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China Hexagon Socket Head Cap Bolt DIN 912 - High-Quality Suppliers and Factory Direct Pricing
| Product name | Hexagonal socket screw |
| Size | M6 / M8 / M10 / M12 |
| Grade | 4.8 / 8.8 / 10.9 / 12.9 |
| Material | Steel / Stainless Steel |
| Surface treatment | YZP |
| Standard | DIN / ISO |
| Certificate | ISO 9001 |
| Sample | Free Samples |
Definition and Structural Characteristics
Definition: An internal hexagonal screw is a fastener with a hexagonal groove (internal hexagonal hole) on the head, which requires the use of an Allen Key or a hexagonal screwdriver head matched with an electric tool for installation and removal.
Structural Features:
🔩 Head Types
Common cylindrical heads (ISO 4762 / DIN 912), countersunk heads (DIN 7991), flat heads, etc. — suitable for different installation requirements, such as countersunk heads used in scenarios where flush surfaces are required.
🔧 Thread Type
Full thread or half thread, with various materials and surface treatments available to meet diverse application needs.
Materials and Surface Treatment
Common Materials:
⚙️ Carbon Steel (8.8 / 12.9 Grade)
High strength, widely used in machinery and automotive industries.
🛡️ Stainless Steel (304 / 316)
Corrosion-resistant, suitable for outdoor environments and medical equipment.
✈️ Titanium Alloy
Lightweight with high corrosion resistance, used in aerospace applications.
Application Scenarios
🏭 Industrial Field
Machine tools, molds, automation equipment — high-strength connections that require frequent disassembly.
🚗 Automotive / Aviation
Engine components, chassis — designed for high temperature resistance and vibration resistance.
💻 Consumer Electronics
Laptops, cameras — precision small-sized screws (e.g., M1.6).
🪑 Furniture / Bicycle
IKEA furniture assembly, bicycle brake systems — countersunk design for anti-scratch performance.
Usage Tips
- The wrench should be fully inserted into the bottom of the hole to avoid sliding teeth caused by oblique force.
- When pre-drilling, countersunk screws need to match the taper (such as 90°).
- Regularly check the torque using a torque wrench to prevent over-tightening or loosening.
Frequently Asked Questions (FAQ)
Q What is a hexagonal socket screw and how does it differ from a regular screw?
A hexagonal socket screw (also known as an Allen bolt or hex cap screw) features a six-sided internal recess in the head. Unlike Phillips or slotted screws, it requires an Allen key or hex bit for installation, providing better torque transfer and reducing the risk of cam-out during tightening.
Q What grades are available and what do they mean?
Hexagonal socket screws are available in grades 4.8, 8.8, 10.9, and 12.9. These numbers indicate the tensile strength and yield ratio of the fastener. Grade 12.9 is the highest strength class, commonly used in heavy machinery and automotive applications, while grade 4.8 is suitable for general-purpose, lower-load applications.
Q What is YZP surface treatment and what are its benefits?
YZP stands for Yellow Zinc Plating (also called yellow dichromate zinc plating). It provides a protective coating that significantly improves corrosion resistance while giving the screw a distinctive yellow/gold appearance. It is widely used in industrial and automotive environments where moderate corrosion protection is required.
Q Which material should I choose — carbon steel or stainless steel?
Choose carbon steel (8.8 or 12.9 grade) when high strength is the priority, such as in machinery, automotive, or structural applications. Choose stainless steel (304 or 316) when corrosion resistance is critical, such as in outdoor environments, marine settings, or medical equipment. Stainless steel 316 offers superior resistance to chloride environments compared to 304.
Q Are free samples available before placing a bulk order?
Yes, free samples are available. You can request samples in your required size (M6, M8, M10, or M12), grade, and material to evaluate quality before committing to a large order. Please contact us with your specifications to arrange sample delivery.
Q What standards do these hexagonal socket screws comply with?
Our hexagonal socket screws are manufactured in compliance with DIN and ISO international standards (e.g., ISO 4762 / DIN 912 for cylindrical head cap screws, DIN 7991 for countersunk head screws). The production facility is ISO 9001 certified, ensuring consistent quality control throughout the manufacturing process.