Precision casting the combined-blowing technology has been widely used in the field of converter, dephosphorization in converter smelting process, it is adopted the two combined-blowing converter joint operation, a combined-blowing converter as a dephosphorization furnace hot metal pretreatment, another combined-blowing converter as decarburization refining furnace.After pretreatment furnace of low phosphorus and low silicon steel, against the decarburization refining furnace steel quality.The decarburization refining furnace slag at the same time, after can handle returned to pretreatment of dephosphorization furnace, used as the slag flux.