Plastic composite molten steel protective casting sealing method

The invention relates to a sealing structure between a continuous casting steel ladle lower water gap and a tundish long water gap, belongs to the technical field of continuous casting equipment, anddiscloses a plastic composite molten steel protective casting sealing method. According to the technical scheme, the method comprises the following process steps that a, a sealing sleeve (2) is manufactured according to the size of a conic hole in the connecting end of the tundish long water gap and the steel ladle lower water gap, the material of the outer layer of the sealing sleeve (2) is high-aluminum fibers, the inner layer of the sealing sleeve (2) is plastic fireproof pug, and the middle of the sealing sleeve (2) is a graphite coating; b, the sealing sleeve (2) is put in the conic holein the tundish long water gap, and an upper edge (3) of the sealing sleeve (2) is clamped on the outer end face of the tundish lower water gap and compacted; c, one end of the steel ladle lower watergap is fixed in the sealing