阿萨斯是是是是是是所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所所多绿According to the practical problems encountered in horizontal directional drilling, a detailed analysis of the loads in the drilling process and fatigue mechanism has been done. Based on the above, the paper have predicted the fatigue life of the dill pipes, and proposed the measures for improving the fatigue life. According to the practical problems encountered in horizontal directional drilling, a detailed analysis of the loads in the drilling process and fatigue mechanism has been done. Based on the above, the paper have predicted the fatigue life of the dill pipes, and proposed the measures for improving the fatigue life. According to the practical problems encountered in horizontal directional drilling, a detailed analysis of the loads in the drilling process and fatigue mechanism has been done. Based on the above, the paper have predicted the fatigue life of the dill pipes, and proposed the measures for improving the fatigue life. According to the practical problems encountered in horizontal directional drilling, a detailed analysis of the loads in the drilling process and fatigue mechanism has been done. Based on the above, the paper have predicted the fatigue life of the dill pipes, and proposed the measures for improving the fatigue life. According to the practical problems encountered in horizontal directional drilling, a detailed analysis of the loads in the drilling process and fatigue mechanism has been done. Based on the above, the paper have predicted the fatigue life of the dill pipes, and proposed the measures for improving the fatigue life. According to the practical problems encountered in horizontal directional drilling, a detailed analysis of the loads in the drilling process and fatigue mechanism has been done. Based on the above, the paper have predicted the fatigue life of the dill pipes, and proposed the measures for improving the fatigue life. According to the practical problems encountered in horizontal directional drilling, a detailed analysis of the loads in the drilling process and fatigue mechanism has been done. Based on the above, the paper have predicted the fatigue life of the dill pipes, and proposed the measures for improving the fatigue life. According to the practical problems encountered in horizontal directional drilling, a detailed analysis of the loads in the drilling process and fatigue mechanism has been done. Based on the above, the paper have predicted the fatigue life of the dill pipes, and proposed the measures for improving the fatigue life.

15# steel