Some billets from continuous casting machine do not need cold working, and some are consistent with the production rhythm control of continuous casting and rolling mill. They are rolled after entering a heating furnace above 500 degrees, which is called "hot charging and hot delivery". Some blanks need to be trimmed in cold state because of defects, and some continuous casting machines and rolling mills do not match, so it is necessary to put the blanks on a cold bed for cooling, and then send them to a heating furnace for heating and rolling. The ratio of hot packaging blanks to total blanks is "hot packaging ratio". This is an index to measure the energy-saving effect. At present, the number of new workshops has reached more than 90%.