Non Destructive Testing (NDT) of Welds
United can provide you with qualified technicians to perform non-destructive testing of welds. Our technicians are Level II qualified in accordance with the American Society for Nondestructive Testing (ASNT) Recommended Practice No. SNT-TC-1A, under the direct supervision of our corporate ASNT NDT Level III.
Ultrasonic Testing (UT)
In ultrasonic testing (UT), very short ultrasonic pulse-waves are launched into materials to detect internal flaws in welds or to characterize materials. The technique is also commonly used to determine the thickness of the test object, for example, to monitor pipework corrosion. It is also used to check for delamination of steel members. Any indications of defects are then compared with the appropriate acceptance criteria in the approved construction documents.
Magnetic Particle Testing (MT)
Magnetic particle inspection (MT) is a non-destructive testing (NDT) process for detecting surface and subsurface discontinuities in ferrous materials. The process puts a magnetic field into the part. The presence of a surface or subsurface discontinuity in the material allows the magnetic flux to leak. Ferrous iron particles are applied to the part. If an area of flux leakage is present the particles will be attracted to this area. The particles will build up at the area of leakage and form what is known as an indication. The indication can then be evaluated to determine what it is, what may have caused it, and what action should be taken if any.
Liquid Penetrant Testing (PT)
Liquid penetrant inspection (PT) is a widely utilized inspection method used to locate surface defects in welds. PT can also be used to detect casting and forging defects, cracks, and leaks in new products, and fatigue cracks on in-service components. A dye is applied to the material to be tested. The excess dye is then wiped from the surface. Any surface defects in the steel/weld would then be visible due to capillary action of the dye collecting in the crack/defect. The indication can then be evaluated to determine what it is, what may have caused it, and what action should be taken if any.