The invention discloses a flange forging technology and belongs to the technical field of flange production. The technology comprises the following steps of step S1, cutting, wherein a long-strip-shaped blank with a square cross section is cut into multiple square billets; step S2, heating, wherein the square billets are placed in a heating furnace for heating, so that the temperature of the square billets is greater than that of the recrystallization temperature and smaller than that of a solid phase line; step S3, rounding, wherein the square billets are placed in a rounding mold and forgedinto cylindrical billets; step S4, free end finishing, wherein a pressure machine is used for upsetting the heated billets, and a puncher pin is used for punching the billets; step S5, ring grinding,wherein the billets are installed on a ring grinding machine for ring grinding, and center holes of the billets are enlarged; step S6, annealing, wherein the billets are placed in a resistance furnacefor annealing; step S7, turning, wherein a turning lathe is used for turning a flange. The flange forging technology has the advantage of improving the forging efficiency.