Abstract: Hotrolled coil surface inclusions of low carbon low silicon aluminium killed steel was investigated, and the cause of hotrolled coil surface inclusions was analysised by LF and slab continuous casting production. Through the optimization of steelmaking and LF refining, T.O content was reduced in the steel. Through improving the quality of continuous casting refractory, the secondary oxidation was reduced , and the calcium treatment effect was stabilized. Through improving submerged nozzle structure and mould powder performance, the problem of mould powder entrapment and hotrolled coil surface inclusions were solved.

Key words: low carbon low silicon aluminium killed steel, surface inclusions, calcium treatment, submerged nozzle structure, mould powder performance