Ok did some research but very high level and yes, damping ratio can be changed by the alloy and heat treatment of steel. Whether it is impactful to a kart, maybe.
Articles state that by heat treatment and adding alloys can change damping ratio from .01 up to .07. Below is a response curve of the difference between .01 and .07 damping ratio. The model is a spring, damper, mass system and I would assume the input is either an impulse or step disturbance.
Mind you, this just sets up a potential explanation of why karts and axles change response due to material heat and alloy. (Also donât ask me any more about material science (itâs boring) as I fell asleep during many of those lectures, even sitting in the front row, thinking that would keep me awake.)
Modulus is different between steel phases (ferrite, cementite, martensite) but not by much - most alloys and hardnesses fall between 205 and 210 GPa. More carbon generally gives a lower elastic modulus.
Heat treatment is best done on the whole chassis at once, to get the HAZ properties to match the parent metal. There are a few companies willing to do this. One major competing manufacturer definitely heat-treats frames and hardness testing will instantly reveal not just this but the process theyâre using. Minimum batch size is 40 frames and cost is dozens of dollars per frame. Quench technique and detail design to avoid cracks in stiffness transition areas is fun to work out and good vendors will follow an arrow on a drawing.
Going up to 31.7 x 2.1 mm wall tube helps with fatigue strength; torsional stiffness can then be reduced by bringing the tubes closer together. This is a REALLY sensitive parameter because the parallel axis theorem has an R^2 term! Bending stiffness in the waist is higher.
Factory chassis have a two-year warranty, no-questions replacement for cracks.
