The GCr15 steel production flow steel is 120 t BOF-LF-RH-CC process. As adding 200 kg aluminum block at BOF tapping for strong deoxidation and controlling the aluminum content 0.030% ~ 0.045% in steel in LF process

at end LF the main inclusions in steel are MgO ·Al

2

O

3

and the MgO.Al

2

O

3

inclusions are removed during RH degassing and the calcium aluminate inclusions are main inclusions in steel after RH. However

but MgO·Al

2

O

3

inclusions are formed again in the tundish steel. Due to the existence of Al-MgO and C-MgO reactions in LF refinin

g process

the MgO ·Al

2

O

3

inclusions could be formed again after LF refining in high carbon aluminum deoxidized GCr15 bearing steel. However

when just adding 40 kg aluminum block for preliminary deoxidation in the BOF tapping process

the amount of MgO·Al

2

O

3

inclusions in steel significantly decrease after LF refining

and the regeneration of MgO.Al

2

O

3

inclusions in tundish steel could be prevented. In addition

adding low titanium and low aluminum ferrosilicon in the LF refining process instead of adding in tapping process effectively control the amount of MgO · Al

2

O

3

inclusions in steel.