Abstract: In order to reasonably choose second refining process of low carbon aluminum killed steel, meet the requirements of clean, efficient, low cost and stable mass production in modern steel plant, the five different second refining processes of LF with calcium treatment, CAS, LF without calcium treatment，RH ordinary treatment, RH light treatment were compared and analysised.  Results showed that RH light treatment technology was more suitable for lowcarbon aluminium killed steel in narrow composition control of carbon content, and the lowest cost was 33.17 yuan/t. The purity of molten steel by RH ordinary treatment process was the best，the total oxygen mass fraction of liquid steel was 16×10^-6 in tunsish, the inclusion amount was 11.2/mm² at the end of refining. RH light treatment process should be preferred, followed by RH ordinary treatment or CAS refining process. Ladle furnace equipment can not use calcium treatment process, but LF refining + calcium treatment has more advantages for steel plant of that need desulfuring and continuous casting nozzle blocking.

Key words: low-carbon aluminium killed steel, high efficiency, low cost, secondary refining