Sulfide Stress Cracking
Sulfide Stress Cracking is also known as SSC, Hydrogen Embrittlement or acid brittleness. It is a spontaneous brittle failure of high strength allow or steel in presence of humid hydrogen sulfide. When susceptible alloys or steel comes in contact with Hydrogen Sulfide, the chemical reaction makes metal sulfide and releases atomic hydrogen. Atomic hydrogen can combine to result in H2 which disperses into metal matrix taking up more space and weakening the bonds between the grains of metal. Formation of molecular hydrogen causes sudden failure due to cracking under tensile stress. This failure is generally limited to steels or alloys having a hardness of 22 or greater on the Rockwell C scale.