Environment Assisted Cracking on Knowledge Library

Chloride Stress Corrosion Cracking

Mon, 01 Jan 0001 00:00:00 +0000

General Information

Mechanism

Key Variables

Temperature

Species

Metallic materials impacted by Chloride Stress Corrosion Cracking

Flow regime

Calculation Tools

The intention of these tools is to provide quick corrosion-material-process guidelines for corrosion or process engineers.

Polythionic Acid Stress Corrosion Cracking

Mon, 01 Jan 0001 00:00:00 +0000

General Information

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.¹ ² Therefore, PTASCC occurs commonly in areas typically operating in range of 370-843°C (700-1550°F) where sensitization of austenitic materials will progress.² ³ ⁴

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.

Wet H2S Damage (Blistering/HIC/SOHIC/SSC)

Mon, 01 Jan 0001 00:00:00 +0000

General Information

Mechanism

Key Variables

Temperature

Species

Metallic materials impacted by Wet H2S Damage (Blistering/HIC/SOHIC/SSC)

Flow regime

Calculation Tools

The intention of these tools is to provide quick corrosion-material-process guidelines for corrosion or process engineers.