SOME CONSIDERATIONS ABOUT THE USE OF TITANIUM SCREWS

In recent years, the need for lighter vehicles led to the widespread of lightweight alloys, such as titanium, also in the field of bolted connections. Unluckily, the replacement of steel bolts with titanium ones is not quite obvious. The coefficient of friction, a key parameter in bolted joints design, changes drastically when switching from steel to titanium. Differences in the elastic modulus and in the mechanical performances between the two materials, impact on the fatigue behaviour of the joint: appropriate design actions must be taken as a consequence of that. This contribution shows some preliminary results found by the authors about both the frictional and fatigue life behaviour of bolted joints involving titanium screws.