Low Alloy Steels in Hydrogen Sulfide Environment

The effect of chemical composition on the behavior of low alloy steels in a hydrogen sulfide environment was studied with regard to corrosion, hydrogen absorption, and sulfide stress cracking. Results were interpreted in connection with microstructure and carbide precipitation. The addition of chromium results in the promotion of hydrogen absorption presumably due to the precipitation of incoherent carbides, thereby reducing, in general, the resistance to SSC. Fine coherent carbides appear to be beneficial, or at least not detrimental, to SSC resistance; e.g., Mo₂C, VC, TiC, and NbC. Microstructure seems to affect both hydrogen absorption and SSC resistance largely through the trapping behavior of hydrogen at the carbide/matrix interface.