球墨铸铁深孔钻削时,最主要的矛盾就是排屑。用普通麻花钻钻削,其铁屑既不象钢件那样呈条状,又不象灰铸铁那样呈碎块状。而呈大卷块状,极易堵塞螺旋槽,产生剧烈磨擦。钻削温度升高。钻头退火,孔壁拉毛甚至钻头折断。为此,我们将麻花钻刃磨成如图所示的钻型,钻削效果很好。 Ductile iron deep hole drilling, the most important contradiction is chip evacuation. With ordinary twist drill drilling, the iron scrap is neither as steel as the strip, and not like the gray cast iron as a broken piece. The large volume of block, easily blocked spiral groove, resulting in severe friction. Drilling temperature increases. Drill bit annealing, hole wall or even drill bit broken. For this reason, we twist the twist drill into a drilled shape as shown in the figure, and the drilling effect is very good.