Seamless bends are directional connectors in piping systems, accounting for approximately 80% of pipe fittings. The raw material for rolled seamless bends is round billet, which is cut into meter-long blanks by a cutting machine and then conveyed into a furnace for heating.
Manufacturing Process
Heating:
The billet is heated in the furnace to ~1200°C.
Fuel: Hydrogen (H₂) or Acetylene (C₂H₂).
Precise temperature control is critical.
Piercing:
After heating, the billet is pierced by a pressure piercing machine.
Most common: Tapered roller piercer (high efficiency, superior quality, large expansion capacity).
Rolling/Extrusion:
Pierced billets undergo three-roll cross rolling, continuous rolling, or extrusion.
Sizing & Drawing:
Post-extrusion, the tube is sized using a drawing machine with a high-speed rotating conical drill bit to form the final pipe fitting.
Specification
Material: ASTM A312 TP304H.
Radius: 5D.
Size: 16 Inch (DN 400).
Wall Thickness: 0.5 Inch (12.7mm).
Standard: ANSI B16.9.
