1. Raw Material Preparation: Select high-quality carbon steel (e.g., Q235, A105), stainless steel (e.g., 304, 316), or alloy steel plates that meet standards like GB/T 9119 or ASME B16.5. Conduct strict inspections on chemical composition, mechanical properties, and surface quality to ensure raw material qualification.
2. Cutting: Use plasma cutting, flame cutting, or CNC shearing machines to cut the raw material plates into circular blanks of specified sizes according to the flange's nominal diameter and thickness.
3. Heating: Heat the circular blanks in a furnace to 900-1100℃, ensuring uniform heating to improve metal plasticity and facilitate subsequent forming.
4. Forming: Adopt forging or stamping processes to shape the heated blanks into preliminary flange blanks (including the flange disc and short tube section). Forging enhances metal structure uniformity and mechanical strength, while stamping is suitable for mass production of small-caliber flanges.
5. Machining:- Use CNC lathes to precisely machine the flange's end face, outer diameter, and inner diameter of the short tube, ensuring dimensional accuracy.- Use CNC drilling machines to drill bolt holes on the flange disc, guaranteeing hole position accuracy and perpendicularity.- Finish-machine the sealing surface (e.g., RF, FF) to meet sealing performance requirements.
6. Welding (if needed): For flanges requiring reinforcement, perform fillet welding between the short tube and flange disc according to welding procedures. Conduct non-destructive testing (e.g., ultrasonic testing) to ensure welding quality.
7. Heat Treatment: Carry out annealing or normalizing processes to eliminate internal stresses generated during forging and machining, improving the flange's mechanical properties and dimensional stability.
8. Surface Treatment: Perform anti-corrosion treatments such as galvanizing, pickling, passivation, or painting based on application needs. Carbon steel flanges are often galvanized or painted, while stainless steel flanges undergo pickling and passivation.
9. Inspection: Conduct comprehensive quality inspections, including dimensional inspection (using calipers, micrometers), visual inspection (checking surface defects), mechanical property testing, and pressure testing (for pressure-containing flanges) to ensure compliance with standards.
10. Packaging and Storage: Pack qualified flanges with anti-rust materials and moisture-proof packaging. Store them in a dry, well-ventilated warehouse to prevent corrosion and mechanical damage.