Method for producing car extra-deep drawing steel through thin-slab continuous casting machine

The invention provides a method for producing car extra-deep drawing steel through a thin-slab continuous casting machine. The method comprises following steps of molten iron pretreatment, converter steel making, LF refining, RH furnace vacuum refining and thin-slab continuous casting; the converter end slag basicity is controlled to 3.5 to 4, the weight percent of FeO + MnO in the LF steel slag is controlled to be smaller than 3%, the molten steel temperature is controlled not to be lower than 1680 DEG C before LF furnace outputting, a calcium ferrite line is fed into molten steel in the RH furnace, argon blowing weak stirring is carried out, the weak stirring time is not less than 8 min, finally, a continuous casting machine with the section specification being 135 mm*1500 mm is adoptedto continuously cast the thin slab, during continuous casting, the slab pulling speed ranges from 0.8 m/min to 1.3 m/min. Protection pouring is adopted, and the problem that in the existing thin-slabcontinuous casting process