Investigation of Grain Boundary Chemical Composition in Martensitic Class Low-Carbon Steels After Prolonged Tempering

Nickel concentration at grain boundaries is studied in martensitic steels by Auger electron spectroscopic analysis after various heat treatment operations. Absence of a directly proportional relationship between nickel content within grain boundaries and impurity element concentration in these boundaries after quenching and long-term high-temperature tempering is established. The role of nickel in transformations occurring during high-temperature tempering in steels is demonstrated on the basis of existing ideas about the mechanism and driving forces for these transformations.