The production flowsheet of pilot-produced steel 80MnCr (/%: 0.79~0.81C
0.92~0.97Mn
0.26~0.32Si
0.009~0.017P
≤0.005S
0.92~0.97Cr
0.06Mo
0.03~0.05Ti
0.027~0.032Al
0.0004~0.0012O) is BF-70t BOF-LF-VD-Φ450mm Round bloom casting-rolling to Φ90mm bar. With the process measures including controlling BOF end [P]≤0.015% and end [C]≥0.12%
pre-deoxidizing with 1.5kg/t steel cored aluminium at tapping
deoxidation by feeding aluminium wire in LF
refining slag basicity N4
after VD feeding calcium wire
mold-EMS and end-EMS in casting
the rating units of inclusions in steel are heavy series 0 and thin series ≤0.5
the rating of macrostructure are central porosity ≤1.5
general porosity ≤0.5
central segregation ≤0.5 and ingot square-segregation zone 0; and the qualified rate of steel products by ultrasonic nondestructive measuring is up to 93.07%.