Yeah, pretty new around here, but been building and welding for a while now, and I've heard the question a hunert times before. My answer is way far from being scientific, with all the stress ratios, shear factors, and all the mathmatics... just what I've been exposed to, seen, done, and experienced for going on 40+ years now. I'm sure there will be some engineers to explain alll the details I left out...LMAO, and that's cool
JJust wanted to pass it along to maybe help a new guy with a welder trying to figure out what to buy for his next project...
They ain't the same animal. They have definite different tensil stregths, and different deminsions.
PIPE
For example 3/4" black iron, available at Lowe's, Home Depot, etc...is designed to carry gas, oil, water, and even steam. It's strength is based upon bursting pressure, as for dimension, 3/4" B.I. is approximately 1.00" O.D.
ALL black iron pipes have this descepancy. Schedule 40 being the lightest you'd want to use in any frame constrction( and the preferred wall thickness) Schedule 80, the heaviest, thickest wall, nearing 3/16" thick.
TUBING
ERW... is a welded seam pipe, most commonly used by motorcyle manufacturers on productiom bikes, scooters, golf carts, also hand trucks, framing and bracing. Stick or M.I.G. welding work great. MMinimum thickness for frames .125"(1/8)
DOM... Drawn over mandrel, non-welded fabication of pipe, mucho stronger, "Higher End" vehicles and equipment. Stck or M.I.G. also great, gassless M.I.G., beautiful, and strong Minimum thickness for frames .125" (1/8)
CHROMOLY... better know your welding if you mess with this stuff, beautiful welds can lead to ctystallization cracking later. HELI-ARC....aka T.I.G. only! Minimum thickness, I've seen some air frame and fuel dragsters down to .090" possibly thinner...great weight saver, strong as all get out, EXPENSIVE, and touchy when welding.
All tubings bend GREAT on a mandrel bender($3500.00 and MORE), can be touchy on the HF Pipe bender($129.00), I've ruined more than a couple of pieces
Pipe bends good, on a pipe bender, don't rush it, go slow... I HATE bending anything!