E355 Cold Drawn Seamless Tube Production Process and Heat Treatment

 E355 Cold Drawn Seamless Tube Production Process and Heat Treatment​

​1. Billet Preparation​: ​Material Selection: High-quality carbon steel, alloy steel, or stainless steel billets are sourced.  ​Cleaning: Billets are cleaned to remove surface oxides or contaminants.

​2. Heating​: Billets are heated in a furnace to 1100–1300°C (depending on material) for plasticity and machinability.

​3. Piercing​: A rotary piercer or cross-roll piercer is used to create a hollow tube blank (mandrel bar) at high temperatures. This step forms the initial tube shape.

​4. Hot Rolling (Pilger Rolling)​​ :The hollow tube is elongated and reduced in diameter via a pilger mill, improving dimensional accuracy and surface finish.

​5. Cold Drawing​

  • ​Process: The tube is drawn through a die and mandrel at room temperature using a cold drawing machine. Multiple passes may be required to achieve final dimensions.
  • ​Lubrication: Lubricants (e.g., soap or emulsion) reduce friction and prevent galling.
  • ​Result: Enhanced mechanical properties, tighter tolerances, and smoother surface.

​6. Heat Treatment​

  • ​Annealing:
    • ​Purpose: Relieve residual stresses, soften the material, and improve machinability.
    • ​Method: Tube is heated to 600–800°C, held, then slow-cooled in a furnace.
  • ​Normalizing:
    • ​Purpose: Refine grain structure and enhance strength.
    • ​Method: Heated above AC3 temperature (~850–950°C), air-cooled.
  • ​Quenching & Tempering (Quenched and Tempered)​:
    • ​Purpose: Achieve high strength and toughness.
    • ​Process: Tubes are quenched in oil/water (hardening) and tempered at 500–650°C.

​7. Straightening​ : Tubes are passed through a mandrel straightener to correct any bending or warping.

​8. Cutting​: Finished tubes are cut to required lengths using saws or shears.

​9. Inspection​

  • ​Dimensional Checks: Wall thickness, outer diameter, and roundness via calipers or laser micrometers.
  • ​Surface Inspection: Visual or eddy current testing for defects.
  • ​Mechanical Testing: Tensile, hardness, and impact tests.
  • ​Non-Destructive Testing (NDT)​: Ultrasonic or radiographic testing for internal flaws


​Key Features of E355 Cold Drawn Seamless Tubes​

  • Superior dimensional accuracy and surface finish.
  • High strength-to-weight ratio due to cold working.
  • Customizable properties via tailored heat treatments.

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