Given that a piece of 3/4" x 0.035" 4130 steel tube now costs $7.50 a foot, I have been looking at other options. DOM tubing is starting to look attractive for certain application. It is already used for a wide variety of structures (race cars and motorcycles for example) and in an application such a a steel tube fuselage frame I can't really see much objection to it. Most tubes are sized for buckling loads for which the lower ultimate strength doesn't really matter, since the modulus of elasticity is the same for both types of tubing. (Or close enough.)
Trying to find reliable property values for these tubes is a little difficult; some suppliers are decidedly optimistic with their values, but even if considered an average mild steel (say 60kpsi ultimate, 40kpsi yield) it would be a useful material. For bending applications, I'd still go for 4130.
Trying to find reliable property values for these tubes is a little difficult; some suppliers are decidedly optimistic with their values, but even if considered an average mild steel (say 60kpsi ultimate, 40kpsi yield) it would be a useful material. For bending applications, I'd still go for 4130.