Pipeliners Dictionary
Hydrogen Induced Cracking (HIC)
Hydrogen-induced cracking (HIC) is a form of corrosion that can occur in pipelines and other equipment that transport sour gas or liquids containing hydrogen sulfide. HIC occurs when hydrogen sulfide diffuses into the pipeline material, causing hydrogen to penetrate into the material and form hydrogen blisters. Over time, these blisters can grow and cause cracking, leading to eventual failure of the pipeline.
HIC is a form of environmentally-assisted cracking, meaning that the cracking is caused by the interaction of the pipeline material with the environment. In the case of HIC, the environment is the sour gas or liquids containing hydrogen sulfide.
HIC is a concern for pipelines that transport sour gas, oil, and other liquids containing hydrogen sulfide, as the presence of this corrosive substance can increase the risk of HIC. The risk of HIC can be influenced by several factors, including the composition of the fluid being transported, the operating temperature and pressure, and the material properties of the pipeline.
To prevent HIC, pipeline designers and operators must consider several factors in the design and operation of the pipeline. These factors include:
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Material selection: The selection of the appropriate pipeline material can greatly impact the risk of HIC. Materials with low carbon content and low susceptibility to hydrogen embrittlement are generally preferred for pipelines that transport sour gas or liquids containing hydrogen sulfide.
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Operating conditions: The operating temperature and pressure of the pipeline can impact the risk of HIC. High temperatures and high fluid pressures can increase the risk of HIC, as they can cause hydrogen to diffuse more rapidly into the material.
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Corrosion protection: The use of appropriate corrosion protection measures, such as coatings, cathodic protection, and inhibitors, can help to reduce the risk of HIC.
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Inspection and maintenance: Regular inspection and maintenance of pipelines can help to detect and address any signs of HIC before they become a safety hazard.
In conclusion, hydrogen-induced cracking (HIC) is a form of corrosion that can occur in pipelines and other equipment that transport sour gas or liquids containing hydrogen sulfide. HIC is caused by the interaction of the pipeline material with the hydrogen-rich environment and can lead to eventual failure of the pipeline if not prevented. To prevent HIC, pipeline designers and operators must consider factors such as material selection, operating conditions, corrosion protection, and inspection and maintenance practices.
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