碳含量对600MPa级高强钢中心偏析和带状组织的影响

Effect of Carbon Content on the Center Segregation and Banded Structure of the 600MPa Grade High Strength Steel

采用金属原位分析仪、直读光谱仪、金相显微镜以及电子探针显微分析仪对三种不同碳含量试验钢的中心偏析和带状组织进行了检验,结果显示,铸坯中心偏析与成品带状组织之间存在较高关联性,其在横截面上的分布不均匀,边部最轻,1/2处次之,1/4处最严重。钢中的碳、磷、硫、铌、钛元素偏析严重,且随着碳含量的增加而恶化。带状组织在横截面上分布不均,检测标准不完善,带状组织评级存在一定局限性。

The center segregation and banded structure of the tested steels with three different carbon contents were investigated by original position analyzer for metal,direct reading spectrometer,optical microscope and electron probe microanalyzer. The results showed that the center segregation in the slab was highly associated with the banded structure in the finished product. The distribution of the center segregation in the cross section is uneven,where 1/4 width of slab shows the greatest segregation,the center is the next,and the edge hasthe slightest level. The carbon,phosphorus,sulfur,niobium and titanium element in the steel seriously segregate in the slab and with the increase of carbon content the segregation becomes worse. The distribution of the banded structure in the cross section is also uneven. The existing standard for inspecting banded structure have certain limitations for the gradation of the banded structure.