The study of the susceptibility to hydrogen-stress cracking of heat-treated line-pipe steels has continued. Under experimental conditions that permitted stressed specimens to absorb hydrogen from only one plate surface (a condition that simulates a cathodically protected pipeline), the steels appeared to be less sensitive to hydrogen cracking than when hydrogen was absorbed on the entire periphery. Steels with yield strengths above 130 ksi were found to be susceptible to hydrogen cracking during cathodic charging in groundwater. Experiments are in progress in which pressurized bottles made of ...
The study of the susceptibility to hydrogen-stress cracking of heat-treated line-pipe steels has continued. Under experimental conditions that permitted stressed specimens to absorb hydrogen from only one plate surface (a condition that simulates a cathodically protected pipeline), the steels appeared to be less sensitive to hydrogen cracking than when hydrogen was absorbed on the entire periphery. Steels with yield strengths above 130 ksi were found to be susceptible to hydrogen cracking during cathodic charging in groundwater. Experiments are in progress in which pressurized bottles made of pipe steel, heat-treated to high strength levels, are buried in the field and cathodically protected. These experiments will show whether hydrogen-stress cracking will occur under actual pipeline operating conditions, and if so, at what strength level suck cracking becomes a problem. A probe legs developed that will aid in studying the influence of soil chemistry and cathodic-protection conditions on the rate at which hydrogen is absorbed by steel.