The challenge in the shipping market
European yards are competing with low wage countries in the Middle and Far East. Only those shipyards who are able to fabricate ships in an efficient way or those who are specialized in a typical class of ships, will survive. An efficient method is prefabrication in compartments and subassemblies. However problems are effected after welding in terms of distortion at the steel plates, brackets, stiffeners at the hull construction parts.
Repair and strengthening of welded details are thus of great importance in order to extend the life time and safety of existing ships, FPSO’s and semisubmersibles.
“Almost all stiffeners, brackets and other attachments in ship hulls are joined by non-penetration fillet welds for fabrication reasons. However, the ends of these attachments show frequently high stress concentration due to their geometrical shape and loading. Fatigue cracks may initiate here not only from the weld toe, but also from the non-welded root gap” (Wolfgang Fricke, 2002)
Benefits of UIT
UIT extends the fatigue life of welded details, not only for new manufactured structures but also for existing structures.
  • application to strenghten or rehabilitate the welt
  • Save weight in the hull
New build ships
UIT treatment directly applied after welding enhances the distortion effect. It also allows reduction of material with the same calculated fatigue life.
Typical application
UIT as alternative to flame straightening. The latter is an uncontrolled process and requires excellent craftsmanship. UIT reduces welding distortion in joints with plate thickness up to 10mm.