METALLOGRAPHICAL EXAMINATION AND ANALYSIS OF LONGITUDINAL CRACK ON STEEL PLATE

There are some longitudinal surface cracks appear on the continuous casting slab and consequently on the rolling steel plate. By means of the chemical composition analysis, macro-scopic observation and microstructure examination, the results showed that there is oxide in the crack, and the decarburizing and the pit-oxide are exsited in the continuous casting and rolling process. All these factors caused the longitudinal surface cracks appeared on the steel plate after rolling.