential inspectors require a high school diploma or GED certification at the lever where the job will place them, and a background in engineering or related procedures will get into non-destructive testing.
Though NDT testing does not possess hazardous to testing personnel, however, it does involve potentially harmful exposures to ultraviolet radiation, ionizing radiation, or X-rays.