High rate (up to 15 A/sm2) anodic dissolution of Ст3 steel in chloride solutions (1−6 M NaCl) was investigated after its electrochimico-thermal treatment (nitriding and thermal treatment). Various potential ranges (or current density ranges) can be emphasized: region of anodic anion activation (sublimiting currents), diffusion limitation area (caused by salt passivation) and transpassive dissolution region. It is shown, that heat treatment influence is the most essential in the region of salt passivation (or limiting current region). The double role of hydrodynamics is revealed during dissolution under these conditions: influence on ion mass transfer rate in solution and on removal of the hard carbon-bearing products produced as a result of selective dissolution of components of nitrided steel. It is shown, that in sublimiting currents and transpassive dissolution ranges specific dissolution rate depends on the nitrogen content of studied steel.