Production process of national standard steel shot "centrifugal method"

　　- Melting: Put high-quality steel, such as high-carbon steel, into a medium-frequency induction furnace or a coreless industrial frequency induction furnace for melting, and melt the steel into liquid under the action of high temperature and high pressure. The temperature and chemical composition need to be strictly controlled during the smelting process to ensure the quality of the molten steel. - Granulation: Pour the smelted molten steel into the bottom

　　-leakage limiting flow pouring cup, and the molten steel flows out through the small holes at the bottom of the pouring cup and flows into the high-speed rotating granulation cup. Under the action of centrifugal force, the molten steel is thrown out and forms small droplets. Due to the action of surface tension, the droplets will gradually become spherical. The speed of the rotating granulation cup will affect the particle size of the steel shot. The higher the speed, the finer the particle size of the steel shot.

　　- Cooling: The granulation cup is usually located above the cooling pool. The steel shot droplets thrown out from the granulation cup fall directly into the cooling pool, and are rapidly cooled and solidified under the action of water or other cooling media to form the initial form of the steel shot.

　　- Heat treatment: Heat treatment of the cooled steel shot is a very critical step. First, quenching treatment is carried out. The steel shot is heated to a certain temperature and then quickly cooled to change the structure of the steel shot and improve its hardness and strength. Then tempering treatment is carried out to eliminate the internal stress generated during the quenching process and improve the toughness and stability of the steel shot.

　　- Screening: The steel shot after heat treatment needs to be screened to screen out steel shots of different particle sizes to meet different usage requirements. Screening can be carried out using equipment such as vibrating screens to divide the steel shot into different grades according to its diameter.

　　- Roundness selection and finishing: During the production process of steel shot, some non-round particles may appear, which need to be rounded to remove irregular particles and improve the roundness and quality of the steel shot. In addition, the steel shot can also be finished, such as removing burrs and impurities on the surface.