Containers subject to stress corrosion
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What does it mean that, as specified in Figure 8.2.2.2 of GB150.4-2011, containers subject to stress corrosion need to undergo heat treatment? What are the media subject to stress corrosion?
Carbon steel: Sodium hydroxide solution, chlorine solution, nitrate salt solution, H2S aqueous solution, seawater, marine atmosphere, and industrial atmosphere. Austenitic stainless steel: Chloride aqueous solution, seawater, marine atmosphere, high-temperature water, humid air, hot NaCl, H2S aqueous solution, heavily polluted industrial atmosphere. Martensitic stainless steel: Chlorides, seawater, industrial atmosphere, acidic sulfides. High-strength steel for aviation: Marine atmosphere, chlorides, sulfuric acid, nitric acid, phosphoric acid. Copper alloys: Water vapor, humid H2S, ammonia solution. Aluminum alloys: Humid air, NaCl aqueous solution, seawater, industrial atmosphere, marine atmosphere
Among the three elements of stress corrosion, the medium is the most complex... generally including alkalis, acids, ammonia, hydrogen, sulfides, and carbonates……
To resist stress corrosion SCC, heat treatment is carried out to eliminate residual stresses (or processing stresses), as stress corrosion is particularly sensitive to tensile stresses.
Search within the document: Recognition of damage modes in pressure equipment. This is a draft version of the GB standard that is about to be issued; understanding its contents is of great importance for the management of equipment and corrosion. It provides detailed analyses of over eighty different failure modes, including various types of SCC. This standard is based on API571 but is not limited to it.