Smelting method for controlling content of nitrogen in low-carbon steel

The invention relates to a smelting method for controlling the content of nitrogen in low-carbon steel, which belongs to the technical field of steelmaking. The process characteristics are as follows: the smelting slag of a converter is controlled to be 60kg/t steel-120kg/t steel, and the alkalinity is 5 to 7; the circular flow is tapped and strongly deoxidized, and slag is added into the bottom of a ladle before tapping; the arrival temperature of an LF furnace is ensured, the LF furnace refines and the primary heating time is controlled to be 1min to 15min, so as to reduce nitrogen increase; through RH vacuum treatment, the flow of argon is controlled and increased, the vacuum treatment time is more than or equal to 10min and the vacuum degree, and heat insulation agent is uniformly spread on the surface of the ladle after the vacuum treatment; a double-loop suture sleeve and a 3mm-7mm washer are adopted in the casting process and are sealed and protected by argon; and covering agent is added onto the molten steel surface, and the covering effect of the molten steel surface is ensured in the whole casting process. The smelting method for controlling the content of nitrogen in low-carbon steel has the advantages of successfully controlling the nitrogen content of high-grade low carbon steel to be within 30ppm, and providing technical guarantee for the development of high-grade steel, so that the performance of continuous cast ingots and steel sheets is greatly improved.