Abstract

We investigate the efficacy of using induction infrared thermography (IIRT) to detect sensitization in chromium steel. Sensitization refers to the precipitation of certain compounds — Cr23C6 in chromium-steel — at grain boundaries due to cyclic temperature variations, which makes the alloy susceptible to corrosion, environmentally assisted cracking (EAC), and broader failure. In this talk, we first present an experimental study to demonstrate the feasibility of the method. We use welding to induce sensitization in chromium-steel specimens (in the heat-affected zones (HAZ) adjacent to the weld) and conduct IIRT testing using an inductor wand and a FLIR SC8203 infrared camera. Next, we present a computational study to simulate the experiment and compare with the experimental results. Specifically, we present a thermo-electro-magnetic model including Fourier’s law of heat conduction and Maxwell’s equations for predicting the electromagnetic field caused by a sinusoidal excitation current through the inductor coil. We also introduce an empirical model to relate the density and thickness of sensitized grain boundaries with the local increase in eddy current density which are solved using the commercially available software COMSOL. Finally, we compare the experimental and computational results and discuss the capability of the proposed IIRT method for detecting sensitization in chromium steels.

How to Cite:

Roberts, M. ., Wang, K. . & Guzas, E. ., (2019) “Induction infrared thermography for non-destructive evaluation of alloy sensitization”, Review of Progress in Quantitative Nondestructive Evaluation .