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From cryogenic to +700C service, bolts face brittle fracture, relaxation, and creep. Learn material selection by temperature zone per GB/T 3098.8-2010.

Following GB/T 3098.25-2020, map corrosive media, temperature, and concentration to stainless and nickel-alloy grades, with key criteria and material-selec

Stainless fasteners are not maintenance-free. Learn the GB/T 3098.6 class system, the A2/A4 composition and boundaries, and when chloride environments requ

Hardness testing is fast and non-destructive but is not a substitute for strength testing. Learn the limits of GB/T 1172 conversion and when to use Brinell

Proof load and minimum tensile load are often confused; one guards against permanent deformation and the other against fracture. Learn which indicator appl

How to choose between property classes 8.8, 10.9, and 12.9 based on tensile strength, toughness, hydrogen embrittlement sensitivity, cost, and operating co

A GB/T 3098.1 report with all-pass numbers does not mean the bolt is safe. This article breaks the standard into strength, ductility, and functional indica

From design to retirement, a bolt goes through preloading, loading, relaxation, and fatigue. This article traces the bolt's load evolution across four stag

Most bolt fractures are fatigue, not static strength. This article covers the stress-amplitude criterion, the notch factor at the thread root, Goodman mean

How long should thread engagement be? This article explains the exponential load decay across thread flanks, the material strength ratio table from steel-s