Before production begins, raw materials for forged flanges undergo chemical composition analysis and surface defect inspections to ensure the material meets design specifications. Subsequently, the steel billet is heated to the appropriate forging temperature to achieve optimal plasticity, preparing it for the forming process. The billet is then shaped into the basic flange form using either open-die forging or closed-die forging. Open-die forging offers high flexibility and is suitable for single-piece or small-batch production, whereas closed-die forging is ideal for mass production, ensuring dimensional consistency and high efficiency. During the forging process, operations such as multiple upsetting, punching, and expanding steps refine the internal metal microstructure, enhancing mechanical properties and improving the flange's overall strength and fatigue resistance.
Forged flanges also require machining and heat treatment. Machining involves operations such as turning sealing surfaces, drilling bolt holes, and finishing outer and inner diameters to ensure dimensional accuracy and proper fit. Heat treatment processes-including normalizing, quenching, or tempering-are employed to further enhance the material's hardness, toughness, and stability. Finally, after undergoing surface cleaning, anti-rust treatment, and quality inspections (such as dimensional checks, non-destructive testing, and pressure testing), the forged flanges are ready for shipment and service, ensuring their safety and reliability within piping systems.