Hydrogen Embrittlement of Valve Capscrew Fasteners

Body capscrews from a ball valve showing hydrogen embrittlement fracture. Exposed to atmospheric conditions in a gulf coast environment, they corroded and fractured, separating the valve body. The left capscrew fractured due to hydrogen embrittlement cracking through the complete cross section. The right capscrew initially fractured due to hydrogen embrittlement then propagated due to tensile overload. Both fractures started at the bottom of the photograph.