Pedro Amador - AZZ WSI
Cracking in the weld area of the support skirt to vessel connection is common in DCU vessels. Typically, the welded connection between the support skirt and the vessel incorporates geometry features to reduce the magnitude of stress levels caused by process thermal cycling. Some designs incorporate a tangential skirt to vessel geometry that does not offer any stress reducing features.
A refinery owner was experiencing significant cracking at the skirt to vessel attachment weld location. In addition to compromising the skirt to vessel attachment, the cracking was growing into the vessel pressure boundary. A field implemented process was developed to repair the cracking damage of the vessel pressure boundary and provide a modified attachment geometry to significantly reduce the stress levels at the skirt to vessel attachment location.
The repair was implemented utilizing two automated welding processes that eliminated the need for post weld stress relief at the repair locations.