Grade 10.9 Torque-Shear Bolts
Core Basic Parameters
**Specifications and Materials:** Common specifications range from M16 to M30, with lengths typically ranging from 40mm to 220mm. Materials used include alloy steels such as 20MnTiB and 35VB. M16-M24 specifications often use 20MnTiB, while M27-M30 specifications commonly use 35VB. These materials provide a foundation for the high strength performance of the bolts.
**Standards:** Must comply with GB/T3632-2008 standard. The bolt head will be marked with a performance grade of 10.9S, where "S" represents a high-strength bolt for steel structures, facilitating identification and quality traceability.
Connection Pair Composition: Each connection pair includes one bolt, one 10H-grade high-strength nut, and one HRC35-45 high-strength washer. All three components must be manufactured in the same batch to avoid batch variations affecting connection stability.
Key Performance Indicators
Excellent Mechanical Properties: As a high-strength bolt, its tensile strength is between 1040-1240 MPa, its yield strength is not less than 940 MPa, its elongation is not less than 10%, and its shrinkage rate reaches 42%. It can easily withstand dynamic loads and high preloads, exhibits strong fatigue resistance, and can effectively reduce the stress amplitude under dynamic loads, extending the service life of steel structures.
Flexible Corrosion Resistance: Various surface treatments are available. For conventional environments, blackening and phosphating are options, forming a protective film that balances rust prevention and friction coefficient stability. For special environments such as marine platforms and high-salt-spray environments, Dacromet coating or hot-dip galvanizing can be used. Dacromet coating, as an environmentally friendly zinc-aluminum based coating, exhibits particularly outstanding corrosion resistance.
Structural and Construction Advantages
Unique Structural Design: The bolt head is mushroom-shaped with a sprite-like tip at the end. This sprite-like tip is a key structural feature for construction and quality inspection. The underside of the head is treated with an anti-slip coating to prevent the bolt from slipping or spinning during installation, reducing safety issues caused by improper installation.
Convenient and Efficient Installation: Installation uses a dedicated torque wrench. The outer sleeve is fitted against the nut, and the inner sleeve is aligned with the sprite-like tip. Tightening is achieved through counter-force. When the torque reaches the standard value, the sprite-like tip will automatically break, indicating that the preload has reached 95-105% of the design value. This eliminates the need for manual torque measurement and avoids errors caused by friction coefficient fluctuations in traditional torque methods, making construction quality intuitive and controllable.
Main Application Areas
This bolt is a core component of steel structure connections and has a wide range of applications. In the construction field, it is suitable for core tubes of high-rise buildings, trusses of large-span stadiums, beam-column joints of factories, etc.; in bridge engineering, it can be used for main beam splicing, bridge deck connection and suspension bridge tower anchoring joints; in addition, it can also be used for heavy equipment such as tower cranes and wind turbine towers, as well as steel structure connections in special environments such as offshore platforms and transmission towers, and is compatible with various connection forms such as friction type and pressure type to meet different stress requirements.
