produced from 20MnTiB alloy steel with quenching & tempering heat treatment, marked as 10.9S structural dedicated grade. It includes two types: large hexagon head and torque-shear type, supplied as complete sets with matched high-strength nuts and thick structural washers.

Each batch undergoes strict pre-tension test to ensure stable clamping force, featuring outstanding shear resistance, anti-fatigue and anti-seismic performance for critical heavy-load structural joints. Custom extra-long and oversized special sizes are available for harsh engineering projects. Surface finishes including black oxide, hot-dip galvanized and dacromet can be selected to meet long-term service requirements for indoor and coastal corrosive outdoor environments. Widely used in high-rise steel workshops, bridge engineering, wind turbine towers, heavy machinery, port equipment and large infrastructure frames.