Tool joints are heavy duty connectors for drill pipe, with thick tapered threads and sealed shoulders, it is used to withstand the weight of drill pipe and the pressure of repeated handling, to resist additional handling during drilling, and to provide leak-proof sealing. Tool joints can be welded to the drill pipe, screwed to the drill pipe, or screwed and welded together.

This article contains the following aspects: 

• The introduction of tool joint

• the function of tool joint

• Conclusion

The introduction of tool joint

1.The tool joint is the threaded joint of the drill pipe, which can provide high strength for the threaded connection. This helps drill pipe to withstand multiple fastening cycles, resulting in loose threads during the drilling process. It is made of steel and has a large diameter section, which can firmly fix the pipe. As required, it can be welded to the pipe or screwed to the pipe. The tool joint is an important part of the drill pipe, so the tool joint manufacturer must ensure that it is manufactured in strict compliance with the international standards of the joint. These tool joints are connected by heat-shrinking technology to ensure long-term reliability of the drill pipe. These components are important for effectively connecting the torque between the work connector and the pipe. These tool joints have stiffness and therefore they can resist fracture or bending of the pipeline during drilling. For this reason, the small incision will not damage the strength or shorten the service life of the pipe. In addition, the tool joints are manufactured separately for optimal results. The hard metal surface is usually used in the outside of the tool joint to enable it to resist the wear of the drill hole wall.

2.The threaded rotary shoulder connection between drill pipes of different lengths is called the tool joint. Usually people use four types of tool joints (or threaded form). Tool joints with specifications defined by the API include all NC connections, 5 1 2 FH, 6 5 8 FH, and API regular connections. 

3.Tool Joint Nomenclature

One shoulder non-api tool joints. For tool joints similar to (sometimes possible) API tool joints. Examples of non-api tool joints are extra holes (eh or xh), open hole (oh), and many others.

Double Shoulder drill joint. The double-shoulder tool joint is provided with a shoulder on the nose of a pin that contacts the internal shoulder in the box. These additional shoulders limit pin deformation and provide greater torsional strength. 

Other proprietary threads. There are other tool joints that do not fall into the former category.

4.Each drill pipe shall be subjected to end drift tests on the drill tool joint and the entire length of the drill tool, and a cylindrical central shaft shall be used with a minimum diameter of 3.2 mm (0.125 inch), which is less than the inner diameter dp specified by the pin end. The length of the drift central axis is at least 100 mm (4 inches). 

The function of tool joint

Tool joints provide high-strength, high-pressure threaded connections that are strong enough to withstand harsh drilling and multiple screwing and loosening cycles. Tool joints are usually made of heat-treated steel and have a higher strength than the pipe body. The large diameter portion of the tool joint provides a low stress area where pipe clamps are used to clamp the pipe. Therefore, the notch caused by the pipe clamp is relatively small and will not cause significant damage to the strength or life of the drill pipe joint. All in all, tool joint is important for the function realization of drill pipe.

Conclusion

Our tool joints are made of good material, fully killed and vacuum degassed using latest clean techniques. drill pipe use this kind of tool joint must be able to withstand tremendous internal and external pressure, torsion, bending and vibration.