Numerical Analysis of Influencing Factors and Capability for Line Laser Scanning Thermography Nondestructive Testing Technology in Chemicals Corrosion Defect Detection

A new Infrared Thermal Wave Nondestructive Testing (IR TWNDT) technology—line laser scanning thermography nondestructive testing (LLST NDT) technology is applied to detect the defect that caused by chemicals corrosion. The heat conduction process is derived and simulated by the numerical method. Parameters of LLST NDT as the maximum surface temperature difference (ΔT max), the best detection time (t best), and the temperature difference holding time (τ ΔT≥0.1) are discussed as the targets. Based on these parameters, factors influencing the detection results of materials, defect characters (size and depth), and thermal excitation source parameters (line laser scanning speed and power) are analyzed. Simulation results show that LLST NDT is a rapid and effective technique to detect the inside defect of the specimen. The relationship exists between ΔT max with the parameters are described. This work lays a theoretical foundation for further application of the technology and paves the way for optimal design of LLST NDT system.