2026-04-17
What is DTH Drill Pipe and It's Application
DTH drill Pipe is a new drill pipe, which consists of a rod barrel, a male joint and a female joint,which is used in rock drill and crush, anchor drill, geothermal, water well drill, etc. The function of it is to send the down the hole hammer to the bottom of the hole, transmit torque and shaft pressure, and deliver compressed air to the DTH hammers through its center hole. The DTH drill pipe is subjected to complex loads such as impact vibration, torque and axial pressure, and also the sandblasting abrasive effect on its surface caused by the rock slag discharged between the hole wall and the pipe. Therefore, it need have sufficient strength, stiffness and impact toughness.
The DTH drill pipe from our company uses R780/N80 geological steel pipe as the raw material for the rod body and 35CrMo as the joint. After professional friction welding, the welding strength is high. Advanced equipment such as high-precision CNC machine tools are used for production and processing, so that its thread has high-precision linking performance. The use of vacuum conditioning and heat treatment technology ensures the torque of the DTH drill pipe and greatly increases the service life of the DTH drill pipe.
DTH drill pipe specifications and models parameter table
| Rod dia (mm) | Rod Length (mm) | Thickness (mm) | Connect Thread | Wrench Flats (mm) | |
| inch | mm | ||||
| 3 | 76 | 1000-6000 | 5 | API2 3/8”REG | 57/64.5 |
| 3 | 76 | 1000-9000 | 8 | API2 3/8”REG | 57/64.5 |
| 3 1/2 | 89 | 1000-6000 | 6 | API2 3/8”REG | 70/64 |
| 3 1/2 | 89 | 1000-9600 | 8 | API2 3/8”REG | 70/64 |
| 4 | 102 | 1000-9000 | 10 | API2 3/7”REG | 76/89 |
| 4 1/2 | 114 | 1500-7620 | 6 | API3 1/2”REG | 89/95 |
| 4 1/2 | 114 | 1500-9140 | 8 | API3 1/2”REG | 89/95 |
| 4 1/2 | 114 | 1500-9140 | 10 | API3 1/2”REG | 89/95 |
| 4 1/2 | 114 | 1500-9140 | 18 | API3 1/2”REG | 89/95 |
| 5 | 127 | 1500-9500 | 12 | API3 1/2”REG | 89 |
| 5 | 127 | 1500-9500 | 14 | API3 1/2”REG | 89 |
| 5 | 127 | 1500-9500 | 18 | API3 1/2”REG | 89 |
| 5 1/2 | 140 | 1500-9500 | 9 | API4 1/2”REG or 4’FH | 114 |
| 5 1/2 | 140 | 1500-9500 | 10 | API4 1/2”REG or 4’FH | 114 |
| 5 1/2 | 140 | 1500-9500 | 12 | API4 1/2”REG or 4’FH | 114 |
There are connecting threads at both ends of the DTH drill pipe, one end connect to the rotary air supply mechanism, and the other end connect to the down the hole hammer. A DTH hammer drill bit is installed on the front end of the down the hole hammer. When drilling, the rotary air supply mechanism drives the drilling tool to rotate and supplies compressed air to the hollow DTH drill pipe. The down the hole hammer impacts the drill bit to drill the rock. The compressed air discharges the rock ballast out of the hole. The propulsion mechanism moves the rotary air supply mechanism and the drilling tool forward continuously.
DTH drill pipe are mainly used in various drilling constructions such as gas drainage (exploitation) drilling, water exploration holes, and grouting holes in underground coal mines with good stratigraphic conditions. They can also be used in drilling in mining, geology, hydropower and other industries. hole construction, the drill pipe has high strength and is suitable for both conventional drilling and impact rotary drilling.
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