GB/T21839 steel used in precast concrete in torsion and wrap test, test velocity is not more than 30r/min, steel wire wrapping speed is adjustable between 10r/min – 60rmin, NDW-JR10 high strength torsion and wrap test machine completes test with precast steel wire of strength 1860Mpa, 2275Mpa, PC bar, precast steel strand.