Originally Posted by ChromePista
Aluminum is also subject to catastrophic failure, so extra material must be added to provide an adequate safety factor."
The holy war over frame materials ignores the fact that Aluminium frames tend to be performance oriented, whereas mass production steel frames are invariably tourer, or burly mountain bike frames.
Steel frames still fatigue and snap. Ritchey made steel mountain bikes intended to last a single season of racing, back in the day. CroMo and the non air hardening Reynolds are pretty notorious for failure just next to the welds.
For a given weight of frame, you get more physical material to use if you build an alloy frame. So you can add heavier butting, or gussets without as much penalty.
But having said all that, I just like the ride of steel. It is much easier for boutique builders to work in, so all the interesting frames are steel.