Stress corrosion cracking of 1Cr17Ni2 countersunk screw during the COVID-19 epidemic prevention

Abstract

In the construction of the aircraft, countersunk screws are the preferred fasteners. While during the COVID-19 epidemic prevention, the screws suffered fracture after short service. Results indicated that the SCC susceptibility of screw increased in the K2CO3 and 84-disinfectant environment. The screw exhibited brittle fracture in the 84-disinfectant environment, characterized as necking free and more cleavage planes. The rapid fracture of screw occurred in the 84-disinfectant environment, whether under constant of 12000 N or 20000 N. The screw was significantly degraded during 84-disinfectant dripping-salt spray cyclic test. The corrosion current density increased and the passivation almost disappeared in the 84-disinfectant environment. The SCC mechanism of screw is dominated by the strong oxidation of 84-disinfectant, caused by the cathodic reaction of ClO-. Moreover, the interaction at the bottom of the cross groove between the corrosion dissolution and the stress distribution is clarified by the mechanochemistry.