M4M6M8 Grade 8.8 High Strength Hexagon Bolt Black Hexagon Screw Extended Screw Hexagon Head Bolt for Mechanical & Construction Use

Our Grade 8.8 High Strength Black Hexagon Head Bolts (Extended Length) are professional-grade fasteners engineered for heavy-duty, high-stress applications across industrial, construction, and mechanical fields. Crafted from premium 8.8 grade carbon steel, these bolts deliver exceptional tensile strength and load-bearing capacity, making them ideal for securing thick materials, heavy components, and high-pressure equipment.

 

The black oxide finish enhances corrosion resistance, wear resistance, and durability, ensuring long-lasting performance in harsh industrial environments, outdoor construction sites, or mechanical installations. Featuring a standard hexagon head design, they allow for easy, secure tightening with common hex wrenches, providing a slip-resistant grip even under high torque—reducing installation time and preventing tool slippage.

 

With an extended length design, these hex bolts offer versatile mounting solutions, perfect for applications requiring extra thread length to fasten deep or thick components (such as machinery frames, construction brackets, industrial equipment, and metal fabrication). Available in popular industrial sizes M4, M6, and M8, they cover a wide range of professional needs, from mechanical engineering and equipment assembly to construction projects and heavy-duty repairs.

 

Designed for reliability and consistency, these bolts are suitable for contractors, maintenance teams, machinery manufacturers, and wholesale buyers. They combine professional-grade strength, easy usability, and long-term durability, making them a trusted choice for any heavy-duty fastening application.