Steel for barrel of fire extinguisher as well as preparation method and application of steel

The invention discloses steel for a fire extinguisher cylinder and a preparation method and application thereof, and relates to the technical field of steel smelting. By controlling the element composition of a continuous casting billet and controlling the content of carbon and manganese, it can be guaranteed that the steel still has high strength under the high-temperature condition, when a fire extinguisher barrel is prepared, high-temperature rotation pressing-down indentation is eliminated, and meanwhile the steel has good welding performance and formability while the strength of the steel is guaranteed. The microscopic morphology of the prepared steel can be controlled by controlling the temperature parameters of the annealing process and matching with the element content in the continuous casting billet, heat preservation is conducted at the temperature of the soaking section provided by the invention, carbon dissolution in the steel reaches balance, and the situation that the strength of the steel is a