Corrosion and stress corroson cracking (SCC) susceptibility of duplex stainless steels (DSS) depend on alloy composition, microstructure and temperature. In this study the effect of sulfide containing caustic environment and material properties (DSS composition and microstructure) on the corrosion and SCC of DSS in pulping liquors (synthetic white liquor) was evaluated.
The research was focused to assess the key factors concerning relaxation cracking and how to control it. It included the effect of chemical composition of the base materials (both Fe and Ni base alloys), heat to heat variation, grain size, cold deformation, welding, operating temperature and heat treatments.
Stress corrosion cracking (SCC) of carbon steel in fuel ethanol service has been observed in an increasing number of failures in the last few years. In the presence of oxygen, all of the samples evaluated in this study produced varying degrees of SCC, except for one of the producer ethanol samples. The reason for the high corrosion potential in this sample is still unknown and more detailed analysis of the sample chemical make-up is needed.
A for fitness-for-service evaluation was conducted in simulated seawater injection conditions for three levels of dissolved oxygen (30, 50, and 100 ppb) to assess the effect of upsets in control of the deaeration. Four materials were studied: austenitic UNS S31603, duplex UNS S39274, and two nickel base alloys
Recently Crack Growth Rate and Threshold Stress Intentisity Factor analyses of data from Slow Strain Rate tests have been used for Stress COrrosion Cracking evaluation. This methodology has been discussed in detail based on different analytical techniques and the results from laboratory tests have also been presented.
Experimental results and findings from a joint industry program entitled “Prediction and Assessment of Corrosion in Amine Solvents” conducted over the period from March 2003 to May 2007. An overview of experimental methods, observed results and trends, as well as comparison of predicted corrosion rates to refinery field data.