Headers are inspected for cracking in the welds and ligaments. Weld cracking is inspected by using ultrasonics and Wet Magnetic Particle Testing. Wet mag particle is used for OD
cracking while UT
is used for ID
or midwall cracks.
Leaks in Headers can be caused by ligament cracking. Ligament cracking is produced in the bore holes and the stub tube ID
. The cracking occurs due to cyclic events such as startup and shutdowns, transients and thermal shocks. The hottest areas are the most susceptible to ligament cracking, however, there can be exceptions.
We have shown tremendous success in terms of probability of detection and increased productivity using phased array inspection of header welds in lieu of radiography or other techniques during outages. Recent case studies show a minimum of 7 and maximum of fifteen days reduced from the outage schedule resulting in huge cost.
- Steam Line Weld Cracking
Magnetic Particle Testing (MT) is the recommended inspection method for the Inspection of steam lines to detect cracking in the welds. Bending loads can produce OD cracking in the circumferential welds.