Thermography Method for Detection of Welded Defects in Steel Structures

Abstract The fourth industrial revolution has driven technological advancements in construction, particularly in safety inspection and the development of taller structures. Traditional structural inspections, relying on contact‐based methods, are costly, time‐consuming, and pose safety risks for inspectors, with issues of data subjectivity. As a result, there is a need for more efficient, non‐contact defect detection techniques. Infrared thermography has emerged as a promising non‐destructive testing method, widely used in detecting defects in concrete structures; however, its application in to identify welding defects in steel structures remains underexplored. This study aims to detect welded defects in steel structures swiftly and accurately using infrared thermography. Test specimens with artificial defects were fabricated and evaluated using the passive infrared method. Thermal images and surface temperature data of defective and normal welds were analyzed, with defect presence determined based on the standard deviation of weld temperature. The passive method, conducted outdoors, revealed significant differences in standard deviation between defective and normal parts, demonstrating the potential of infrared thermography for effectively detecting welding defects in steel structures.