The process flowsheet of commercial-produced steel 4Cr5MoSiVl (/% : 0.38~0.40C

0.88~0.92Si

0.42~0.44Mn

0.001〜0.003S

0.007~0.014P

5.00~5.55Cr

1.37~1.40Mo

0.98~1.00V

0.015~0.025 Alt) is 65% hot metal +35% scrap-100 t EAF-LF-VD-Φ500mm bloom casting. With the process measures including controlling EAF end [C

]

0.06%~0.10% and end [P

]

0.006%

pre-deoxidizing by adding 1kg/t aluminium block during tapping

controlling LF refining slag basicity 2.5~3.0

soft argon stirring for ≥10 min after feeding calcium wire

VD ≤67 Pa

argon stirring with 100 x2 L/min for ≥15 min

supper heat extent of liquid in tundish 20~30℃

casting mold electro

magnetic stirring with 310 A and 1.5 Hz in casting

shielding casting and casting speed 0.34~0.35 m/min

the [O

]

[N

]

and [ N

]

in 10 heats of steel 4Cr5MoSiVl is respectively 10 x 10

-6

~ 12 x 10

-6

72 x 10

-6

~ 80 x 10

-6

and 1. 2 x 10

-6

〜1.4 x 10

-6

and each index of steel all meet the requirement of specification.