Precautions for Grade 10.9 ISO 7380 Hexagon Socket Button Head Screws

1. Over‑load Use Prohibited: The head structure of ISO 7380 hexagon socket button head screws has limited load‑bearing capacity. Its actual ultimate tensile load is 80% of that of Grade 10.9 hexagon socket head cap screws of the same size. Selection must be based on special load parameters of ISO 7380. Using load standards for socket head cap screws as a substitute is strictly prohibited to prevent head fracture.

2. Prohibited for Transverse Shear Load Applications: ISO 7380 screws are only suitable for axial tension. The button‑head structure has extremely weak resistance to transverse shear. They are strictly forbidden to be used as pins or shear‑loaded fasteners to avoid shear fracture.

3. Prioritize Surface Treatments Free from Hydrogen Embrittlement Risk: For outdoor applications and critical safety scenarios, Dacromet/zinc‑aluminum coating or mechanical galvanizing shall be prioritized over electro‑galvanizing to fundamentally eliminate hydrogen embrittlement risk.

4. Carburizing/Nitriding Treatment Prohibited: Grade 10.9 ISO 7380 screws must undergo quenching and tempering heat treatment. Surface hardening processes such as carburizing and nitriding are strictly prohibited, as they will cause brittle fracture of screws.