Metallurgical flowsheet of tested steel Y1Crl3 (/% ： 0.11C

0.31 Si

1.14Mn

0.024P

0.28S

12.43Cr

0.001 ICa

0. 012A1

0.008 40

Mn/S 4. 07) is 60 t AOD-LF-150 mm x 150 mm billet casting-rolled to Φ12 mm products. In original LF refining without adding Ca

the refining slag basicity is 1.7 ~ 2.1 and the T[O] is 0.012% ~ 0. 015% by only using Fe-Si to deoxidation

while in the improved

adding Ca process

after LF Fe-Si deoxidation adding the Al wire is supplied again to deep deoxidation

the T[O] is 0.007% ~0. 010%

and the Ca wire is fed to modify the inclusions in liquid. Results show that with adding core calcium wire the long stripe sulfide is modified to spherical or spindle sulfide

the max length of sulfide in products reduces to 100 μm from original 160 μmμm

the ratio of spindle sulfide with length/width ≤3 increases to 72.09% from original 52.90% markedly to improve the cutting performance of products.