Cause analysis of nonconformity in ultrasonic flaw detection of 500 MPa high performance structural heavy steel plate
In order to find the causes of nonconformity in ultrasonic flaw detection of 500 MPa heavy steel plate,the structure and component of the defects found in ultrasonic flaw detection were investigated by optical microscope,scan electron microscope,EDS analysis and electron probe spectrometer.The results showed that the centerline segregation crack originating from MnS,Nb/Ti inclusions was the cause of nonconformity in ultrasonic flaw detection.By improving the internal quality of the slab with improving steel cleanliness,decreasing superheating temperature of liquid steel,optimizing second cooling technology,and using technologies of electromagnetic stirring and soft reduction,optimizing slab heat process,and stacking slow cooling after rolling,the crack can be prevented.
NETL
NSTL
万方数据
维普
