Part 2 - Martyr DOMIn Part 1 we talked about the strength differences between 1020 DOM and Chrome-Moly, two materials commonly used in the construction of roll cages. We concluded that the differences were not sufficient enough to justify the price alone, but Chrome-Moly still has a chance here.
In this part, we're going to go through some fabrication differences as well as comments from people who have worked with both materials.
Only as strong as your weakest link.Steel sheets are formed and rolled in highly consistent, standardized conditions. Your welds are not. Generally speaking, the quality of the weld will determine the strength of the frame. Tubes (which are what most racing roll cages are made out of) are great at handling axial forces, but those axial forces must be transferred and redirected at welded joints. You have a ton of forces coming from different directions at a joints, as well as stress from rapid expansion and contraction during welding at joints.
In short, bad welding creates weak points. Choosing an easy to weld material reduces fabrication cost, reduces wear on welding equipment, and increases safety by decreasing probability of error.