... : underground support 3.Diameter : 16mm 18 mm 20mm 22mm 25mm Rock Bolt is used together with dome plate and net for ... the longitudinal direcition , rock body has equal tensile strength ,that is about 40% higher than the reverse-twist bolt in the same ... STRENGTH Mpa (Min.)YIELD STRENGTHMpa (Min.)ELONGATIONMpa (Min.)Thread Bar Rock Bolt: M16, M18, M20, M22, M25 available, different length available ...