Information about Thermographic Inspection in welded workpieces

Dear, Information about Thermographic Inspection

I'm performing my final project about Thermographic Inspection at Helsinki Institute of Technology. I'm trying to detect faults in steel welded workpieces and I would like to know what are the right sequences and the technique for this inspection. Now, I am really working with the Thermal Camera and it would be helpful if you could answer some questions about the right sequences of the thermal inspection process. How could I measure exactly the emittance of a workpiece? Are there some kinds of emittance lists? If I want to determine the integrity of the fault after the weld has been completed, I will need a post-heating system, what kind of system is the best? Is it enough to heat it with a flash or do I need more heat? How many degrees do I need to heat the workpiece to study it and how much time it takes me the sequences to study the faults? Is better to determine the integrity of the fault during or soon after the weld has been completed? What other very important information I need in this kind of inspection? I look forward to receive notice from you. Thanks a lot for your assistance. Yours sincerely Gonzalo Hern·ndez Camino