Influence of Density and Distribution of Intergranular Sulfides on the Sulfide Stress Cracking Properties of High Strength Steels^★

The common occurrence of sulfide stress cracking failures of many steels in the intergranular mode suggests a need for a better understanding of the grain boundaries, particularly the boundary chemistry. The boundary chemistry of selected high strength steels is correlated to the minimum stress at failure in hydrogen sulfide solutions at room temperature. The technique of Auger electron spectroscopy (AES) in a scanning Auger microprobe was employed to study grain boundary composition and distribution of second phases at fresh fracture surfaces. The results indicate that S and Mn, precipitated in the form of a thin film of (Fe, Mn)S or P present at grain boundaries degrade the SSC properties of the material.