Roberts, Matthew Thomas.
Induction Infrared Thermography for Non-Destructive Evaluation of Alloy Sensitization.
Degree: MS, Aerospace and Ocean Engineering, 2019, Virginia Tech
The sensitization of stainless steel describes the process by which a high-carbon steel alloy is heated above a certain threshold (either naturally or artificially) followed by a cooling period during which chromium (one of the elements most responsible for providing stainless steel with its corrosion-inhibiting properties) forms new compounds with the carbon present in the steel. With the chromium being taken from the parent material to form these compounds, the corrosion-resistant properties are compromised, which can lead to corrosion, cracking, and broader failure. Currently, the accepted techniques used to test for the presence of sensitization are qualitative and/or destructive in nature. Attempts have been made to non-destructively detect and characterize sensitization through various means, but all with mixed results. With the use of these high-carbon alloys in a range of industries, a comprehensive, in-place process is desirable.
This thesis will focus specifically on non-destructive evaluation of sensitization seen as a result of welding steel plates using induction infrared thermography (IIRT). This process uses an induction coil to generate heat within a sample whose resulting heat signature can then be detected with an infrared (IR) camera and analyzed. Previous IIRT experimental results have shown higher levels of heating in the HAZ when sensitization is present as it modifies the original microstructure of the material. New IIRT experiments have been conducted on both welded and unwelded 440C alloy samples to establish quantitative data on the heating profiles. These results (in conjunction with the appropriate experimental parameters) were then used to create a numerical model to replicate them. Despite some limitations in populating the model with accurate parameters, the results obtained were in good agreement with the experiments and provide a foundation for future work. Future work will focus on establishing a predictive tool that can detect and quantify the level of sensitization in an arbitrary steel sample in the field.
Advisors/Committee Members: Wang, Kevin Guanyuan (committeechair), Guzas, Emily Leigh (committee member), Seidel, Gary D. (committee member), Gilbert, Christine Marie (committee member).
Subjects/Keywords: Sensitization; Induction Thermography; Non-Destructive Evaluation
to Zotero / EndNote / Reference
APA (6th Edition):
Roberts, M. T. (2019). Induction Infrared Thermography for Non-Destructive Evaluation of Alloy Sensitization. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/90668
Chicago Manual of Style (16th Edition):
Roberts, Matthew Thomas. “Induction Infrared Thermography for Non-Destructive Evaluation of Alloy Sensitization.” 2019. Masters Thesis, Virginia Tech. Accessed July 20, 2019.
MLA Handbook (7th Edition):
Roberts, Matthew Thomas. “Induction Infrared Thermography for Non-Destructive Evaluation of Alloy Sensitization.” 2019. Web. 20 Jul 2019.
Roberts MT. Induction Infrared Thermography for Non-Destructive Evaluation of Alloy Sensitization. [Internet] [Masters thesis]. Virginia Tech; 2019. [cited 2019 Jul 20].
Available from: http://hdl.handle.net/10919/90668.
Council of Science Editors:
Roberts MT. Induction Infrared Thermography for Non-Destructive Evaluation of Alloy Sensitization. [Masters Thesis]. Virginia Tech; 2019. Available from: http://hdl.handle.net/10919/90668