Research On The Quality Control Of Q345 Low-alloy Steel Plate

Nowadays,with the development of bridge construction,steel construction for infrastructure construction,shipbuilding industry,petroleum and natural gas mining and transportation,the demand for steel plate were strongly pulled on Especially in the major manufacturing sectors which need high performance of the steel,such as advanced mechanical manufacturing,high pressure vessel manufacturing,and the construction of power station.So it is necessary to develop a stable and efficient production technology for steel plate with excellent performance.Due to the effects of lots of processing parameters on the performance of sheet metal;it is difficult to control the quality of the steel plate simply by improving and optimizing the manufacturing technique.Against this background,more attention should be paid to the systematic analysis of manufacturing process and the improvement of each important step in production.In this paper,The typical surface and internal defects of the plate samples and its formation mechanism,such as surface longitudinal crack,transverse crack,internal flaw and abnormity of physical-mechanical characteristic,were investigated.Furthermore,the formation mechanisms of the defects at different stages of continuous casting,heating and rolling were identified.The microstructure,characteristics and the causes of the typical defects in plate steel were analyzed.The disadvantages of defects and the preventive methods were described in detail,which plays an important role in the judgment of common product quality,the causes of defects and the corresponding measures of decreasing the number of the defects.