Q345E钢板低温冲击性能影响因素分析

Analysis on the Factors Influencing Low Temperature Impact Performance of Q345E Steel Plate

利用金相显微镜、扫描电镜等手段,针对造成Q345E钢板低温冲击性能较低的原因进行了分析。结果表明,钢中夹杂物、带状组织、贝氏体硬相组织以及晶粒度大小等是影响Q345E钢板低温冲击性能的主要因素。在实际生产中,通过控制钢中夹杂物数量和形态、减轻成分偏析、提高粗轧道次压下率、降低终轧温度、采用层流冷却技术加大钢板冷却强度等措施明显改善了Q345E钢板低温冲击性能,冲击性能平均值由74J提高到了147J,产品合格率大幅提高。

By means of metallographic microscope and scanning electron microscope, the causes resulted in low- low-temperature impact property of Q345E steel plate are analyzed. The results show- that inclusions, banded microstructure, hard bainite phase and grain size are the main factors affecting the low-temperature impact properties of Q345E steel. In the actual production, by controlling the quantity and shape of inclusions in steel, reducing the segregation of composition, increasing the reduction rate of roughing pass and lowering the final rolling temperature, and using laminar cooling technology to increase the cooling strength of steel plate, the low-temperature impact property of Q345E steel plate has been obviously improved. The average impact property has increased from 74J to 147J, and the qualified rate of the product has been greatly improved.