If the rotary drilling rig has done a continuous function, can be equipped with hydraulic grab or continuous milling wheel construction. If the secondary rope winch with automatic release function, optional percussion drill bit and drilling large diameter drill GRABBING pebbles or boulders. If equipped with gas chambers and faucets can be gas-liquid drilling. If equipped with dual power head or rub into the casing of the machine can be hexagonal hollow drill steel, which is to solve the flow of sand, crushed gravel, silt layer effective construction method. From the standpoint of strength and toughness, after numerous tests rock drill rod, the carbon content of the material was finally set at 0.18%; consider the process performance from the hydraulic drill rod hollow steel, the amount of alloying elements vanadium, and finally get fit manufacturing Rod dedicated new steel 18CrNi3MoV hollow steel, its chemical composition shown in Table 1. After heat treatment (- tempering - quenching - carburizing and tempering), the microstructure shown in Figure 2. Figure 2a is a carburized layer by needle plate martensite and a small amount of residual austenite, and Figure 2b is a heart tissue by tempered lath martensite thereof. Core hardness between HRC42 ~ 46, the strength and toughness to get the best fit, and its mechanical properties are shown in Table 2. And annealing the steel Needless to machining, tempering time is much shorter hollow steel drill rod drilling | Drilling Ltd. Shandong Peng Rui (certified) | hollow steel drill from Shandong Peng Rui Technology Limited The company offers. Drilling Ltd. Shandong Peng Rui (www.zbpengrui.com) Shandong Zibo, metal cutting class leader, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Shandong Peng Rui Drilling Ltd. led the staff warmly welcome all inquiries negotiations to create Shandong Peng Rui Drilling Ltd. a better future.