The application discloses a metallurgical process for reducing point segregation in GCr15SiMn bearing steel
ingot, and the obtained
ingot has high cleanliness, and meanwhile, the
ingot has a composite inclusion with MgO-Al2O3
oxide as a core and MnS as a
peripheral wrapping. The ingot cleanliness requires that the
oxygen content in the steel is controlled to be 6-10 ppm, and the
titanium content is less than or equal to 25 ppm. The composite inclusion has a core
oxide with a size of 0.1-2 microns, and a
peripheral wrapping MnS inclusion, and the total size is controlled to be less than 5 microns, and the
number density is greater than or equal to 10 per mm 2 . The composite inclusion is spontaneously formed in the solidification process of the
molten steel and serves as a
nucleation core of early
austenite, thereby inhibiting the enrichment of solute elements such as C and Si between the solidification front dendrites, and achieving the purpose of reducing the point segregation of the ingot. The EAF-LF-VD-VC process
route is adopted, and the methods such as strictly controlling the end composition of the electric furnace tapping, the
Al content in the whole process, the composition of the refining
slag and the double vacuum process are adopted to realize the purpose.