Release time：2020-01-16 18:44 Browse：
### 1. **Design and Structure Details** - **Extended Length Feature**: The "extended" design means the bolt’s shank (non-threaded or partially threaded portion) is longer than standard hex bolts, allowing it to penetrate through thick materials, multi-layered components, or deep-set holes—ideal for applications where a longer reach is needed (e.g., securing heavy machinery parts, structural brackets, or thick metal plates). - **Outer Hexagon Head**: A 6-sided external hex head with precise dimensions (e.g., head diameter, height) that aligns with metric standards. This design ensures compatibility with common wrenches, sockets, or power tools, enabling efficient, high-torque installation even in tight spaces. The flat or slightly rounded head top prevents snagging and ensures stable contact with the workpiece surface. ### 2. **Thread Specifications** - **Metric Thread Standards**: Manufactured to metric dimensions (e.g., M5 to M24 diameters, with thread pitches like 0.8mm, 1.25mm, 1.5mm) to fit global industrial standards (ISO, DIN, or GB). This ensures interchangeability in international manufacturing, construction, or repair work. - **Full vs. Half Thread Options**: - **Full threads**: The entire shank (from head to tip) is threaded, maximizing grip when paired with nuts or in fully tapped holes—ideal for applications requiring maximum clamping force (e.g., securing flanges or fixed joints). - **Half threads**: Only the lower portion of the shank is threaded, with the upper part remaining smooth. This balances grip with shank strength, making it suitable for heavy-duty use where the unthreaded section absorbs shear forces (e.g., in machinery with vibration or dynamic loads). ### 3. **Zinc Plating: Surface Treatment & Benefits** - **Electroplated Zinc Coating**: A thin layer of zinc is applied via electroplating, forming a protective barrier against corrosion. The plating thickness (typically 5–15μm) meets industry standards (e.g., ASTM B633) to resist rust, oxidation, and minor chemical exposure from moisture, humidity, or industrial residues. - **Aesthetic and Functional Finish**: The zinc plating often has a bright, silvery appearance, enhancing visual appeal in visible applications (e.g., furniture hardware, consumer appliances). It also reduces friction during installation, preventing thread galling (seizing) when tightened against nuts or tapped holes. ### 4. **Material and Mechanical Performance** - **Base Material**: Usually made from carbon steel (e.g., 4.8 or 8.8 grade) for cost-effectiveness and sufficient strength in general applications. Higher-grade options (e.g., 10.9 grade alloy steel) may be available for heavy-duty use, offering superior tensile strength (≥1000MPa) and resistance to deformation under high loads. - **Mechanical Properties**: Designed to withstand clamping forces, shear stress, and vibration. The extended shank’s thickness (matching metric diameter standards) ensures structural integrity, even when used in applications with repeated stress (e.g., automotive suspension parts, industrial conveyor systems). ### 5. **Applications Across Industries** - **Industrial Machinery**: Secures components in manufacturing equipment (presses, lathes, conveyors), where the extended length accommodates thick frames or multi-part assemblies, and the hex head allows reliable tightening. - **Construction and Structural Work**: Used in metal framing, steel structures, or concrete formwork, where the zinc plating resists outdoor elements, and full/half threads provide flexibility for different joint types. - **Automotive and Transportation**: Fastens undercarriage parts, engine components, or chassis brackets, leveraging the extended length to reach through layered metal and the hex head for easy maintenance. - **Consumer and Commercial Equipment**: Found in appliances (washing machines, generators), furniture, and tooling, where metric compatibility and corrosion resistance ensure long-term performance. ### 6. **Key Advantages** - **Versatility in Length and Threads**: The extended design and dual thread options (full/half) make it adaptable to diverse needs—from light-duty fastening to heavy-load applications. - **Corrosion Resistance**: Zinc plating extends service life in damp or moderately harsh environments, reducing replacement frequency and maintenance costs. - **Metric Compatibility**: Adherence to metric standards simplifies sourcing for global supply chains, ensuring it fits seamlessly with nuts, washers, and tapped holes in international markets. - **Reliable Installation**: The outer hex head’s design minimizes slippage during torque application, reducing the risk of stripped heads or uneven clamping—critical for safety in structural or high-vibration settings. ### 7. **Standards and Quality Assurance** - **Compliance**: Typically manufactured to ISO 4017 (general-purpose hex bolts) or DIN 931/933 (partially/fully threaded hex bolts) for dimensional consistency, ensuring that diameter, length, thread pitch, and head dimensions meet strict tolerances. - **Quality Checks**: Undergoes testing for thread accuracy (to ensure smooth engagement), plating adhesion (to prevent chipping), and tensile strength (to verify load-bearing capacity), ensuring reliability in end-use applications. ### 8. **Installation Considerations** - **Torque Recommendations**: Specific torque values depend on size and material (e.g., M10 8.8 grade bolts may require 35–50 Nm); using a torque wrench prevents over-tightening (which can strip threads) or under-tightening (which leads to loosening). - **Compatibility with Washers**: While not always necessary, pairing with flat washers can distribute clamping force and protect soft surfaces (e.g., wood, plastic) from indentation by the hex head. - **Environment Notes**: In highly corrosive settings (e.g., coastal areas, chemical plants), additional coatings (e.g., zinc-nickel plating) can be applied over the base zinc layer for enhanced protection.
