The invention relates to a flow steel tank device. The flow steel tank comprises a liquid steel launder (4), a slagging tank (16), a slagging port (19), an upper slag trap (20) and a lower slag trap (21), wherein the slagging port (19) is positioned on the upper part of the slagging tank (16); the upper slag trap (20) is positioned in the downstream in the slagging tank (16); the lower slag trap (21) is positioned in the upstream in the slagging tank (16); in the flow steel tank device, molten alloy and steel slag which is generated in the smelting process are injected into the slagging tank (16) together; and under the actions of the upper slag trap (20) and the lower slag trap (21), smelted steel slag is blocked in the slagging tank (16), and the formed molten alloy has low turbulence. By the implementation of the tank, scum of liquid steel can be eliminated, large inclusions in the molten alloy can be removed, the continuous casting of amorphous bands is smoother, and the quality of the amorphous bands is improved.