The production process of tested spring steel 60Si2Mn(/% ：0.58C

1.75Si

0.75Mn

0.012P

0.005S

0.006Als

0.008Alt)is not adding aluminum cake but adding ferrosilicon to deoxidize in an 100 t converter

controlling end [C

]

≥0.08%

and tapping liquid temperature 1620 〜1660℃

LF original temperature ≥ 1500℃

refining time no less than 35 min

RH vacuum ≤100 Pa for，20 min

feeding 100 meters of calcium and silicon wire for modification of inclusions before soft blowing

in whole process shielding-atmosphere casting 150 nun square billet. Analysis results show that the oxygen content in steel reaches the lowest in RH refining process

and rises in tundish stage. In LF refining process

the nitro

gen increase of liquid steel is obvious. Inclusions are mainly composed of A12O3

SiO2

MgO and CaO. During LF refining

the content of SiO

2

decreases to 26.7%

while the content of MgO and CaO increases to 36.7%. Finally

the inclusions in the casting billet are 33% Al

2

O

3

20.7% SiO

2

and 45% MgO and CaO to decrease the high hardness inclusions in steel.