What is Docol Tube R8?

July 16, 2018 @ 9:45:am

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Docol Tube R8 is an advanced high strength steel tube that are engineered to provide a safer, stronger and more consistent alternative to 4130 Cold Drawn Seamless Tube. 

Since its invention in the early 1900’s, 4130 has seen much improvement, other than some refinements in the manufacturing process. Technology never stops advancing, so we set out to find a better and modern alternative to 4130 for the racecars of today and the future. This search led us to the Docol Tube R8, produced by SSAB.

Docol sheet and plate products have been used in the automotive industry for more than 30 years, particularly in applications such as “A” and “B” pillars, door crash bars, roof bows, bumpers, etc., in production cars.

The principal difference between High Strength Steels like 4130 and Advanced High Strength Steels like Docol is their microstructure. 4130 has a single-phase microstructure consisting of ferrite. Docol Tube R8 has a dual-phase microstructure consisting of one-part ferrite and one-part martensite. Ferrite gives Docol its unique forming properties and martensite accounting for its strength.

Click here for more information on Advanced High Strength Steels

Docol is a Quenched and Tempered product going through a special heat treatment in a continuous annealing line to give it its unique properties. Docol is a welded tube produced using a High Frequency weld. Starting out as a flat sheet allows for tighter dimensional tolerances and consistency.


Docol’s key advantages are:

  • Stronger than 4130 by 10 to 15 percent.
  • Heat Affected Zone (HAZ) in Docol is much smaller in area, less brittle and retains better elongation than 4130 typically does.
  • Docol is much more tolerant to heavy fabrication. It does not warp and distort like 4130 and stays more relaxed in tooling and fixtures during fabrication.
  • Greater resistance to fatigue.
  • Docol absorbs energy and presents a more consistent and controlled failure mode.
  • Clean mill finish product – minimal, if any, surface prep required. Docol does not have an oxide or decarb layer and looks like a high quality electric welded tube.
  • Accurate and consistent dimensional and mechanical properties because this material is a rolled and welded strip.
  • Compatible with welding to 4130 and mild steel components.
  • Suitable for TIG and MIG welding.
  • Clean no "scrap based" material resulting in fewer inclusions.