CASE STUDIES OF WELDED STEEL STRUCTURE FAILURES

The contribution summarized several case studies of welded steel structures, which happened in Slovakian water works (dam), transmission gas pipelines, petrochemical industry and at the cement work in last years. The microfractographical analysis gave us a very useful tool to reveal mechanism  and causes of the failures. The main features of cracks predominately in weld joints are illustrated on real cases of breakdowns. Cases of liqiud metal embrittlement, sulphide stress corrosion cracking and hot temperature corrosion are concerned. The present paper dealt with some metallurgical and fractographical features of cracks in the welded joints, which where illustrated on selected real cases of the breakdowns. To distinguish the crack types and to know their causes is very important for adoption of proper measures at repair welding.