Delayed fracture on self-tapping screws

Abstract

Hydrogen induced fracture on two different screw stocks (UNI C16 modified and UNI C23BKD) was analysed.

Fracture toughness has been evaluated by area reduction measurements carried out on carbonitrided specimens, fractured by tensile test, and rupture angle measurements on specimens broken by torsion tests.

Specimens were cathodically charged with hydrogen (current density = 10 mA/cm²).