齿轮钢大圆坯的铸态组织及轧制遗传性

基于φ500 mm大圆坯连铸连轧生产22CrMoH汽车桥齿钢的工艺,通过对铸坯低倍组织及高倍金相组织、轧后带状组织系统分析,开展了齿轮钢大圆坯铸态组织及轧制遗传性研究。研究发现,22CrMoH齿轮钢连铸大圆坯近表面细晶区、柱状晶区、中心等轴晶区的枝晶尺寸存在明显差异;自表面至芯部二次枝晶间距逐渐增加,退火状态下枝晶主干位置以铁素体为主,枝晶间以珠光体为主;轧后带状组织形态主要受铸态组织二次枝晶间距和轧制变形的影响;轧后退火态铁素体带宽自表面至芯部呈现增加趋势。

Cast macrostructure and rolling genetics of gear steel round bloom

Based on the production process of 22CrMoH automobile gear steel by continuous casting and continuous rolling of 500 mm large round billet, through the analysis of low-magnification structure, high-magnification metallurgical structure and strip structure of rolled billet, the as-cast microstructure and rolling of gear steel large round billet were carried out. It was found that the dendritic size of the 22CrMoH gear steel continuous casting large round billet were significantly different in the near surface fine grain region, the columnar crystal region and the central equiaxed crystal region. The secondary dendrite spacing from the surface to the core gradually increases, and ferrite dominated the main dendritic trunk and pearlite dominated the dendrite. After rolling, the banded structure is mainly affected by the secondary dendrite spacing and rolling deformation of the as-cast microstructure, and the bandwidth of annealed ferrite increased from surface to core after rolling