Electrochemical and stress corrosion properties of duplex stainless steels modified with tungsten addition

Abstract

Addition of tungsten to duplex stainless: steels (DSS) is known to suppress formation of the brittle secondary phases that may have a negative effect on general corrosion and stress corrosion cracking (SCC) properties. The effects of tungsten addition to DSS on microstructural, electrochemical, and SCC properties were examined. On aging, tungsten addition reduced the amount of alpha-phase precipitation, while enhancing precipitation of the chi phase. The beneficial effect of tungsten substitution for molybdenum in DSS was demonstrated. art electrochemical polarization behaviors and pitting corrosion resistance. Results were more apparent in aged specimens than in homogenized ones when tested at room temperature because of precipitation behavior of the secondary phases. DSS were susceptible to SCC in boiling 35% magnesium chloride (MgCl2) solution but not in boiling 10% sulfuric acid (H2SO4) + 35,000 ppm chloride) solution The beneficial effect of tungsten tungsten addition on SCC properties of homogenized DSS in boiling 35% MgCl2, solution was evident.