Double tube / Inconel 625+Au

Double tube / SUS304 + Cu

Double tube / 9Cr+9Cr

Double tube / SUS304+SUS304

Tapered tube / SUS316L

Thin Tube / SUS316 *Process: Stamping

Thin Tube / SUS316
*Process: Stamping

Inner surfaces mirror finish / SUS304

Surface roughness specified / ≦0.8Rmay

H2-A Rocket / SUS304L

Deformed Tube / SUS321

Deformed Tube / SUS321

High purity AI(99.999%)

High purity AI(99.999%)

Lead materials / Cu+NI

Processing accuracy for inner and outer diameters is 0.001 mm. these diameters can be adjusted by 0.01mm unit

Processing reduces deviations in wall thickness.

Lower frictional resistance improves surface roughness.

Processing enables high reduction, ensuring finer grain & improved mechanical strength.

Key materials

  • Low-carbon steel and stainless steel 
  • Inconel 600, 625, 718, X-750, hastelloy C-276-X, monel, nickel-based alloys including nickel-chromium, etc.
  • Iron-based alloys including incoloy 800 and carpenter 20
  • Copper, aluminum, nickel, titanium, tantalum, and niobium

Scope of standard-dimension manufacturing

  • Outer diameter: 30 mm or less
  • Inner diameter: 3 mm or more
    *Be sure to ask about finer plain pipes with sizes other than those above and subjected to three-roll finishing.

Comparison to electrolytic polishing in inner surface roughness

three-roll finishing

Rz=0.6μm Rz JIS=0.6μm

Electrolytic polish finishing

Rz=0.6μm Rz JIS=0.6μm

What is special ?

more than 50%
This process can accept more than 50% reduction at cross-section.

suitable cross-section
By controlling the tool set, it is possible to obtain a suitable cross-section.

15 meters long
This rolling machine can be produced in the tube 15 meters

Theree-roll rolling Dimensional Limitation (reference only)


Inner Diameter

wall thickness

The following materials are general requirements from customers

  • Stainless seamless tubing (Vacuum melting)
  • Iron-nickel alloy (Invar 36)
  • ≧99.999% High purity aluminum


advantages for tubes made through three-roll cold

Three-roll cold processing ensures high accuracy, dimensional tolerance, and surface roughness not attainable in drawing processes (drawing and cold drawing). Other advantages include the following, making effective use of materials.

1. Tubing using extra-short cutting rods
Tohsei Kokan Cutting materials from rods are used if materials for tubes including special metals are not available. Three-roll cold rolling enables tube processing regardless of quantity if short rods (20 mmL or more) are available. 

Examples include:
♦ 22 mm diameter × 250 mm L → 4 mm diameter × 0.25 mm t × 25,000 mm L
♦ 20 mm diameter × 20 mm L → 5 mm diameter × 0.5 mm t × 600 mm L

Any material can be used except for those with small elongation. This is because of metal characteristics. Examples: tungsten, molybdenum, berylium.

2. Extra-long tube stretching
In drawing, it is not possible to make products exceeding the length of drawing equipment. Longer products become distorted during drawing, causing problems in dimensional accuracy. Three-roll rolling enables rolling of extra-long tubes of 12 M or more while ensuring stable dimensional accuracy, thanks to the special features of this process.

1. Cost rises due to expensive tools and slow processing.
2. Heat treatment in a bright environment is required to maintain high-accuracy surface roughness during heat treatment. Manufacturing is not possible if such heat treatment in a bright environment is not done.
For Tubing using extra-short cutting rods and Extra-long tube streching;
These products are out of stock and are available only by special order (custom-made).
Orders and inquiries: Special Tubes Dept. Phone: +81-3-3668-0381

Tapered tubes

Tapered tube has a thin tip (upper diameter) and a thick base (lower diameter) with a smooth inclination. It can be made into multipurpose cylindrical, square, hexagonal, and octagonal tubes.

Specific Process

Three-roll rolling


Continuous hydrogen annealing

Dimensional inspection

Product Inspection


Main specifications for the production

*Material: Iron-nickel alloy (Invar 36) The Reduction Ratio After Annealing: 45±5%

Measurement and inspection for major dimensions

We have measured and inspected following four dimensions by the automatic checking
machine and sorted out five & NG data which are stored in the PC.



Mean outer diameter / Roundness / Straightness

Measurement and inspection for major dimensions

Every single tubing was packed in slotted tray.
We attached every single written data together with the products for traceability.

Please feel free to ask any questions.
Our experts will answer your questions within 24 hours.