Elastic stress impacting on the rust layer of S450EW weathering steel through magnetomechanical effect

Abstract

Effect of elastic stress on the rust layer of S450EW weathering steel formed in salt-spray was studied through electrochemical methods and characterisations on rust layers. Results show that stratification of the rust layer is mitigated with stress level enhanced on the steel. The stratification involves the magnetic Fe3O4/γ-Fe2O3 phase(s), which tends to segregate in the inner sublayer. The segregation was reduced by stress through a mechanism associated with the magnetomechanical effect. The magnetisation of the steel matrix can be completely regressed by stress up to 200 MPa. Thereby, the magnetic attraction between Fe3O4/γ-Fe2O3 and the matrix can be reduced considerably.