Hot Products
0102030405
Black Zinc Oxide CSK Flat Head Hexagonal Bolt Screw - China Suppliers & Factory, Carbon Steel Alloy, ISO Certified
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
1
High Torque Transmission
The contact area between the hexagonal hole and the wrench is large, which can withstand greater tightening torque.
2
Space Saving
The flat head design does not occupy external space, making it suitable for small or aesthetically pleasing installation environments.
3
Anti-Loosening Performance
When used in conjunction with spring washers or thread glue, it can effectively prevent loosening caused by vibration.
4
Aesthetics
After installation, the surface is flat without exposed bolt heads, suitable for products with high appearance requirements.
Specifications and Standards
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
1
What is a flat head socket cap screw and how does it differ from a standard socket head cap screw?
A flat head socket cap screw features a flat top surface that sits flush with the workpiece after installation, while a standard socket head cap screw has a cylindrical head that protrudes above the surface. Its conical bottom surface embeds into a pre-made counterbore, delivering a smooth, flush finish that is ideal for appearance-critical or space-constrained applications.
2
What thread sizes and types are available for flat head socket cap screws?
These screws are available in metric coarse threads (such as M4 and M6) and metric fine threads (such as M8 × 1.25), spanning a common diameter range of M2 to M24. Custom lengths and diameters can also be produced to meet specific engineering requirements.
3
What materials are flat head socket cap screws made from?
They are manufactured in carbon steel (with galvanized or blackened surface treatment for general use), stainless steel grades 304 or 316 (for corrosion-resistant environments), and titanium alloy (for lightweight, high-strength applications such as aerospace). The optimal material depends on the operating environment and structural load requirements.
4
Which international standards apply to flat head socket cap screws?
Flat head socket cap screws are manufactured in compliance with ISO 4762 (metric standard) and ANSI/ASME B18.3 (American standard). These standards define head geometry, thread tolerances, mechanical properties, and hexagonal drive specifications to ensure consistent performance and cross-supplier interchangeability.
5
How can I prevent flat head socket cap screws from loosening under vibration?
To resist vibration-induced loosening, use flat head socket cap screws together with spring washers or thread-locking adhesives. The hexagonal drive design also enables higher tightening torques than many other drive types, increasing the clamp force and improving resistance to loosening under dynamic or cyclic loading conditions.
6
What surface treatment options are available and how do they differ?
Three primary treatments are available: galvanizing provides standard rust protection suitable for most indoor or mild environments; Dacromet coating delivers enhanced corrosion resistance at elevated temperatures, making it suitable for automotive and industrial use; electrophoretic coating applies a uniform decorative finish while also offering corrosion protection. Selection should be based on operating temperature, exposure conditions, and aesthetic requirements.