A specific electrochemical cell for small scale electrochemical testing has been built. The electrochemical cell has been made bearing in mind the microstructural features of the stainless steel weldments and the performance of the design has been verified. Two polarisation methods (potentiodynamic anodic polarisation measurements and cyclic potentiodynamic polarisation measurements) and two reactivation electrochemical techniques (the electrochemical potentiokinetic reactivation test, EPR, and electrochemical potentio-kinetic reactivation double loop test, EPRDL) have been applied to two austenitic stainless steels: AISI 304 and AISI 316L. The results are reliable and have been compared to large scale experiments. Scanning of the welding joints has been performed and the results have been correlated with their microstructural features. It, thus, makes it possible to study the intrinsic heterogeneous microstructures such as the heat affected zone of a welded joint.