Seamless Tube Manufacturing Process – From Raw Material to Final Product

The seamless tube journey starts with a solid round billet, usually made of:

• Carbon Steel
• Stainless Steel
• Alloy Steel
• Duplex / Super Duplex
• Nickel Alloys

Billets are cut into required lengths (typically 600–1600 mm).

Billets are heated to 1100–1300°C inside a rotary hearth furnace.

Why heat?

• Makes the billet soft
• Allows piercing
• Reduces cracking risk

Heating is carefully controlled using temperature sensors.

(Most important step)

The hot billet is passed between two rotating conical rollers with a piercing mandrel.

Result:

• A hollow tube shell is created
• No welding needed
• Smooth inner diameter

This is what makes seamless tubes different from welded tubes.

Based on final size, the hollow shell goes through:

• Plug Mill – medium-thick tubes
• Mandrel Mill – long-length & high precision
• Pilger Mill – thin-wall, high-accuracy tubes

During rolling:

• The tube is stretched
• Wall thickness is reduced
• Length increases
• Dimensions become uniform

This is where OD & thickness are controlled.

The tube passes through rollers to:

• Correct outer diameter
• Improve roundness
• Adjust wall thickness
• Achieve final dimensions

This ensures tight tolerances.

Heat treatment depends on material:

• Carbon Steel → Normalizing
• Alloy Steel → Quenching & Tempering
• Stainless Steel → Solution Annealing
• Duplex → Annealing

Purpose:

• Improve mechanical properties
• Remove stress
• Improve corrosion resistance

After heat treatment, the tube may bend slightly.

Straightening machines ensure:

• Perfect alignment
• Better roundness
• Uniformity

Tubes are cut into required lengths:

• 4 meters
• 6 meters
• 12 meters
• Custom lengths

High-quality seamless tubes must undergo strict testing:

• Ultrasonic Testing (UT)
• Eddy Current Test
• Radiography (RT)
• Hydrostatic Test

• Tensile
• Flattening
• Flaring

• PMI
• Hardness
• ID/OD measurement

Moksh Tubes follows ASTM, ASME, EN, and API standards.

Finishing options include:

• Pickling & passivation
• Cold drawing (bright)
• Polishing
• Coating (for carbon steel)

Improves appearance & corrosion resistance.

Final checks include:

• Dimensional check
• Visual inspection
• Thickness measurement
• MTC documentation

Packing options:

• Bundles
• Wooden boxes
• Crates
• Export wrapping

Then shipped worldwide.

Used in:

• Boilers
• Heat exchangers
• Superheaters
• Condensers
• Oil & gas pipelines
• Mechanical engineering
• Hydraulic cylinders
• Petrochemical plants

Known for zero weld weakness & high pressure resistance.

• ASTM A106, A53, A179, A192, A213, A335, A333
• Carbon Steel, Stainless Steel, Alloy Steel, Duplex, Nickel
• U-Bend seamless tubes
• Hydro & NDT tested
• ISO & PED certified
• Exports to 40+ countries
• Fast delivery & cut-to-length

Trusted globally for strength & reliability.

The seamless tube manufacturing process is a combination of:

• Precision
• High-temperature rolling
• Expert metallurgy
• Advanced testing

This makes seamless tubes strong, leak-proof, and ideal for extreme conditions.

Moksh Tubes supplies fully-tested seamless tubes for boilers, heat exchangers, chemical plants, and oil & gas applications.