Optimization of rivet riveting parameters for saw-chain and their effects on fatigue performance

To resolve the issues of insufficient uniformity and tightness in the riveting process of the saw-chain rivet, this study proposes an optimization method to improve the riveting quality of the chain links, and systematically investigates the underlying relationship between riveting quality and fatigue performance of the system. By constructing a mapping model between three key factors in the orthogonal experimental design and the riveting upsetting displacement, the nodal coordinates of the inner surface of the side-link hole were extracted using the finite element analysis method. Combined with point cloud analysis and the convex hull algorithm, a computational methodology for quantifying the interference volume during riveting was developed. Based on the residual stress analysis, the optimized dimensional scheme was determined. Finally, the effect of interference-fit quality on fatigue performance was validated through linear fatigue tests and wire-EDM morphology analysis. Result shows that the interference volume between the rivet and the side link increased by 24.28% following optimization, while the average fatigue load cycles of the specimens rose from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mn>3</mml:mn> <mml:mo>.</mml:mo> <mml:mn>59</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>4</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mn>3</mml:mn> <mml:mo>.</mml:mo> <mml:mn>90</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>4</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> , the dispersion of fatigue load cycle is reduced, and the stability is improved. Moreover, wire-cut cross-sectional observations revealed that the optimized specimens exhibited a more continuous and smoother riveted interface, indicating enhanced structural integrity of the riveted region. These findings confirm that the proposed parameter optimization effectively improves riveting quality and contributes to extended service life of saw-chain systems.