LF furnace (LADLE FURNACE) is a ladle refining furnace, which is the main refining equipment in steel production. The LF furnace refining mainly relies on the white slag in the barrel, and in a low-oxygen atmosphere (oxygen content is 5%), argon gas is blown into the barrel to be stirred, and the graphite electrode is heated to refine the molten steel passing through the preliminary furnace. Since argon agitation accelerates the chemical reaction between the slag and the steel, the temperature compensation is performed by arc heating, which can ensure the refining time for a long time, thereby reducing the oxygen and sulfur content in the steel, and the inclusions are rated according to ASTM. ~O. Level 1. The LF furnace can be combined with an electric furnace to replace the reduction period of the electric furnace, and can also be combined with an oxygen converter to produce high-quality alloy steel. In addition, the LF furnace is still a continuous casting workshop, especially the indispensable control components, temperature and equipment for preserving molten steel in the alloy steel continuous casting production line. Therefore, the emergence of the LF furnace has formed a new production line of LD-LF-RH-CC (continuous casting) new high-quality steel. The reduction and refining of steel in this joint production line is mainly done by LF furnace. The steel grades treated by the LF furnace involve almost all steel grades from special steel to general steel. The visual quality control needs in production, and different process operation systems are adopted. Among various secondary refining equipments, the LF furnace is cost-effective.