Effect of various phase fraction of bainite, intercritical ferrite, retained austenite and pearlite on the corrosion behavior of multiphase steels

The work discusses the corrosion behavior of a set of newly developed high strength and highly ductile multiphase steels consisting of various fractions of bainite, intercritical ferrite, retained austenite and pearlite from the composition 0.67 % C, 1.71 % Si, 0.86 % Mn and 96.69 % Fe (wt.%). The steels were made by various combinations of continuous cooling in the ferrite-pearlite zone followed by austempering. Multiphase interaction and rust constituents uniquely control the corrosion of the steels. At a particular isothermal temperature, initial increase in corrosion rate with increment of continuous cooling time is followed by decrease in corrosion rate once pearlite starts appearing.