Méthode statistique de détermination du potentiel de piqûre des aciers inoxydables

Statistic measurement of stainless steels pitting potentials

¹ Centre de recherches d'Ugine Aciers
² Institut de recherches de la Sidérurgie

Abstract

The initiation of pits in neutral chloride media must be considered as a stochastic process and therefore investigated from a statistical point of view.

We describe here an apparatus and an experimental method which permits the determination of the pitting potentials, simultaneously on several samples taken from industrial sheets.

We present an example of measurement, which allows to quantify the effect of the solution chloride content on the pitting probability, in spite of the dispersion on the measured values, which is closed to 100 mV.

Then, we discuss the nature of the statistical laws which account for the observed results. For this purpose, we define an “elementary pitting probability”, which has the dimension of a pits density per unit area.