高纯净度汽车用非调质钢的试验研究

Investigation on Production of High Purity Hot Forging Steels for Automotives

通过采用提高电炉炼钢铁水比、强化脱磷、高碱度精炼炉渣、直接脱氧和强扩散脱氧等工艺措施，生产出了ω（[P]）=0．005％、ω（T[O]）〈0．001％的高纯净度非调质钢。研究中发现，在铸坯柱状晶与中心等轴晶带的边界处，C、P、S、Mn发生较大的正偏析。钢中的非金属夹杂物主要有MnS-MnO类夹杂物和TiN—VN类析出物2个类型，其中MnS-MnO类夹杂物中MnS的质量分数为70%～81％，为塑性夹杂物。TiN—VN类夹杂物中TiN的质量分数为72％～85％，在轧制过程不变形。

High purity hot forged steel for automotives with 0. 005% of w（[P]） and less than 0. 001% w（T[O]） has been produced by means of increasing hot metal charging ratio, strengthening dephosphurization in EAF, strong direct and indirect deoxidations, etc. It was found that more segregations of C, P, S and Mn occurred at the boundaries between the columnar grains and equiaxed grains. There were mainly two types of non-metallic inclusions in the steels, which were the MnS-MnO typed inclusions and TiN-VN typed inclusions. The MnS-MnO type inclusions contained 70%-81% MnS and were plastic inclusions. While, the TiN-VN type inclusions contained 72%-85% TiN and were unformable inclusions during hot deformation.