Acoustic emission monitoring of slow strain rate tensile tests of 304L stainless steel in supercritical water environment

An experimental set-up has been developed to perform slow strain rate tensile (SSRT) tests on tubular 304L stainless steel (SS) specimens in supercritical water (SCW) environment (550 °C, 250 bar). The supercritical water is circulated inside an internally pressurized tubular specimen mounted into a universal mechanical test rig and heated by a single loop resistance heating furnace. The set-up enables in situ monitoring of acoustic emission and electrochemical potential during the SSRT test. The SCW environment is found to significantly influence the mechanical performance of the material as a result of corrosion processes. A correlation between acoustic emission response and change of electrochemical potential is revealed. The findings are compared with preliminary results of tests performed on bulk SS specimens under the same condition in a commercial autoclave. The advantages and potentialities of both set-ups are discussed.

Research highlights
► Two competitive experimental set-ups for SSRT in SCWR environment.
► In situ acoustic emission (AE) and corrosion potential (CP) measurements.
► Correlation between AE and CP for 304L steel in SCWR environment.