X-ray Residual Stress Analysis of Nitrided Low Alloyed Steels

AbstractResidual stress analyses were performed on nitrided, low alloy steels by varying the measuring conditions. The measurements were carried out in the compound layer on ∊-Fe2–3N and γ′-Fe4N as well as in the diffusion layer on α-Fe. By considering different criteria, tensile residual stresses of up to 300 MPa produced, {111}-interference, for ∊-Fe2–3N using CuKα radiation on the specimen's surface. After removing 5 μm from the surface, compressive residual stresses occur in this phase. On employing the CrKα and CuKα radiation, relatively high compressive stresses are obtained of up to above −1000 MPa for γ′-Fe4N. For measurements using CrKα radiation, compressive residual stresses result in the diffusion layer for α-Fe, which have a maximum value below the surface. Here, the measurements of the {211}-interference give lower residual stress magnitudes than measurements of the {110}- and {200}-interferences. By verifying the phase superpositions, the linear distributions of line positions or the compar...