API 571 Certification (Corrosion & Materials) Practice Test

Which of the following is a characteristic of wet H2S cracking?

1. It primarily affects stainless steels

2. It only impacts non-ferrous alloys

3. It affects carbon steels and martensitic SS

4. It is not temperature dependent

The correct answer is: It affects carbon steels and martensitic SS

Wet hydrogen sulfide (H2S) cracking, also known as sulfide stress cracking, is a type of hydrogen-induced cracking that predominantly affects carbon steels and martensitic stainless steels. This form of cracking is particularly relevant in environments where H2S is present, such as in oil and gas production and refining processes. The susceptibility of carbon steels and martensitic stainless steels to wet H2S cracking is due to their microstructure and the presence of specific mechanical properties that make them vulnerable to cracking in the presence of H2S. The occurrence of this type of cracking is influenced by various factors, including the concentration of hydrogen sulfide, temperature, and the mechanical stress state of the material. Carbon steels, being prevalent in many industrial applications, and martensitic stainless steels, which can have increased hardness and strength, are thus of primary concern regarding damage from wet H2S environments. In contrast, stainless steels in general are often more resistant to corrosion and cracking due to their alloying elements, which enhance their resistance to such conditions, making the first option inaccurate. The choice indicating only non-ferrous alloys being affected is not correct because wet H2S cracking does not typically target these materials and primarily involves carbon steels and martensitic