Release time：2020-01-16 18:44 Browse：
### 1. **Core Specifications** - **Size Details**: 4.8×1.6, typically indicating a shank diameter of 4.8mm and a length of 16mm (common metric notation for screws, where "1.6" may refer to length in mm). Thread pitch follows standard metric coarse threading (e.g., 0.8mm for M4.8), optimized for self-tapping performance. - **Type Classification**: Hexagonal flange head hex flange tapping screw, a specialized fastener combining the drive convenience of a hexagonal head with the load-distributing benefit of an integrated flange. ### 2. **Head & Thread Engineering** - **Hexagonal Flange Head**: - The hexagonal (hex) drive allows for high torque application using standard hex wrenches or socket tools, reducing slippage during installation. - Integral flange (a circular rim extending from the head base) increases the bearing surface area by 30–50% compared to non-flange screws, preventing damage to soft materials (e.g., plastic, thin metal) and minimizing pull-through under vibration. - Flange edges may feature subtle serrations (depending on design) to enhance grip on mating surfaces, improving anti-loosening performance. - **Tapping Thread Design**: - Self-tapping threads with a sharp, tapered tip that cuts and forms threads in pre-drilled pilot holes (or even directly in thin materials), eliminating the need for pre-tapped holes. - Thread profile is engineered to balance cutting efficiency and thread strength, ensuring secure engagement in materials like aluminum, mild steel, or ABS plastic. ### 3. **Surface Treatment: White-Blue Galvanization** - **Process**: Achieved through electroplating a zinc layer (5–10μm thickness) followed by a white-blue chromate conversion coating, creating a protective barrier against corrosion. - **Benefits**: - Corrosion resistance: Withstands ≥48 hours in salt spray testing (per ASTM B117), suitable for humid or lightly exposed environments (e.g., indoor machinery, outdoor fixtures with minimal weathering). - Aesthetic finish: Bright white-blue appearance enhances visual appeal, making it ideal for visible applications (e.g., furniture, consumer electronics). - Lubricity: The chromate layer reduces friction during installation, preventing thread galling in soft metals. ### 4. **Material & Mechanical Properties** - **Base Material**: Carbon steel (e.g., SWRCH18A or equivalent), chosen for its balance of machinability and strength. - **Strength Grade**: 4.8, indicating: - Tensile strength: ≥400 MPa - Yield strength: ≥320 MPa - Hardness: 100–150 HV (Vickers), ensuring the screw can withstand typical tightening forces without breaking or deforming. ### 5. **Application Scenarios** - **Primary Uses**: - Fastening thin metal sheets (e.g., 0.5–2mm steel/aluminum) in electrical enclosures, HVAC panels, or automotive trim. - Securing plastic components (e.g., ABS, polypropylene) in consumer goods, such as appliance housings or furniture hardware. - Light-duty structural connections where pre-tapped holes are impractical, thanks to the self-tapping design. - **Environmental Suitability**: Best for indoor or sheltered outdoor environments; avoid prolonged exposure to saltwater or heavy industrial chemicals (upgrade to stainless steel for harsher conditions). ### 6. **Installation & Handling** - **Pilot Hole Requirement**: For harder materials (e.g., 1mm+ steel), a pilot hole (3.5–4.0mm diameter for M4.8) is recommended to reduce installation torque and prevent thread stripping. - **Tool Compatibility**: Works with standard hex tools (e.g., 5mm or 6mm hex sockets, depending on head size), enabling manual or automated (power drill) installation. - **Storage**: Store in dry, ventilated areas to preserve the white-blue galvanized coating; avoid contact with abrasive materials that may scratch the surface. ### 7. **Quality & Compliance** - Manufactured to international standards (e.g., ISO 14583 for hex flange tapping screws) to ensure dimensional consistency. - Undergoes quality checks including thread gauge verification, coating thickness measurement (via X-ray fluorescence), and torque-to-failure testing for batch reliability.
