Pipeline steel susceptibility

Similar to hydrogen gas vessels, the hydrogen embrittlement susceptibility of pipeline steels depends on gas pressure. Industrial gas companies have operated steel hydrogen pipelines at gas pressures up to 13 MPa. ... 

Embrittlement of service materials. The low temperatures inside storage tanks and transmission pipelines may cause significant susceptibleness of the structural material in vibrations and shocks. Mild steel and most iron alloys, at LH2 temperatures, lose their ductility being liable to increased risk of mechanical failure [50]. 

Most fuel system storage tanks, transfer lines, and underground pipelines are composed of 1018/1020 carbon steel. These system components are all susceptible to internal corrosion whenever fuel containing water is introduced. Other factors which can enhance fuel storage and transportation system corrosion include ... 

Although low values of CE are specified to prevent martensite formation in welds [31], these regions are often still harder than the surrounding pipeline base metal. As documented in Section 3.4.1, higher hardness (i.e. higher yield strength) makes steel welds more susceptible to hydrogen embrittlement. 

It is important to control the surface area of manganese sulfide inclusions. During the rolling process for pipeline manufacture, for example, these inclusions get flattened to form platelets. This ino-eases the available surface area for hydrogen adsorption and therefore increases material susceptibility to HIC. One way to control this is the addition of calcium to ladle steel. Calcium reduces the oxygen and sulfur content of the steel. Calcium also results in the spheroidization of sulfide inclusions, thereby decreasing the available surface area for adsorption of atomic hydrogen. 

An acceptable life for undergound pipelines can sometimes be realized through the use of corrosion-resistant piping. Copper, aluminum, and stainless steel piping are sometimes used for this purpose. All three alloys can have greater corrosion resistance than carbon steel or cast iron. However, they are not immune to corrosion and are often more susceptible to localized corrosion such as pitting, crevice corrosion, and SCC than carbon steel or cast iron. Further, corrosion protection in the form of coatings and cathodic protection are frequently used. 

As a result of their increased flexibihty floating reinforced rubber pipelines are generally more able to resist swell, waves and movements of the dredger than steel pipelines. As it is placed on the seabed a sinker line is not or only minimally susceptible to sea conditions, but the installation of such a pipeline in adverse conditions could be very difficult. 

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