Low Cr (3 to 5%) bearing steels have been developed and used in CO2 environment as materials to meet "Fitness for Purpose". However, the SSC and SCC resistance of low Cr bearing steel have not been clarified. This paper presents the effect of carbon content, microstructure, and tempering temperature on the SSC and SCC resistance as well as CO2 corrosion resistance of low Cr steel (3%Cr steel).
Prestressed concrete cylinder pipe pipeline sections projected to exhibit wire breaks were detected - and one not so - were excavated, removed, inspected, and dissected. Corrosion had initiated upon the inner surface of shorting straps and spread to the prestressing wires. A mechanism for this corrosion is presented and the findings discussed.
Chloride induced corrosion is recognized as a significant disease in the nation's concrete infrastructure. This paper will provide an overview of the various corrosion mitigation techniques available and then focus on two innovative methods of using discrete anodes embedded within the concrete to provide corrosion protection to existing structures.
Results of inhibitor performance at slug flow in a 101.6 mm inner diameter horizontal pipeline. Electrochemical Impedance Spectroscopy (EIS) and scanning electrom microscope (SEM) techniques are used to reveal that the strong bubble impact, high shear stress and turbulent intensity are the reasons for a poor performance of inhibitor.
This presentation summarizes the development and expansion of a comprehensive information system for corrosion of metals and alloys in high temperature gases. New insights in analysis of thermochemical data for the Fe-Ni-Cr-Co-C-O-S-N system are being compiled. Corrosion mechanisms emphasized are oxidation, sulfidation, sulfidation/oxidation, and carburization.
A case history is described involving microbiologically influenced corrosion (MIC) of AISI Type 304L stainless steel piping failure after being in contact with untreated stagnant, low chloride potable water for nine months. Specialized microbiological analysis techniques, including scanning electron and optical cmicroscopy, were used in the failure analysis.
This research effort was designed to evaluate stress-oriented hydrogen-induced cracking (SOHIC) behavior of a broad range of advanced plate steels (0.002 wt% sulfur) that were not produced to enhance resistance to cracking in wet H2S environments. Test results indicated that SOHIC resistance was adversely affected by microstructural (ferrite/pearlite) banding. However, additional factors also played a role in determining SOHIC behavior.
Austenitic stainless steels are susceptible to caustic stress corrosion cracking (SCC) above 121°C. When sulfides are present in caustic solutions the SCC has been reported to occur at lower temperatures. This paper discusses a study of the role of sulfide in caustic solutions on SCC of austenitic stainless at T=~50°C.
Analysis of a UNS N08800 hydrogen unit preheat tube that failed in service. Based on chemical and metallographic analyses the failure was attributed to liquid metal embrittlement by zinc. The zinc source is thought to be the Cu/Zn catalyst for the low temperature shift converter located downstream of the preheat tubes.