Based on analysis of factors on cutting quality of free-cutting steel AISI 1215

with using the process measures including decreasing carbon content in steel from 0. 094% to 0. 072%

during LF refining using silicon-manganese deoxidizing addition and controlling LF refining end active oxygen content 60 x 10

-6

- 80 X 10

-6

decreasing 140 mm x 140 mm billet mold water rate from 1 900 ~ 2 050 L/min to 1 700 〜1 850 L/min

decreasing secondary cooling water ratio from 1.15 L/kg to 0. 90 L/kg and optimizing rolling process to increase the average diameter of sulphide in steel from original 2.09 μm to 3. 11 μm

the cutting quality of coil of low-carbon high-sulphur (0. 072% C

0. 365% S) free-cutting steel increases markedly and the surface roughness of parts is about 2 μm to meet the requirement of user.