Carbon steels hydrogen damage

A six-inch carbon steel elbow in a Los Angeles refinery ruptured releasing a hydrocar-bon/hydrogen mixture at 9 43 P.M. on October 8, 1992. The vapor cloud ignited within seconds. The explosion damaged nearby buildings and shattered windows several miles away and was recorded as a sonic boom at the California Institute of Technology about 20 miles away. [21]... 

The body-centered crystal structures of carbon and low-alloy steels are susceptible to four types of hydrogen damage, two of which are low-temperature processes and two are high-temperature processes ... 

Fig. 14. 38 Micrograph of the intergranular attack in a carbon steel pipe type A 106 severely damaged by hydrogen embrittlement [72]...

Particularly common in the oil and gas industry, where the use of steel pressure vessels is widespread, the risks of HlC should be considered when hydrogen snlfide partial pressure becomes greater than 3.5 mbar. Carbon steel pressure vessels should not be affected by HlC damage where HjS levels are lower than this figme in a normal service life cycle. HlC is prevalent in wet HjS environments, which is often known as sour service such cracking over a prolonged period of time without inspection will reach a critical point and the steel component, i.e. pressure vessel, could easily fail. 

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