Non-destructive testing (NDT), also known as non-destructive examination (NDE), is an extremely useful tool for completing inspections without damaging the equipment being inspected. The purpose of these tests is to detect the location, size, shape, and development trend of internal or external defects.
Depending on the variety of equipment, a variety of different NDT methods can prove useful.
Ultrasonic testing is one of the most popular methods for testing steel pipe. In this method of testing, ultra-high frequency sound is introduced into the part being inspected. If the sound hits any flaws or discontinuities, some of the sound will be reflected at a unique rate. By knowing the speed of the sound through the part and the time required for the sound to return to the sending unit, the flaw or discontinuity can be located.
Radiography, both film and computerized digital, is another popular testing method. Radiographic tests are performed by placing a test object between a source of penetrating radiation and a recording medium such as silver bromide film.
Magnetic Particle Testing is another method of testing, this method is performed by using one or more magnetic fields to locate discontinuities in the surface or near-surface of ferromagnetic materials. The magnetic fields used for testing can be applied by either permanent magnets or electromagnets, and are usually used in conjunction with very fine colored ferromagnetic particles, which are visibly drawn into discontinuities by the magnetic forces acting upon them.
Liquid Penetrant Testing, another popular method of testing, involves the application of a very low viscosity liquid to the surface of the part being tested. Due to the low viscosity of the fluid, it easily penetrates flaws and discontinuities in the pipe, and when the excess penetrant is removed and the penetrant trapped in the imperfections flows back out, and indication has been created that marks the location of the flaw or discontinuity.
Visual testing is frequently used as a method of evaluating imperfections. This method of testing can be performed using unenhanced vision, but also may be performed with the aid of optical instruments such as magnifying glasses, mirrors, boroscopes, charge-coupled devices, and/or computer-assisted viewing systems. Many forms of damage to steel pipes can be detected via visual testing inspections. This form of testing is also used in conjunction with most other forms of testing, as a visual evaluation occurs as a side effect of performing other tests.
If you need non-destructive testing services for equipment, Encorus can provide the solutions you need. Contact our Director of NDE, Jim Handzlik, at 716.592.3980 ext. 148 or jhandzlik@encorus.com.
