This paper investigates manufacturing‑origin defects of M3‑M160 904L cold‑formed hex bolts for high‑volume fastener production. It focuses on under‑head laps, head cracks, eccentricity and incomplete fill introduced during multi‑station forming, which act as fatigue initiation sites under preload and cyclic bearing stress. A mechanism‑driven validation sequence, evidence matrix and engineering checklist are established. Nominal material and dimensional specifications cannot screen subsurface for

This paper investigates design issues of M3‑M160 904L stainless steel hex bolts applied to coastal and chloride‑exposed infrastructure. Focusing on crevice‑related field failures under sustained tension and vibration, thread load‑path characteristics are analysed. Five principal corrosion‑related failure mechanisms are identified, alongside mechanism‑driven validation workflow, evidence matrix and engineering checklist. Nominal 904L material cannot substitute joint‑level verification; all critic

This paper studies thread-root fatigue of M3–M160 904L stainless steel hex bolts applied to automotive brackets and chassis structures. Focusing on typical field failures where cracks initiate at the first engaged thread under road vibration, the load path of threaded connections is analysed. Five principal failure mechanisms are identified, and a mechanism-driven validation workflow, evidence matrix and engineering checklist are constructed. The study confirms that material designation and nomi

This article studies bolt preload retention of 904L stainless steel hex bolts (M3–M160) used for wind turbine support structures under cyclic wind loads. Starting from field joint failure cases involving settlement and interface opening, an elastic joint mechanical model is adopted to analyse load redistribution. Five core failure mechanisms are elaborated, including interface separation, thread fatigue, bolt head fillet bending, fretting loosening and concealed corrosion. A mechanism-based vali