Decarburization, grain boundary segregation of P and primary water stress corrosion cracking in a low-alloy steel

Decarburization causes intergranular brittleness of a low-alloy steel, arising from P segregation at grain boundaries. The grain boundary segregation concentration of P increases with decreasing decarburization temperature and increasing holding time at a temperature, resulting in the drastic decrease in intergranular fracture strength. It was confirmed that surface oxide films formed along the grain boundaries during decarburization act as a prerequisite factor for intergranular stress corrosion cracking of the low-alloy steel in a primary water environment.