Abstract: As raw product，steel ingots play an irreplaceable role on manufacturing key forgings in some fields of the equipment manufacturing industry. The manufacturing process of top-poured steel ingots of 30Cr2Ni4MoV and bottompoured steel ingots, covering 20MnMo, 38CrMoAl low alloy steel and H13 mould steel, were researched to improve the purity of molten steel, which would promote domestic development of technology in steel ingots. Among manufacturing process, EAF→LF→VD→VP process route was adopted by toppoured steel ingots; EAF/added with convert steelmaking process →LF→VD→IC process route was adopted by bottompoured steel ingots. Results showed that lower total oxygen content w(T.O)≤12×10-6 in 30Cr2Ni4MoV steel was obtained by adopted process of vacuum carbon deoxidization in the location of VD, VP in comparison with common aluminum deoxidization, and the special requirement of chemical composition on w(Si)≤0.03 %,w(Mn)≤0.05 %,w(Al)≤0.005 % also could be reached, and sensitivity coefficientJ of tempering embrittlement also could reach to 3.4;w(T.O)≤10×10-6，w(S)＜0.001%,lower content of phosphor and nitrogen were obtained in high-purified bottom-poured steel ingot, involving low alloy and H13 mould steel, by applied with converter process of electric furnace and control oxygen technology in whole operation.

Key words: steel ingot, top-poured steel ingot, bottom-poured steel ingot, manufacturing process of highpurified ingots