GB/T 32076.3-2015 High-strength structural bolting assemblies for preloading—Part 3:System HR—Hexagon bolt with large width across flats and nut assemblies

Scope

This part of GB/T 32076 and GB/T 32076.1 specifies high-strength bolt and nut assemblies with thread sizes from M12 to M36, a large hexagonal series, performance grades of 8.8/8 and 10.9/10, HR type, and preloaded connections. The bolts and nut assemblies designed in this part allow a preload of ≥0.7Rm×A1)s, and the extension performance is primarily ensured by the plastic elongation of the bolts. For this reason, the parts should have the following characteristics: -- Type 1 (standard) nut height, as specified in GB/T 6170; -- The thread length of the bolts should comply with GB/T 3106. The bolt and nut assemblies specified in this part should also include washers according to GB/T 32076.5 (only under the nut support surface) or/and GB/T 32076.6. Note: To obtain satisfactory results, ensuring the correct use of bolts is very important. For methods of correct use, please consult or refer to relevant standards. Preload adaptability tests are described in GB/T 32076.2. This part applies to high-strength bolt and nut assemblies used for preloaded connections in industrial and civil buildings, bridges, tower structures, boiler steel structures, lifting machinery, and other steel structures. Appendix A provides the total clamping length and clamping length of bolt and nut assemblies. Appendix B provides explanations of two application types of bolt and nut assemblies in European steel structures. 1) Rm is the nominal tensile strength, and As is the nominal stress area of the thread.

Development Information

Same series standard

Referenced Standards

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