The ingredient of main inclusions in 38CrMoAl steel by 120 t BOF-LF-RH-CC process is A1

2

O

3

and CaS. The CaS content decreases and the A1

2

O

3

content increases with the time of refining. By calcium treatment experiments

it is obtained that the inclusions of 38CrMoAl steel could not be modified by calcium treatment

on the contrary

more CaS inclusions could be obtained by calcium treatment

leading to nozzle clogging during continuous casting of 38CrMoAl steel. The results of industrial experiments show that a good casting is obtained when the sulfur content after LF refining is controlled at 0.001% ~0.002% and no calcium is added after RH degassing.