Technical terms per letter "F"

Fatigue defect (defects in the metal) is a phenomenon that occurs with a prolonged and strong stress on the metal.

Flange is a protruding part (ledge) of the wheel rim to prevent its derailing

Flange (mech.) is a flat or rectangular ring with evenly spaced bores for bolts and pins, which serves to firm and tight connection of shafts and other rotating parts (flange connection). Flanges are used in pairs (flange kit).

Flange half coupling (mech.) is a part of the coupling rigidly connected with one of the shafts and another half coupling; both half couplings are designed as flanges.

Friction force (mech.) is the resistance force to the relative movement of the contacting surfaces of the bodies. Friction effect is always accompanied by the conversion of the mechanical energy in the internal one, causing heating of the bodies and their environment.