What is a common damage mechanism in equipment exposed to wet hydrogen sulfide environments?

In equipment exposed to wet hydrogen sulfide (H2S) environments, cracking in the welds and heat affected zones is a common damage mechanism due to the specific properties of H2S. This substance is known to promote stress corrosion cracking, particularly in steels that have been welded.

When materials are subjected to both corrosive environments and mechanical stresses, the welds and the heat affected zones can become susceptible to cracking. This occurs because the heat from welding alters the microstructure of the metal, creating areas that are more vulnerable to the effects of H2S. The presence of moisture, combined with the specific conditions created by H2S, exacerbates the potential for these cracks to form, effectively leading to premature failure of the pressure vessel.

Understanding how wet H2S affects welds and the surrounding metal is critical for ensuring the integrity of pressure vessels in such environments. Regular inspection and monitoring of these areas can help in identifying potential issues before they lead to catastrophic failures. Other damage mechanisms like general pitting or hydrogen embrittlement may occur in these environments but are not as directly related to the vulnerabilities associated with welded joints specifically.