6.4　Tundish

6.4.1　The casting speed shall not be reduced before tundish capacity is not reach the conditions of casting with tundish replacement，and the minimum liquid steel depth shall be kept.The capacity of tundish for slab shall meet the requirement that the liquid steel can stay in the tundish for more than 8min.

6.4.2　The shape of tundish shall benefit for distributing of liquid steel and separation of inclusion.The tundish can be provided with slag retaining wall or weir other unit which can improve the flow filed.

6.4.3　The tundish shall be provided with cover for thermal insulation.

6.4.4　The lining of tundish shall have good thermal insulation performance and shall be heated before use.

6.4.5　For the large section square or round bloom，the stopper rod or sliding gate shall be used for controlling the liquid steel flow.For the small section square or round bloom，the length of side shall not be less than 130mm，the stopper rod is preferably used to control the liquid steel flow and the sizing nozzle can be used as well.

6.4.6　When stopper rod is used for tundish casting，the emergency sliding gate shall be additionally provided at the bottom of tundish.

6.4.7　The liquid steel control at the tundish nozzle of slab caster can adopt the stopper rod or triple-plate type sliding gate.

6.4.8　The repairing facilities of caster tundish shall be preferably equipped with aligning unit for repairing of submerged nozzle.

6.4.9　The tundish shall adopt the alkaline working layer and dry material.

6.4.10　For casting of beam blank，the open casting with sizing nozzle or semi-submerged nozzle and the protective casting with submerged nozzle can be used.The double nozzle is preferably used for large beam blank，and the small beam blank can use single nozzle or open casting.