In consideration of easier nozzle clogging and difficult control of bloom quality for casting pipe line steel X52 ( % : 0.14~0.18C
0.30〜0.50Si
1.25〜1.40Mn
≤0.025P
≤0.025S
0.03~0.06Nb) in casting by square round bloom caster
the pipe line steel X52 is produced with using the technoiogy including according to carbon content in liquid adding 200 ~ 500 kg/heat Fe-Al deoxidizer at tapping of BOF
refining by high basicity slag (% :%:≥70CaO、≤5Al
2
O
3
、≤5SiO
2
、≥5CaF
2
、≤5MgO、≤0.05N) in LF process
and soft blowing argon for 5 min after refining. Results show that the average desulphurization rate is 37%
in steel the S ≤0.011 % and P ≤0.015%
the surface quality of Φ200 mm round bloom is nice and the rating of each item of macro-etch test is less than rating 1.0