Metric 8.8 Hex Head Cap Screw

Metric hex head cap screws, grade 8.8 with plain plating, are high-strength fasteners commonly used in a variety of mechanical and structural applications. These fasteners conform to the standards outlined in DIN 931 and DIN 933, two widely recognized international norms. DIN 931 specifies the dimensions for hex head cap screws with partial threads, while DIN 933 defines hex head cap screws with full threads. The grade 8.8 designation indicates that these screws are made from medium carbon steel, heat-treated to achieve a tensile strength of 800 MPa and a yield strength of 640 MPa, making them suitable for a wide range of applications requiring high-strength fasteners.

The plain plating, also known as untreated or uncoated, provides basic corrosion resistance to the screw while maintaining its mechanical properties. The absence of additional coatings like zinc or galvanization helps reduce the overall cost of production. While plain plating doesn't offer the same level of corrosion resistance as more robust coatings, such as zinc, it can still serve well in environments that are not excessively corrosive. Additionally, plain-plated screws retain better torque and friction characteristics, which can be crucial for applications requiring precise control over tightening.

One of the key advantages of plain plating is its simplicity and cost-effectiveness. The lack of coating reduces manufacturing costs and can be beneficial in situations where high corrosion resistance is not the primary concern, but strength and durability are. It also reduces the risk of hydrogen embrittlement, a phenomenon that can occur in coated fasteners subjected to certain environmental conditions.

These fasteners are used in numerous industries, including automotive, construction, machinery, and infrastructure. They are ideal for securing components in engines, machinery parts, structural steelworks, and other high-strength applications where a reliable, durable fastener is needed.