ZHENG Renren, XIE Jinli, SHI Songyi, XIE Mingzhao, SUN Zhimin, QIN Hailong
Superalloy ring components are crucial load-bearing components in aerospace, and residual stress is one of the key factors influencing their processing deformation and service life. Contour method enables comprehensive characterization of internal residual stress distribution, providing core data support for stress regulation, deformation mitigation, and service reliability improvement. This study focused on such superalloy ring components, employing contour method to investigate their residual stress evolution before and after heat treatment. To address the low efficiency of contact coordinate measuring machine (CMM) in contour method testing, the influence of non-contact optical scanning (NCOS) on residual stress testing of superalloy ring components by contour method testing was explored. The results showed that the residual stress of initial state sample was distributed in an outward tensile and inward compressive pattern. The maximum tensile stress was 658 MPa and the maximum compressive stress was 247 MPa, with a relatively large stress gradient. During heat treatment, residual stress evolved in two stages. During the heating stage, the initial stress gradually released as the material strength decreased. During the cooling stage, due to the difference in cooling rates at the edges and the core, an external pressure and internal tension distribution was formed. The maximum tensile stress dropped to 76 MPa, and the compressive stress was 204 MPa. The stress values and gradients had significantly decreased. NCOS and CMM yielded consistent stress distribution patterns, but the test values of NCOS were affected by the stress gradient. When the stress gradient was large, the measured value was smaller; when the stress gradient was small, the measured value was larger. This study clarified the residual stress evolution law of such components, providing a basis for heat treatment process optimization, and verified that NCOS was suitable for residual stress testing of superalloy ring components, with attention to the impact of NCOS data smoothing on test results.
