The chromium adds strength hardenability and a level of corrosion resistance to mild carbon steel though chromoly is not as corrosion resistant as stainless steel.
Chromoly vs mild steel weight.
In this short video tim mcamis explains some of the differences between 4130 chromoly and mild steel tubing for use in drag race chassis construction.
Chrome moly is the abbreviation for chromium molybdenum and it is an alloy steel.
In conclusion if weight reduction is important in the design of your chopper then chromoly tubing is an excellent choice.
The elongation values of the docol tubes are better than in the 4130 chrom moly tubes.
A stronger mild steel rod such as 80s d2 can be used to weld thin walled chromoly without post heat but 70s rod is a better choice for frames as the increased ductility will serve better at absorbing repeated impacts.
And wall thickness a chrome moly tube weighs the same as a mild steel tube.
It was designed for and is used extensively in the aircraft industry due to it s high tensile strength and torsional load ratings.
Chromoly is a chrome alloy steel with a medium carbon content and 8 1 1 molybdenum for strength.
Given the same o d.
The docol tubes have slightly lower yield strength but higher tensile strength.
One of the never ending topics of conversation is the use of 4130 steel over mild steel in professional drag racing builds.
Mild steel with it s thicker wall you don t really want to fit as tight as moly using either a little larger fitted gap or a larger chamfer at the gap to aid heat penetration without cranking up the machine a bunch so less time spent.
The mechanical properties of the docol 800 dp tubes are very similar to the 4130 chrome moly tubes.
Chromoloy tubing is made from a family of low alloy steels that contain chromium and molybdenum sae 4130 or 4140 along with the iron carbon and other elements.