Should I be using chromoly or mild steel for a rollcage?
4130 chromoly tubing is a superior material for any rollcage or chassis structure. One of the greatest advantages is its strength to weight ratio. You can achieve an equal or in most cases stronger assembly when using an alloy tubing. The weight of an average rollcage can be reduced by almost 40 percent when using appropriately sized 4130 materials. The other great benefit to using alloy tubing is its ability to flex without breaking or bending immediately. The spring-back of 4130 tubing is almost double that of ordinary mild steel tubing, leaving the chassis to flex without breaking. Other than the additional cost, welding chromoly tubing is the only other disadvantage, as it has to be tig welded. Even so, with todays technology of filler materials, as well as square wave welding technology (pulse welding), it is much easier to learn to tig weld. There are also better blends of filler material to create a more desirable weld. All the options weighed, chromoly is the best way to go.
