Microstructural and electrochemical characterisation of heat-treated 347 stainless steel with different phases

摘要

Type 347 stainless steel was solution annealed at three different temperatures (1100,1250 and 1300 ℃) followed by ageing at 650 and 750 ℃. This was done to study the phase transformations that may occur in stainless steel 347 during welding and/or subsequent ageing. The microstructural examination showed chromium carbide and a phase formation at the grain boundaries after ageing. The electrochemical behaviour was evaluated by double-loop electrochemical potentiokinetic reactivation test and anodic polarisation in HC1 solution. Chromium carbide precipitation caused large increase in the degree of sen-sitisation, while a phase had the major effect in decreasing the pitting resistance.