Effect of microstructures on SCC of steel: Field failure analysis case study and laboratory test result

Based on continuum mechanics approach, the first step on the modeling of the stress rosion cracking (SCC) is to understand the morphology of the cracks. Later on, it is follow by other considerations such as the chemical interaction, and electron diffusion. This investigates the morphology of the SCC behavior of steels with the main purpose of de doping the basis of computational modeling. It also aims to give the basic sense for pract engineers in the fields as well. It mainly focuses on the morphology of the SCC on basic common microstructures of steel: austenite, ferrite-pearlite, and martensite. objects were taken both from real field works and from accelerated laboratory tests. field samples were extracted from actual failed parts at known operating conditions lifetimes. The laboratory test was an immersion in sodium hydroxide solution. The e experimental parameters were controlled in such away to simulate accelerated field fails with all three microstructures. The crack depth and behavior of the stress corrosion cri (SCC) were then analyzed after immersion test and subsequently, the mechanisn stress corrosion cracking was studied with the focus on their morphological observation, The result shows that each microstructure produces unique shape that can be used basis for computational model creation. Field engineers can also take advantage of results for materials selection. (C) 2011 Elsevier Ltd. All rights reserved.