Black Hex Structural Bolts

Black Hex Structural Bolts are high-strength fasteners specially designed for heavy-load steel connection scenarios, complying with ASTM A325 and ASTM A490 Type 1 international industrial standards. As a professional fastener manufacturer, Ningbo Gangtong Zheli Fasteners Co., Ltd strictly controls raw material selection for all structural bolt products, only adopting medium carbon alloy steel with stable tensile strength ranging from 830MPa to 1040MPa after quenching and tempering heat treatment. The black oxide finish of Black Hex Structural Bolts forms a compact protective film on the metal surface, improving wear resistance without affecting assembly precision.

Core Production & Technical Advantages

All production procedures of structural fasteners are finished in self-owned automated workshops of Ningbo Gangtong Zheli Fasteners Co., Ltd, including cold heading, thread rolling, heat treatment and surface blackening. The independent heat treatment laboratory carries out tensile, yield and hardness tests for every batch of finished goods, issuing official 3.1 material test certificates for global engineering buyers. The thickened hexagon head design of Black Hex Structural Bolts enhances contact area during tightening, effectively avoiding sliding risks under long-term heavy load, which makes this fastener widely recognized in steel bridge, factory workshop and high-rise steel structure projects.

Inventory & Global Cooperation Support

This series structural fasteners match standard structural nuts and heavy flat washers to form a complete connection assembly set. The mechanical performance indicators of Black Hex Structural Bolts fully meet international building engineering norms, suitable for static load steel frame connection, large equipment support fixing and outdoor steel structure installation. Customized surface treatment solutions including hot-dip galvanizing can be offered if clients need stronger anti-corrosion performance for coastal construction projects.