Determinant parameters of surface morphology to corrosion behaviour of cold-rolled auto sheet steel

Abstract

To elucidate the effect of surface morphology on corrosion behaviour of coldrolled steel, three-dimensional (3D) surface profiles, average corrosion rate and potential differences (PD) for local areas of cold-rolled steel were investigated using a 3D white-light interference surface profilometer, polarization curves and atomic force microscope. Results showed that the linear relationship between surface roughness Sa and corrosion rate, achieved based on polished steels, was not valid for the as-received interstitial-free steels. An innovative surface parameter, the proportion of active area (Pa), was proposed and verified to have a distinct positive correlation with the corrosion rate of as-received cold-rolled steels. Moreover, it was found that the specimen with different surface textures were involved in diverse corrosion stages, and thus, the corrosion rate was determined by different surface parameters. As a result, a three-stage corrosion evolution, including initial dissolution (stage I), peak levelling (stage II) and general thinning (stage III), was deduced, in which Pa and local PD played predominant roles to stage I and stage II, respectively.

Experimental investigation of the effect of skin-pass rolling reduction ratio on corrosion behaviors of AISI 304 stainless steel sheet materials

“…Chen et al [8] determined that the depth of the valleys on the material surface was effective in the corrosion process of IF (interstitialfree) steel in a 3.5 wt% NaCl solution and they stated that it affected the average corrosion rate of IF steel. Cui et al [15] concluded that peaks and valleys on the surface of the material may cause corrosion by forming galvanic cells. Wei et al [16] used composite material in their study and stated that the type of corrosion occurring in this material changed from general corrosion to pitting as the surface roughness decreased.…”