Hebei Longze is a world-class manufacturer specializing in high-precision Tension Control (TC) Bolts, engineered to provide the most reliable fastening solutions for high-strength structural steel connections. Our Twist-Off Bolts are meticulously crafted in strict accordance with ASTM F1852, ASTM F2280, and EN 14399-10 standards, ensuring that every critical joint achieves the precise pre-load required for structural integrity without the need for tedious manual torque calibration.
Featuring an innovative spline end designed for use with specialized electric shear wrenches, these bolts offer a fail-safe installation process. Once the exact tension is reached, the spline automatically twists off, providing immediate visual verification of a correct installation. This advanced preloaded fastening system drastically reduces labor costs through single-operator installation while eliminating the engineering risks associated with over-tightening or under-tightening in heavy-duty construction.
Detailed Parameters
| Compliance Standards | ASTM F1852, ASTM F2280, EN 14399-10 | Material Grade | High-Tensile Alloy Steel (Grade 10.9, 10.9S) |
|---|---|---|---|
| Head Configuration | Round Head (Dome Head) with Spline End | Assembly Components | 1 Bolt + 1 Nut + 1 Hardened Washer |
| Metric Size Range | M16 - M36 | Imperial Size Range | 5/8" - 1-1/8" |
| Surface Treatment | HDG, Dacromet, Geomet, Black Oxide, Zinc | Primary Function | Preloaded Structural Fastening |
| Installation Tool | Specialized Electric Shear Wrench | Verification Method | Spline Twist-Off Visual Confirmation |
Key Advantages
Certified Strength
Strict adherence to ASTM and EN standards ensures maximum structural safety for high-load environments.
Rapid Installation
Single-operator installation significantly accelerates project timelines and reduces labor overhead.
Precision Tensioning
Eliminates manual torque errors, ensuring each bolt reaches the exact required pre-load every time.
Visual Confirmation
The "Twist-Off" mechanism provides instant ocular proof of correct installation for quality inspectors.
Extreme Corrosion Resistance
Available in HDG and Dacromet finishes to withstand harsh industrial and outdoor climates.
Versatile Application
Ideal for bridges, power plants, stadium roofs, and heavy-duty industrial framing.
Product Gallery
Management Platforms
Quality Control
Rigorous testing for tensile strength and hardness to meet ASTM/EN standards.
Precision Manufacturing
Advanced cold-heading and threading technology for exact spline dimensions.
Supply Chain Efficiency
Optimized logistics ensuring timely delivery for large-scale construction projects.
Coating Expertise
Specialized treatment lines for HDG and Dacromet anti-corrosion layers.
Inventory Management
Comprehensive stock of Metric and Imperial sizes for immediate dispatch.
Engineering Support
Technical guidance on pre-load calculations and shear wrench operation.
Investment Return Comparison
| Feature | Standard Heavy Hex Bolts | TC (Twist-Off) Bolts |
|---|---|---|
| Installation Speed | Slow (Manual Torque) | Ultra-Fast (Shear Wrench) |
| Labor Requirement | Two-man operation typical | Single-operator efficient |
| Accuracy Risk | High (Under/Over torque) | Near Zero (Auto-snap) |
| Inspection Time | Long (Torque testing) | Instant (Visual Check) |
| Overall Project Cost | Higher Labor Expenses | Reduced Total Installation Cost |
Frequently Asked Questions
ASTM F1852 is generally equivalent to A325 high-strength bolts, whereas ASTM F2280 is equivalent to A490, offering higher tensile strength for more demanding structural applications.
The bolt is designed with a spline end that shears off only when the specific tension is achieved, providing a mechanical guarantee of the correct pre-load.
For highly corrosive coastal environments, Hot Dip Galvanized (HDG) or Dacromet finishes are highly recommended due to their superior salt-spray resistance.
No, TC Bolts require a specialized electric shear wrench to grip the spline and ensure the "twist-off" occurs at the precise tension point.
We offer a comprehensive range from M16 to M36 in Metric sizes and 5/8" to 1-1/8" in Imperial sizes to suit various engineering specifications.
Yes, while primarily for heavy structures, their high strength and corrosion resistance make them excellent for large-scale photovoltaic ground-mount structural supports.
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