Detachable bolt connection is a reliable method of fastening structural parts with the possibility of quick dismantling in the future.
Structural fastening: high-strength bolts, nuts and washers
Ease of assembly and disassembly of products connected by high-strength structural fasteners is ensured by the use of bolts, nuts and washers of the required strength class. It is simplicity and versatility that allowed high-strength structural fastening to find its application in a wide range of fastening of massive metal, wooden and other parts.
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Structural fastening with the use of high-strength bolts, nuts and washers is used in railway construction, in the construction of bridges, in machine building, industrial production, in the construction of high-rise metal objects for sports, economic and industrial purposes, etc. Taking into account the gradation of threaded fasteners by strength classes, high-strength structural fasteners in various standardization systems include connections using high-strength bolts of class 8.8, 10.9 and more, the tensile strength of which is not lower than 800 N/mm² (the value for bolts is indicated class 8.8). |
Structural fastening using high-strength bolts of class 10.9 with a strength limit of 10 (the first number of the class marking) × 100 = 1000 N/mm² and a yield strength of 10 (the first number) × 9 (the second number) × 10 = 900 N/mm² is the most universal. It can be used in responsible structures for highly loaded, prestressed connections. It is also important that, in addition to direct use, according to the project documentation, high-strength bolts of a lower class (8.8) can be replaced with this metal product.
Use of high-strength structural fasteners
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High-strength structural fastening requires the use of a high-strength bolt (eg DIN 6914 or EN 14399) complete with зhigh-strength nut (DIN 6915, EN 14399) and two high-strength washers (DIN 6916, EN 14399). One high-strength washer should be placed on the side of the bolt, the other on the side of the nut. The use of a complete set of structural fasteners (a high-strength bolt, a nut and two washers) makes it possible to increase the stability of the connection: strength will be achieved due to the friction force between the connecting planes. In order for the structural fastening to meet the stated requirement for strength, the connection must accept forces not on shear (bolt shear), but on surface friction. For this, you should ensure reliable tightening of the bolts and pre-prepare the planes of the surfaces connected by structural fasteners. |
Increased tension of the bolts of high-strength structural fasteners is provided by special torque wrenches that make it possible to control the tightening moment and determine the reliability of the connection. Surfaces of structural fastening, as well as high-strength bolts, nuts and washers themselves, require cleaning from dirt, rust and a preliminary check of integrity.
High-strength bolts, nuts and washers for structural connections
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The set of structural fasteners can include:
Structural fasteners of the DIN 6914-6916 (EN 14399) standard are made of low-carbon alloy steel. Metal products have hexagonal heads of increased size on a turnkey basis. |
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