Most of Racetech Steel's metal is USA or European origin. Therefore the dimensions are almost all imperial dimensions. For your convenience we have converted them to metric equivalents,  eg. a 1" diameter may be
referred to as 25mm, the actual measurement will be 25.4mm.

Technical terms and abbreviations

  • Tube: is often referred to as Pipe. The difference is, pipe is used as a vessel to transport liquid or gasses through. In this instance the inside diameter is what is important. Where as tube is used in structures. Since the engineers work typically with the outside diameter, it has become the critical measurement.
  • MPA: Mega Pascals.
  • 650 MPA: The minimum tensile strength of Chromoly 4130.
  • 350 MPA: The minimum tensile strength of our roll cage mild steel 1020 and 1026.
  • Tensile strength: The resistance to stretch (tension).
  • Yield strength: The MPA it takes to deform.
  • The difference between minimum (tensile) and ultimate (tensile): Minimum is what the material must be to pass specification. Ultimate is what the material actually is. i.e a Racetech 350 tube can be around either 400 MPA or as high as 750 MPA, depending on the quality and processes the material goes through.
  • Elongation: The ratio of yield and ultimate (actual) tensile. This ultimately determines the malleability of a metal.
  • CDS: (Cold Drawn Seamless)- Tube made from a pierced solid then drawn over a mandrel to size
  • CDW: (Cold Drawn Welded) Made from a welded strip, then drawn to size.
  • DOM: (Drawn Over Mandrel), same as CDW or CDS.
  • ERW: (Electric Resistance Welded) Made from a welded strip, rolled to size.
  • Precision Mechanical Tube: Tube made to tighter tolerances with special alloys.
  • Alloy: A metal made from a cocktail of raw elements.
  • Element: A substance in its most simplest form.
  • 4130: A hi-tensile Alloy steel manufactured to the standard SAE-4130. Also known as Chromoly, CrMo, Chrome-Moly, Chromium Molybdenum.
  • Periodic table of the elements: A fancy name for a list of all known elements in solid liquid and gas.
  • Mil-T6736B: 4130 Specification that meets Aircraft and SFI minimum tests.
  • ASTM-A519: A specification for precision cold drawn seamless tubing regarding OD, WT and straightness tolerances.
  • OD: Refers to the 'outside diametre' of a tube.
  • ID: Refers to the 'inside diametre' of a tube.
  • WT: Refers to the 'wall thickness' of a tube.
  • CrMo: Sometimes referred to as Chromoly, Chromolly, Cromoly, Chrome-Moly, Chrome Molly; Short for Chromium-Molybdenum steel alloys of which 4130 and 4140 are common grades.

Below is a rough table displaying the mechanical properties and chemical makeup of the popular steel tubes we stock. Each batch will display its own unique properties but you can use this as a guide.

CDS 1020 CDS 1026 CDS 4130
  ASTM-A519 ASTM-A519 AMS-T-6736
Tensile Strength 540 705 900
Yield Strength 415 615 720
Elongation 23% 23% 20%
C Carbon 0.2 0.26 0.3

CAMS roll cage requirements

Keep an eye on this space for more interesting technical bits in the coming months.

Dragcar rollcage

Literature & Media

A very informative articles we have come across from Lincoln Welding, relating to welding 4130 Chromoly

Racetech Catalogue 1.171 Racetech Catalogue 1.171 (4993 KB) 4130 Weight Calculator 4130 Weight Calculator (14 KB) lincoln lincoln (99 KB)

Below is an informative guide to welding 4130 in race car application