Thermography for Online Detection of Incomplete Penetration and Penetration Depth Estimation

Conventionally, the quality of the weld is ascertained only after the welding has been completed through the use of NDT techniques. A lot of time, material and manpower is wasted before one comes to know about the soundness of the weld. These limitations can be overcome if the weld is continuously monitored in real time for the assessment of defects using appropriate NDE sensors. This paper highlights the application of thermal imaging sensors for detection of defects such as lack of penetration and estimation of depth of penetration during Tungsten Inert Gas (TIG) welding. Analysis of the results confirms that IR technique can detect lack of penetration and depth of penetration online. A linear relationship could be established between the surface thermal profile and the depth of penetration.

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