Reason Analysis and Improvement Measures for Nonconforming Flaw Detection at 1/4 Thickness of Bridge Plate
In response to the problem of unqualified flaw detection at a quarter thickness of the 20 mm thick Q345qD bridge steel plate,the location of the flaw detection defect was accurately located and sampled.Through analysis methods such as metallographic microscopy and scanning electron microscopy,it is found that the presence of ultra long and ultra coarse point chain oxides containing Al,Ca,and Mg at one quarter of the steel plate,accompanied by hydrogen induced cracks,is the main reason for the unsatisfactory detection of the steel plate.Based on the analysis results,improvement measures have been proposed for the smelting and continuous casting process of bridge steel,such as avoiding aluminum wire supplementation in the later refining stage,ensuring soft blowing time,reducing dry material detachment in the intermediate ladle,and reducing hydrogen content in the steel.These measures have solved the quality problem and increased the qualification rate of bridge steel plates inspection.
bridge slab1/4 of thicknessinconsistent flaw detectiontype B inclusionssoft blowing time
万方数据
维普
