Stress corrosion cracking behavior of quenched and tempered 2.25Cr 1Mo steel

For stress corrosion cracking (SCC) study of 2.25Cr-1Mo steel, speciemens were initially austenitized at 925 degree C for 2 hours and quenched in ice brine solution. With this process of heat treatment martensite was formed and banded morphology in the microstructure developed during previous processing was also removed. Tempering at 575 Degree C for 1h was employed to introduce ductility in the quenched martensite of the specimens. The effects of temperature variations on SCC behavior showed a successive decrease in strength and ductility of the steel. These variations in tensile properties were correlated with scanning electron microscopic (SEM) examinations. The SEM results clearly revealed that mostly transgranular cracks initiated at the edges of the tensile specimens grown perpendicular to loading axes, and their intensity is increased with the testing temperatures. (author)