Microstructural Examination and Inclusion Analysis of CCS Grade a Ship Steel Weld

A better understanding of the formation mechanism of inclusions should result in decreasing fraction of defects and improving the mechanical property. CCS Grade A ship steel weld was examined by scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS). Inclusions formed and developed through the welding process were investigated. It was observed that accumulated inclusions with irregular morphology generally contain a certain amount of alkaline and haloid elements as well as a great amount of oxygen and carbon. They arise from slag entrapment and their incidence is accidental. Sheet-like oxides are enriched in much higher Al., while globular oxides are enriched in much higher Ti, Mn and Si. They derive from the precedent and bulk deoxidation of the weld pool, respectively. Globular particles of MnS as desulphurization products are also observed.