Page Comparison

Table of Contents
indent 25px
exclude

Round tubing is stiffer in torsion while square provides a stiffer beam
Square tubing is easier to fabricate (no ‘fishmouth’ joints) but the tube distorts under load by ‘lozenging’ or ‘panting’.This adds to compliance and may lead to fatigue cracking.
Round tubing is best option, and does not need as much design justification. Harder to manufacture, but will lead to less design and strength issues
May want to consider square tubing for horizontal frame members to simplify suspension mounting points and makes cutting planar joints easier
Triangulation/reinforcement in square tubing can greatly improve structural integrity

...

	4130 Chromoly	Cold Drawn Mild Steel (1018)
Weldability	Recommended to use TIG welding or nickel bronze welding (brazing) Requires pre and post weld heat treatment to normalize the structure after any weld, or becomes very prone to fracturing Can be problematic doing small attachments (brackets + other modifications) on the fly since every weld needs to be heat treated afterwards Recommended to be welded professionally	Recommended to be TIG or nickel bronze welded, but MIG works as well No heat treatment necessary post-welding
UTS (Ultimate Tensile Strength)	590 MPA	420 MPA
Elastic Modulus	Same	Same
Positives	Can use thinner walled sections in areas due to higher strength Better strength to weight ratio Less likely to be dented; higher structural integrity	Less expensive (by 50% approximately) Easier to weld (more options) and no pre or post welding necessary Better to use with a lack of welding experience
Other Teams	Principia

Image Modified

...