In order to study the mechanism of environmental assisted cracking (EAC) of dual phase stainless steel: DP-3 in 42 and 35 mass% magnesium chloride solution at 90 C, simultaneous monitoring of acoustic emission (AE) and corrosion potential fluctuation (CPF) were attempted. In the 35 mass% solution, we detected vigorous AEs but no characteristic CPF. Contrary to this, RD type CPFs were frequently detected but no AEs in the 42 mass% solution. Referring the previous experimental evidence, the EAC of DP-3 steel in the 35%MgCl_2 solution was concluded to be produced by delayed fracture while that in 42 mass% MgCl_2 solution was by active-path corrosion type SCC.
