Data Analysis of Large Hexagonal Steel Structural Bolts and Torsional Shear Bolts
Data Analysis of Large Hexagonal Steel Structural Bolts and Torsional Shear Bolts
Data Analysis of Large Hexagonal Steel Structural Bolts and Torsional Shear Bolts
The bolt connection pair of the large hexagonal steel structure has two sealing rings, one on each side of the bolt head and nut; Twist shear high-strength bolts only have one sealing ring and one on the nut side. The high-strength bolts with large hexagonal heads are divided into Grade 8.8 and Grade 10.9, while the high-strength bolts with torsion shear type are only Grade 10.9. Large hexagonal steel structural bolts use torque wrenches; The torsion shear type high-strength bolt adopts an electric wrench, and the box head can be twisted and broken.
During the entire construction process, the final tightening torque control of the large hexagon is not very good, and the average altitude is unfavorable for tightening and inspection. However, the excellent practical operation of the torsion shear type is generally estimated. The spacing between torsion shear high-strength bolts exceeds the spacing between large hexagonal steel structural bolts. When the portal steel structure adopts blue plate connection, the usage of torsional shear channel steel is 1-5% higher than that of large hexagonal head channel steel, and the price of large hexagonal head section steel is lower than that of torsional shear channel steel.
Steel structure portal steel frames generally use large hexagonal heads, and double-layer and multi-layer buildings generally use torsion shear type. In addition, there is also a type of electric wrench with a large hexagonal head, for example, the spacing between the large hexagonal head bolts of the electric wrench structure should be relatively increased. In some cases, when electric wrenches cannot be used for the construction of torsion shear bolts, large hexagonal steel structural bolts can be used. It can be inspected according to the corner method, and it is generally not easy to touch. Especially for some very large high-strength bolts, such as M33, M39, etc., this unique large bolt cannot be completed without scientific research and inspection in the usual way. Due to the large torque value of this type of bolt, it cannot be completed with a torque wrench. At this point, the perspective method can be used, but the prerequisite is to conduct key experiments at the manufacturer of high-strength bolts. The common specifications and models of torsion shear high-strength bolts include M16, M20, M22, and M24. The construction quality is very easy to ensure, but the quality of electric wrenches used in domestic engineering construction is poor, and the price of imported single machine versions is too high.
In addition, because the price of torsional shear bolts is too high for large hexagonal structural bolts, most of the large hexagonal structural bolts are used for the construction of single-sided steel structural engineering. Throughout the entire construction process, it is essential to regularly inspect and calibrate torque wrenches. If it is not possible to retest the torque index of large hexagonal steel structural bolts on site in the engineering project, it is proposed to use torsion shear high-strength bolts as much as possible to ensure construction quality. In addition, on-site engineering supervision personnel must conduct inspections on the electric torque wrenches they use to prevent some installation teams from adopting extreme measures without commonly used tools, which may lead to potential safety hazards in construction quality.
