关键词: GCrl5轴承钢, 大颗粒DS类夹杂物, BOF-LF-VD工艺, , 示踪实验

Abstract: The production flowsheet for steel GCrl5 is 90 t converter-LF-VD-250mm x280mm bloom casting-rolling process. With adding aluminium to deoxidize during converter tapping and refining by high basicity slag [/% : 55 〜 58CaO, 3 ~ l0MgO, 12~ 16SiO₂, 16~24A1₂O₃, ≤ 1 (MnO + FeO) ], the T[ 0] after feeding Al in LF process is 14 x 10^-6 , and the T[O] at end of LF refining is 10 x 10^-6. With using SEM (scanning electron microscope) and EDS ( energy dispersive spectroscope) to study the composition distribution of unqualified large DS series inclusions in rod products, it is found that at the center of inclusion the main composition is compound oxide CaO-MgO-Al₂O₃，outside is wrapped by a small amount of CaS, in this oxides the A1₂O₃ content is up to about 65% with even distribution, the CaO content is about 20% and the MgO content is about 15%. Statistics analysis results show that after VD vacuum treatment the number o£ diameter more than 13μm  large inclusions per mm² increases to 7, after soft stirring that decreases to 2. 1, arid in rod products the one of three large inclusions come from ladle slag.

Key words: Bearing Steel GCr15, Large DS Series Inclusions, BOF-LF-VD Process, Tracer Experiment