Factors affecting the torque coefficient and tightening axial force of high-strength fasteners for steel structures

There are many factors that affect the torque coefficient and tightening axial force of high-strength fasteners for steel structures. When the inherent quality of high-strength fasteners (that is, the strength of the product) is constant, the main factors that affect the torque coefficient and tightening axial force of high-strength fasteners The factors are: the surface treatment state of the connection pair, such as oxidation treatment, phosphate saponification treatment, etc. (good treatment, high lubrication quality, and its tightening axial force is large); the torsion shear groove diameter of the torsion shear bolt (torsion shear groove) The larger the diameter, the greater the tightening shaft force, which is determined after design calculations and process tests); (Guide: How to remove worn hexagon socket bolts)

The friction state between the bearing area of u200bu200bthe bolt (the support surface under the head), the support area of u200bu200bthe nut and the support area of u200bu200bthe washer (the friction between each other is large, the tightening axial force is small, and the tightening axial force is large) ; The surface friction state between the bolt and nut thread (the friction between each other is large, the tightening axial force is small, and the tightening axial force is large); the product's geometric dimensional accuracy and surface quality (requires uniform geometric dimensional accuracy, The surface of the product is smooth and no bumps); packaging, storage and sealing state (no sand, dust, dryness does not change) and so on.

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