A metal's stiffness is totally unrelated to its strength. The Young's Modulus of Elasticity of a metal is the same whether it is in the annealed condition or full-hard. The difference is the amount of force required to yield, or permanently deform the metal. The modulus is different for different metals. "Stiffness" refers to a material's ability to resist deflection within its elastic range.

Mandrel bending requires a mandrel press and all of the related equipment. It also requires the use of annealed tubing, which will be more expensive than unannealed tubing. Taking an unannealed titanium tubing, cutting it up and welding it back together will require less capital equipment (and related expense), but require more labor.

Bending is preferred over weding because over time, the unit could fail due to fatigue. A welded structure will have numerous stress risers due to the geometry of the welds and the notch-sensitivity of the metal. Assuming the designs are adequate to minimize stress points due to heat cycling and vibration, the mandrel bent design should have a better fatigue life.

The greater the magnitude and frequency of deflection of a metal, the sooner the metal will fatigue.

 

hah my $600 invidia > $2k amuse exhaust

Good info never the less, keep it coming; its getting interesting