至今仍采用高速钢麻花钻钻削强度为900至1100牛顿/毫米~2的实心材料的铁轨。由于高速钢麻花钻的寿命不够理想而设计了一种焊有硬质合金刀片的两刃钻头(图1),该种钻头可进行重磨,然后,钻头报废或将 To date, high speed steel twist drills have been used to drill tracks of solid material with strengths of 900 to 1100 N / mm2. Due to the poor life expectancy of high-speed steel twist drills, a two-edged drill bit (Fig. 1) welded with a carbide insert was designed which can be reground and the drill bits scrapped or