https://kl.preprod.corrology.com/library/damage-mechanisms/environment-assisted-cracking/Recent content in Environment Assisted Cracking on Knowledge LibraryHugoenhttps://kl.preprod.corrology.com/library/damage-mechanisms/environment-assisted-cracking/polythionic-acid-stress-corrosion-cracking/Mon, 01 Jan 0001 00:00:00 +0000https://kl.preprod.corrology.com/library/damage-mechanisms/environment-assisted-cracking/polythionic-acid-stress-corrosion-cracking/<h2 id="general-information">General Information</h2> <p>Polythionic Acid Stress Corrosion Cracking (PTASCC) is a form of intergranular cracking that requires coexistence of three elements: a susceptible material (e.g. sensitized austenitic stainless steels and some Ni alloys), presence of polythionic acids and stress.^{<a href="https://kl.preprod.corrology.com/library/damage-mechanisms/environment-assisted-cracking/polythionic-acid-stress-corrosion-cracking/#reference1">1</a>} ^{<a href="https://kl.preprod.corrology.com/library/damage-mechanisms/environment-assisted-cracking/polythionic-acid-stress-corrosion-cracking/#reference2">2</a>} Therefore, PTASCC occurs commonly in areas typically operating in range of 370-843°C (700-1550°F) where sensitization of austenitic materials will progress.^{<a href="https://kl.preprod.corrology.com/library/damage-mechanisms/environment-assisted-cracking/polythionic-acid-stress-corrosion-cracking/#reference2">2</a>} ^{<a href="https://kl.preprod.corrology.com/library/damage-mechanisms/environment-assisted-cracking/polythionic-acid-stress-corrosion-cracking/#reference3">3</a>} ^{<a href="https://kl.preprod.corrology.com/library/damage-mechanisms/environment-assisted-cracking/polythionic-acid-stress-corrosion-cracking/#reference4">4</a>}</p> <p>Polythionic acids, the second element, are typically formed during shutdown or process upset events when oxygen and water/moisture ingress may take place. Stress, the third necessary element for PTASCC and typically arises during cold and/or hot mechanical operations such as welding and bending. The interaction of these three elements is schematically shown in Figure 1.</p>