Abstract: The band structure in 42CrMoA hot rolled steel is observed and analyzed by scanning electron microscope (SEM) and energy dispersive spectrum (EDS). The results show that there is a serious band structure in the hot rolled structure of 42CrMoA steel and a second type of band structure such as bainite except ferrite, and the band structure is 3 rating. EDS line scan shows that segregated C and Cr elements seriously among dendrites, which is the main reason for the formation of banded structure. By controlling measure of the superheat of the molten steel in the continuous casting tundish 20 ~30℃. ,the casting speed of 0.75 m/min,the electromagnetic stirring parameter 400 A 8 Hz,and the specific water volume of the secondary cooling decreasing from 0.30 L/kg to 0.25 L/kg and end rolling temperature decreasing from 950 ℃ to 910 ℃ ,the steel banded structure decreases from 3 rating to ≤2 rating.

摘要： 通过扫描电镜(SEM)和能谱(EDS)对42CrMoA热轧态钢中的带状组织进行观察和分析,结果表明:42CrMoA钢热轧态组织中存在着严重的带状组织,并且有铁素体除外的贝氏体等第二类带状组织存在,评定其带状组织为3级。通过EDS线扫描发现C、Cr元素在枝晶间偏析严重,是导致带状组织形成的主要原因。采取控制连铸中间包钢水过热度20～30℃、拉速0.75 m/min、电磁搅拌参数400 A 8 Hz、二冷比水量由0.30 L/kg降至0.25 L/kg和终轧温度由950℃降至910 ℃等措施,使该钢带状组织由3级降至≤2级。

关键词: 42CrMoA钢, 带状组织, 枝晶偏析, 改善措施