Release time：2020-01-16 18:44 Browse：
### 1. **Material & Strength: Carbon Steel ASTM 8 Grade**
- **Carbon Steel Base**: Fabricated from medium-carbon steel, chosen for its balance of strength, ductility, and cost-effectiveness. This material undergoes heat treatment (quenching and tempering) to meet ASTM 8 grade requirements, ensuring consistent mechanical properties across batches.
- **ASTM 8 Grade Specifications**: Conforms to ASTM standards for fastener strength, delivering a minimum tensile strength of approximately 800 MPa and yield strength of 640 MPa. This places it in the medium-high strength category, suitable for applications requiring reliable load-bearing capacity (e.g., securing machinery components or structural brackets).
### 2. **Design Features: Hexagon Flange Bolts & Nuts**
- **Integrated Hex Flange (Bolts)**: The bolts feature a hexagonal head with a built-in flange (a widened, flat collar beneath the head). This flange eliminates the need for a separate washer, distributing clamping force over a larger surface area to prevent damage to soft materials (e.g., plastic, thin metal) and reduce vibration-induced loosening.
- **Hexagonal Nuts**: Matching hex nuts are designed to pair with the bolts, featuring internal threads that precisely engage the bolt’s external threads for a secure, tight fit. The hexagonal shape allows easy torque application with standard wrenches or sockets.
- **Half-Threaded Configuration**: Both bolt sizes (3/8-18 X 1" and 5/16-20 X 1/2") have partial threading: the threaded section covers the lower portion of the shank, while the upper portion remains unthreaded. This design optimizes performance: the threaded part ensures strong engagement with the nut, while the unthreaded shank enhances shear resistance in dynamic or high-load environments.
### 3. **Size Details: 3/8-18 X 1" and 5/16-20 X 1/2"**
- **3/8-18 X 1"**:
- Thread diameter: 3/8 inch (9.525 mm)
- Thread pitch: 18 threads per inch (coarse thread, UNC)
- Overall length: 1 inch (25.4 mm), measured from the base of the flange to the tip.
- **5/16-20 X 1/2"**:
- Thread diameter: 5/16 inch (7.938 mm)
- Thread pitch: 20 threads per inch (coarse thread, UNC)
- Overall length: 1/2 inch (12.7 mm), measured from the base of the flange to the tip.
- These sizes cater to diverse assembly needs: the longer 3/8-18 X 1" suits thicker materials or multi-layer connections, while the compact 5/16-20 X 1/2" works for thin panels or tight spaces.
### 4. **Surface Finish: Black Oxide Treatment**
- **Process & Properties**: The bolts and nuts undergo black oxide finishing, a chemical treatment that converts the surface of the carbon steel into a thin, durable layer of black iron oxide (Fe₃O₄). This layer is typically 0.5-1.5 μm thick, providing:
- **Mild Corrosion Resistance**: When paired with a post-treatment (e.g., dipping in oil or wax), the oxide layer acts as a barrier against moisture and rust in dry or moderately humid environments.
- **Aesthetic Uniformity**: A sleek, matte black appearance that suits industrial or functional applications where visual consistency is desired.
- **Reduced Reflectivity**: Useful in environments where glare from metal surfaces could be problematic (e.g., machinery near sensors or in low-light settings).
### 5. **Applications & Use Cases**
- **Industrial Machinery**: Securing gears, pulleys, or frame components, where the flange’s load distribution and half-threads’ shear resistance prevent loosening under vibration.
- **Automotive & Equipment**: Assembling brackets, panels, or interior components, as the black oxide finish resists minor oil or fluid exposure, and the ASTM 8 grade strength handles engine or chassis-related loads.
- **Metal Fabrication**: Fastening structural steel, tubing, or sheet metal, where the compact hex design fits into tight spaces and the pre-integrated flange simplifies installation (no need for separate washers).
