EXPERIMENTS AND SIMULATION ON MANNESMANN PIERCING PROCESS IN THE DRILL STEEL MANUFACTURE

Steel drill rods are employed in the mining industry to drill blast holes in rock, for them a high-quality metal surface and accurate geometrical parameters are essential. Drill steel is a special material exclusively designed for drill rods. To estimate the microstructure and dimensional stability of drill steel, a rigid plastic finite element method (FEM) was applied in examining the Mannesmann piercing in the drill steel manufacture. The three-dimensional thermal-force coupling FEM models were computer-generated with different plug positions. The metal deformation during the piercing process was analyzed in detail. The stress-strain state of the metal ahead of the plug was simulated to obtain formation characteristics during the Mannesmann piercing. The effect of the plug position on force and strain rates was also studied with simulation. The results demonstrate that the dimensional stability of hollow drill rods can be enhanced by advancing the plug position.