Hydrogen service, construction materials

Many users have reported satisfactory performance of annealed or normalized and tempered steels produced before 1969, as shown in Figure 1. These steels have been used for pressure-retaining equipment at design stress levels allowed by the 1969 or earlier editions of commonly-accepted codes (such codes include the ASME Code, Section Vlli, Division 1 the standards of the American National Standards Institute and, for the lower-strength materials, those of Deutsche Industrie-Normen). However, pressure vessels in hydrogen service have also been constructed using the higher allowable stresses permitted in either Section VHI, Division 2, or modifications of Section III of the ASME Code. Quenched and tempered or normalized and tempered steels have normally... 

Brittle Failure (8). Brittleness is a principal consideration in selecting construction materials for liquid hydrogen service. Brittle fracture can result in the essentially instantaneous release of a vessel s contents, the hazard being a combined one of PV energy release and the possibility of fire and/or explosion. Three conditions must exist for a brittle fracture to occur 1) a stress riser, a crack, notch, or other discontinuity, 2) a section where the actual stress exceeds the yield stress of the material, and 3) a temperature below which failure occurs without appreciable plastic deformation. Metals that are satisfactory for liquid hydrogen service include aluminum, stainless steels, brass, and copper. Carbon steel is not suitable. 

Carbon steel is the predominant construction material for carbonate and amine solution containers. Corrosion in the overhead lines (hydrogen sulfide or carbon dioxide plus water from the regenerator) is prevented by adding corrosion inhibitors. Although amine carry-over can act as a corrosion inhibitor in the overhead line, SCC of carbon steel has occurred when amine added as a corrosion inhibitor became concentrated. Copper and copper base alloys should be avoided in amine service and are questionable in carbonate seivice. Nickel or cobalt base alloys (e.g., Monel00 400 and Inconel 600) except for Stellite01 should be avoided in carbonate service. Monel 400 should be avoided in amine service if UCC Amine Guard02 corrosion inhibitor is used. 

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