Ni Restriction in Sour Service
Nickel (Ni) is restricted to a maximum of 1% in sour service due to its tendency to form brittle intermetallics with other metals in the presence of hydrogen sulfide (H2S). This phenomenon is particularly concerning in sour service applications, where H2S is present in high concentrations and can cause corrosion and degradation of the metal.
The formation of brittle intermetallics can reduce the toughness and ductility of the metal, making it more susceptible to cracking and failure. In addition, the presence of Ni in high concentrations can also increase the susceptibility of the metal to corrosion in sour service environments.
Therefore, to ensure the reliability and safety of equipment used in sour service applications, regulations and industry standards often limit the amount of Ni in the materials used for these applications. This helps to minimize the risk of failure and ensure the safe operation of equipment in harsh sour service environments.
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