The main aim of this study was to characterize EN measured during cracking processes, and to compare it with simultaneously measured mechanical changes. Electrochemical noise (EN) measurements have been performed using three electrodes made from the same piece of AISI 304 stainless steel, in one case of the sensitized and in the other case of the non-sensitized type. One of the electrodes, which was subjected to a constant, slowly increasing load (the SRLT test) acted as
a working electrode. Measurements of the extension of a tensile test specimen were performed simultaneously with the EN measurements. The experiments were carried out in a diluted solution of sodium thiocyanate, under open circuit potential conditions, at room temperature.
After the yield point was reached, current and voltage spikes, as well as extension "jumps", were detected, all of them appearing at the same time. This is clear proof that cracking processes can be detected reliably by means of the EN method. The time series of the rate of tensile test specimen extension (so-called crack velocity) were calculated by means of a simple differential equation from the extension time series. The crack velocity maximums, which coincide with the characteristic EN fluctuations, were then compared with the amplitudes of these fluctuations. The results of the comparison indicated that the amplitudes of the electrochemical noise spikes are linearly dependent upon crack velocity. Key words: electrochemical noise, stress-corrosion cracking, SRLT tests, austenitic stainless steel, sensitization, current and potential fluctuations, crack velocity