Duplex steel and manufacturing method thereof

The embodiment of the application discloses a duplex steel and a manufacturing method thereof. The manufacturing method of the duplex steel comprises the following steps that molten steel is sequentially subjected to the procedures of converter smelting, LF refining, RH refining and continuous casting, the duplex steel is obtained, cold steel is melted through the RH refining procedure in the smelting interval between melts, the cold steel melting time ranges from 5 min to 20 min, the coal gas flow of the cold steel melting is 500 +/-20 m < 3 >/h, the oxygen-coal ratio is 1.3 +/-0.05, and the height of a top lance ranges from 5.5 m to 7.0 m; and the cold steel is melted in the RH furnace in the smelting interval between the melts, the cold steel gathering amount between the melts is controlled, the whole is broken up into parts, and the cold steel falling accident in the duplex steel smelting process can be prevented. 本申请实施例公开了一种双联钢及其制造方法，双联钢的制造方法，包括以下步骤：钢水依次经转炉冶炼、LF精炼、RH精炼、连铸工序，得到双联钢，其中，炉次间冶炼间隙RH精炼工序化冷钢，化冷钢时