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China Black Zinc Oxide CSK Flat Head Hexagonal Bolt Screw - Suppliers & Factory for High-Quality Fasteners
Structure and Characteristics
🔩 Head Design
Flat Head: The top surface of the head is flat and can be aligned with the surface of the workpiece after installation, reducing protrusions and suitable for occasions that require a flat or streamlined appearance.
📐 Conical Bottom Surface
The bottom surface of the head is usually conical and can be embedded into the pre-made conical counterbore of the workpiece to provide better fit.
🔧 Hexagonal Drive
The hexagonal groove in the center of the head (ISO 4762 standard) can fully fit with the internal hexagonal wrench, transmitting large torque and reducing the risk of slipping.
⚙️ Threaded Section
The thread types are mostly metric coarse teeth (such as M4, M6) or fine teeth (such as M8 × 1.25), and the length and diameter can be customized according to needs.
Main Application Scenarios
🏭
Mechanical Manufacturing
Used for the assembly of precision equipment (such as machine tools and molds), in areas that require high loads and limited space.
🚗
Automotive Industry
Requires highly reliable connections for engine components, transmissions, chassis, and other components.
💻
Electronic Products
The structural fixation of compact devices such as laptops and mobile phones.
✈️
Aerospace
Connection points with high requirements for weight and strength in lightweight design.
Core Advantages
💪
High Torque Transmission
The contact area between the hexagonal hole and the wrench is large, which can withstand greater tightening torque.
📦
Space Saving
The flat head design does not occupy external space, making it suitable for small or aesthetically pleasing installation environments.
🔒
Anti-Loosening Performance
When used in conjunction with spring washers or thread glue, it can effectively prevent loosening caused by vibration.
✨
Aesthetics
After installation, the surface is flat without exposed bolt heads, suitable for products with high appearance requirements.
Specifications and Standards
| Category | Details |
|---|---|
| Material | Carbon steel (surface galvanized, blackened treatment), stainless steel (such as 304/316, corrosion-resistant), titanium alloy (lightweight and high-strength scenario). |
| Size Standard | Metric (ISO 4762), American (ANSI/ASME B18.3), with a common diameter range of M2 to M24. |
| Surface Treatment | Galvanized (rust proof), Dacromet (high-temperature corrosion resistance), electrophoretic (decorative coating), etc. |
Frequently Asked Questions (FAQ)
❓ What is the difference between a flat head socket cap screw and a regular socket cap screw?
A flat head socket cap screw features a countersunk, flat-top head that sits flush with or below the workpiece surface after installation, whereas a regular socket cap screw has a cylindrical raised head that protrudes above the surface. The flat head design is preferred when a smooth, streamlined finish is required.
❓ What materials are flat head socket cap screws available in?
They are commonly available in carbon steel (with galvanized or blackened surface treatment), stainless steel grades 304 and 316 for corrosion resistance, and titanium alloy for applications requiring both lightweight properties and high strength.
❓ What size range do flat head socket cap screws come in?
Standard flat head socket cap screws are available in metric sizes ranging from M2 to M24, following ISO 4762 standards, as well as American standard sizes per ANSI/ASME B18.3. Custom lengths and diameters can also be manufactured upon request.
❓ How do I prevent flat head socket cap screws from loosening under vibration?
To prevent loosening caused by vibration, it is recommended to use flat head socket cap screws in combination with spring washers or apply thread-locking adhesive (such as Loctite) to the threaded section. These methods significantly improve anti-loosening performance in dynamic environments.
❓ Which surface treatment is best for outdoor or corrosive environments?
For outdoor or corrosive environments, stainless steel (304/316) screws or carbon steel screws with Dacromet coating are recommended. Dacromet provides excellent resistance to high-temperature corrosion, while 316 stainless steel is particularly suitable for marine or chemical environments.
❓ Can flat head socket cap screws be used in aerospace applications?
Yes. Flat head socket cap screws made from titanium alloy or high-grade stainless steel are widely used in aerospace applications where lightweight design, high strength, and reliable connection performance are critical requirements. They meet stringent aerospace standards for both weight reduction and structural integrity.