My vote would be for MT using wet fluorescent particles if the material is ferromagnetic.
Best regards - Al
I suggest that you measure in some way (Ultrasound, for example) the deepness of the cracks to see if they have surpassed the boiler mud drum corrosion allowance (i.e., the extra wall thickness calculated to cater for corrosion) and penetrated the wall sound thickness, i.e., the one calculated to withstand pressure.
If this is the case, you should get in contact with the boiler manufacturer or a boiler consultant and ask for specialized advice.
Giovanni S. Crisi
Sao Paulo - Brazil
I am going to second Al and Giovanni. Use the WFMT and UTSW together to help you find were the cracks stop.
By Mikeqc1 
Date 06-01-2011 16:00
Edited 06-01-2011 17:35
use AC current to find surface cracks
if the surface to be inspected is rough i would use dry powder.
Sounds to me like detection is not your problem.
Fixing them will be.
js55
I agree. The first crack should be subjected to forensic failure analysis before chasing down the rest of the cracks. If there is a chemistry induced metallurgical problem, the mud legs will probably need to be replaced. Further crack detection will be unnecessary if failure analysis indicates a systemic metallurgical problem induced by welding practices, or an improper base metal substitution.
I agree with JS55...because your boiler is very old..metallurgical analyzing should be taken.
Best Regard
