ASME B18.2.6:2019 High Strength Tension Control Hex Head Bolt is suitable for structural steel and high-strength preloaded joints. The tension-control method helps deliver more consistent field tightening results and reduces error from judging installation by torque alone.
The hex head format combines structural load capacity with practical tool compatibility. It can be used in bridges, industrial buildings, towers, equipment foundations, and high-strength node assemblies, with emphasis on preload stability, construction efficiency, and set consistency.
It is usually installed with matching nuts, washers, and dedicated tools. For large projects, batch traceability, friction-surface condition, installation sequence, and final inspection should be managed to ensure overall joint quality.

Dimensions unit: inch
| Thread size | 1/2 | 5/8 | 3/4 | 7/8 | 1 | 1-1/8 | 1-1/4 | ||||
| PP | UNC | 13 | 11 | 10 | 9 | 8 | 7 | 7 | |||
| s | Max. | 0.875 | 1.062 | 1.25 | 1.438 | 1.625 | 1.812 | 2 | |||
| Min. | 0.85 | 1.031 | 1.212 | 1.394 | 1.575 | 1.756 | 1.938 | ||||
| e | Max. | 1.01 | 1.227 | 1.443 | 1.66 | 1.876 | 2.093 | 2.309 | |||
| Min. | 0.969 | 1.175 | 1.383 | 1.589 | 1.796 | 2.002 | 2.209 | ||||
| k | Max. | 0.323 | 0.403 | 0.483 | 0.563 | 0.627 | 0.718 | 0.813 | |||
| Min. | 0.302 | 0.378 | 0.455 | 0.531 | 0.591 | 0.658 | 0.749 | ||||
| ds | Max. | 0.515 | 0.642 | 0.768 | 0.895 | 1.022 | 1.149 | 1.277 | |||
| Min. | 0.482 | 0.605 | 0.729 | 0.852 | 0.976 | 1.098 | 1.223 | ||||
| b | Thread length | Reference Value | 1 | 1.25 | 1.38 | 1.5 | 1.75 | 2 | 2 | ||
| z | Reference Value | 0.5 | 0.6 | 0.65 | 0.72 | 0.8 | 0.9 | 1 | |||
| s1 | Reference Value | 0.32 | 0.43 | 0.53 | 0.61 | 0.7 | 0.8 | 0.9 | |||
① Chemical and mechanical properties should meet the requirements of ASTM F 1852 or ASTM F 2280.
② ASTM A325 / A325M / A490 / A490M / F1852 / F2280 have been merged into ASTM F3125. In the F3125 standard, the above-mentioned six original standard names were changed to bolt grades (for example, the original A325 standard was updated to the A325 grade in F3125).
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Better Fastener is a professional fastener enterprise specializing in the manufacturing of steel washers, stainless steel washers, spring washers and sealingwashers. Founded in 2001 as a washer factory, the company expanded into a comprehensive enterprise integrating washers, nuts, bolts, spring nuts and other fastener products in 2010.
The company positions itself as a provider of comprehensive one-stop services for customers, relying on technological R&D, industrial investment and trade distribution.
With an experienced professional team and a sound sales network, Better Fastener has achieved excellent sales performance in both domestic and foreign markets,and has grown into one of the competitive manufacturers and suppliers in China's industrial fastener industry.
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