b'FEATURED EXPERTFeatured ExpertBonnie PankratzNDT METHODS Ultrasonic testing is commonly used as there are The most important question you need to ask whensignificant advantages of UT over RT in terms of cost approaching inspection and testing, is what do youefficiency.UTcanbedoneduringregularshifts, want to accomplish? How does the inspection andandassoonasCodeallowancespermit. 2The testing that is done affect my bottom line, and whattechnician is able to work alongside fabrication and informationdoyouneedfortheapplication?Thismarkdeficiencieswhilefabricationisprogressing. article is intended only as a basic introduction to guideTwo significant things to note are that UT is only as and direct you to use the most efficient testing methodgoodasthetechnicianperformingthework.The for your project.competency of the technician is an important factor in this method; secondly, there is no permanent record of SURFACE METHODS the acceptable results. Visual Inspection, Magnetic Particle Testing and LiquidRadiographicTestingiscomprisedoftwo PenetrantTestingareconsideredsurfacetestingmethods: X-ray and Gamma Ray. X-ray is limited methods; these methods assess the weld metal oras to the thickness of the material that it can parent material at a surface level. Visual Inspection istest, so typically Gamma Ray is the method used not just for welds; it is an important part of the qualityin structural steel. Gamma Ray, though, provides overview for dimensioning and general workmanship.a permanent record and is less subject in terms Magnetic Particle Testing (MT) has three types of testof the competency of the technician, and the methods,whichrangeintermsofsensitivity.Howcost efficiency of the method is less attractive. critical the area is and the surface type will determineGamma Ray testing requires that the fabrication theappropriatemethod.Drypowder,blackonarea and often the building be clear of non-RT white (also called the wet method) and fluorescentpersonnel.RadiographicTestingisoften give increasing levels of sensitivity. It is important toperformed during night shifts, which requires a mention that MT can only be performed on materialcost premium to be paid, as well as preventing thatismagnetic,typicallycarbonsteel.Magneticthe option of a night shift for fabrication. Particle Testing is not suitable for aluminum or stainlessPhasedArrayUltrasound(PAUT)isbecoming steel applications.more widely accepted. This advanced NDT method combines that accessibility of UT with the ability SUBSURFACE METHODS to provide a permanent printed record. CSA W59 3Ultrasonic Testing (UT) and Radiographic Testing (RT)has been recently revised to allow for the use of arekeytestingmethodsinstructuralsteel.ThesePAUT in structural steel applications. This method methods are important tools in structural steel. CSAhas some of the concerns of conventional UT, in that 1. CSA S6 A10.1.8.2 S6 1will require weld splices to be ultrasonically orthe competency of the technician is integral to the 2. CSA S16 annex 193. CSA W59 7.4.3.1 radiographically tested.results. The qualifications and training are different 10|WINTER 2020 ADVANTAGE STEEL'