Rock drill is the basic condition, the higher the hardness of the rock, drill with drill rod combined cycle suffered greater stress, the lower its life. Typically, power drills, the higher the frequency of the piston shock, stress the more steep wave piston, the higher the peak, the solder brazing rods are exposed to cyclic stress greater. Rod solder work in corrosive media, the fatigue limit is also a great impact on the steel, shows the influence of media fatigue fatigue limit the impact of the media on the steel steel In the corrosive effects of water, the fatigue limit of steel fell 1 to 5 times. This process of fatigue under the corrosive effect of the media what happened called stress corrosion fatigue. Rod solder during drilling, the water wells have mineral water 19 ~ 39MPa pressure erosion, outside there is mineral water with rock powder corrosion. Indeed, the corrosion in acidic water quality work, easy to solder fatigue drill rod broke off inside occur; work in neutral or alkaline water corrosion, Rod also prone to fatigue breaking outside. So, if you can prevent the mineral water in contact with steel, can greatly improve the life of the drill rod. In summary, under normal drilling conditions suffered drill rod bending, torsional stress, compared with the peak axial stress small. Axial tensile and compressive stress induced fatigue rupture is the main reason for breaking drill rod. Rod inherent defects in steel, smelting, rolling, geometry and parameters, forging, machining, heat treatment, etc., as well as defects, as well as additional bending stress, mechanical abrasion, acid water corrosion, models and rock drilling unfavorable sex, poor bits, incorrect operation, etc., will make this breaking intensified. Changsha Tianhe drilling Machinery Co., Ltd. Contact: Liu Xiao Mobile: 13667359853 18507482826 Website: www.cstianhezj.com E-mail: 1139239907@qq.com Address: Ningxiang Jinzhou District Yao Singapore Industrial Park on the 18th day