Manufacturers of blast furnace drill pipes have learned that the taphole is not easy to break when drilling the taphole. Under the condition of a certain angle of the taphole of the blast furnace, the taphole channel is stable when the taphole depth increases, which is conducive to the extraction of clean slag iron and promotes the stable and smooth flow of the furnace. The hazard of shallow mouth: the iron mouth is too shallow, and there is no fixed mud bag to protect the furnace wall. Under the erosion and erosion of the slag iron, the furnace wall becomes thinner and thinner, making the iron mouth difficult to maintain. According to the different drilling pressure methods used when drilling, drill rods are divided into three types, friction pressure drill rods, machine lock pressure drill rods and combined pressure drill rods.