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China Black Zinc Oxide CSK Flat Head Hexagonal Bolt Screw Supplier - Factory Direct Pricing and High Quality
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
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Mechanical Manufacturing Used for the assembly of precision equipment (such as machine tools and molds), in areas that require high loads and limited space.
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Automotive Industry Requires highly reliable connections for engine components, transmissions, chassis, and other components.
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Electronic Products The structural fixation of compact devices such as laptops and mobile phones.
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Aerospace Connection points with high requirements for weight and strength in lightweight design.
Core Advantages
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High Torque Transmission
The contact area between the hexagonal hole and the wrench is large, which can withstand greater tightening torque.
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Space Saving
The flat head design does not occupy external space, making it suitable for small or aesthetically pleasing installation environments.
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Anti-Loosening Performance
When used in conjunction with spring washers or thread glue, it can effectively prevent loosening caused by vibration.
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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)
Q 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 surface that sits flush with or below the workpiece surface after installation, eliminating protrusions. A regular (cylindrical head) socket cap screw has a raised head that sits above the surface. Flat head versions are preferred where a smooth, streamlined finish is required.
Q 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 a combination of lightweight properties and high strength.
Q What size range is available for flat head socket cap screws?
Standard metric sizes typically range from M2 to M24, following ISO 4762 specifications. American standard sizes follow ANSI/ASME B18.3. Custom lengths and diameters can also be manufactured to meet specific application requirements.
Q How can I prevent flat head socket cap screws from loosening over time?
To prevent loosening caused by vibration or dynamic loads, flat head socket cap screws can be used in combination with spring washers, lock washers, or thread-locking adhesives such as Loctite. Proper torque application during installation is also essential to maintain a secure connection.
Q What surface treatments are available, and which should I choose?
Common surface treatments include galvanizing for general rust protection, Dacromet coating for high-temperature and corrosion-resistant environments, and electrophoretic coating for decorative or aesthetic applications. The choice depends on the operating environment, temperature conditions, and appearance requirements of your application.
Q Are flat head socket cap screws suitable for aerospace and automotive applications?
Yes. Flat head socket cap screws are widely used in aerospace for lightweight, high-strength connections, and in the automotive industry for critical components such as engines, transmissions, and chassis. Their high torque transmission capability, flush installation profile, and availability in titanium and stainless steel make them ideal for demanding, safety-critical environments.