High strength pre-tension bolt Ⅱ 〔Patent pending〕




High pre-tension: Pretension is one of the most important factors to control the surrounding strata effectively. Facilitated with specially made torque-tension nut and “sandwich” harden washer system, this bolt can increase pretention by 30%-50% compared with other similar bolts.
High strength: Using grade 500 rebar, this bolt has higher capacity. Specially treated thread reduces the steel working hardening and the thread part has the same strength as the rebar.

Technical Merits:
This bolt has been successfully applied in medium strength surrounding strata conditions of deep cover, high stress, without influence of dynamic stress , without yield pillar trend.
Rocbolt Technologies China Ltd