Non-destructive examination includes a variety of inspection methods. For many types of welds, integrity is verified by visual inspection. In fact, visual inspection is the NDE method used for over 95 percent of welds made each day. Some of the reasons for the popularity of visual inspection are: ease in application; quick and relatively inexpensive; and historically has required no special equipment. Tools of the trade have included a flashlight, magnifying glass, scales and special gauges. Visual inspection involves more than just looking at the finished weld and declaring whether it is good or bad. The process begins before welding, by looking at the joint preparation, alignment and clearances. During welding, look at the requirements of the Welding Procedure Specification and make sure all requirements are being met. Root pass quality and joint fill are two characteristics that need to be verified. After welding, the completed weld must be measured and compared to the applicable quality standard. Type, location and size of any defects must be noted. Finally, visual inspection is required to verify that any weld defects are repaired properly.
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