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What’s the manufacturing process in drill pipe?

Views:1     Author:Site Editor     Publish Time: 2020-04-21      Origin:Site

Manufacturing drill pipe is a serious business. Advanced drilling products bring advanced machinery, knowledge and craftsmanship to an industry that requires careful attention to detail. We produce drill pipes with attention to detail and manufacturing quality control. Just because the pipeline is small does not mean that work is less important. You can browse our manufacturing process below.

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This article contains the following aspects:

  • The manufacturing process in drill pipe

  • Conclusion


The manufacturing process in drill pipe


We start with a special chemical carbon alloy tube. Our 4130 carbon alloy billet tube started to run, the process was heated to 2300 degrees by a gap furnace. When the required temperature is reached, the tip is fixed in a precision-machined mold. The forging center punch pushes 2300 degrees of steel into the groove of the die, making forging possible. After the forging is completed, inspect the forging from the inside to the outside, and then grind the edge of the molten steel between the dies.

2. Heat treating

The forged drill rod enters a series of induction coils and a gas furnace for austenitizing, and is then heated to 1650 degrees. Immediately after leaving the austenite furnace, the tube was quenched with a polymer-based fluid to determine the final micro structure, which made the steel very hard. At this point, steel is too hard to use on hard drives because its brittleness can cause it to break. Therefore, the drill pipes are sent directly into the furnace, where they are heated again. This time, however, it only rose by about 1,000 degrees. This step uses the sharp grain structure of steel, completely relaxing, making it both hard and durable. The steel is heat treated with S135, which means it weighs 135,000 pounds. Tensile strength per square inch. Some drill pipes on the market can reach 110 pounds, or 110,000 pounds, just after heat treatment. Higher tensile strength means that the drill pipe can withstand longer bending and rotation fatigue. Heat treatment is a very professional process and can lead to disastrous results if not handled properly. 

3. The straightness 

Furnace applied a lot of energy to the blank tube, which unfortunately was not very straight. Therefore, after coming out of the tempering furnace, the tube enters the cross roller and sleeve type straightener and is calibrated there. After straightening and QC inspection, the drill pipes will be sent to the next process or into the warehouse for the next order.

4. Weld Prep: “Turn and Face”

5. In order to obtain the best and most consistent welding on an inertial welding machine, the outer diameter of the forged drill pipe must be reduced and the weld surface (face) must be machined. This ensures that each welded part has an equal welding area diameter and that all surfaces are uniformly welded by inertial welding. 

6. Threading

In our machine shop, the threading of tool joints is performed simultaneously with turning and end operations. Tool joints are made by experienced mechanics, pay attention to details, and are committed to efficient manufacturing. After each tool joint is completed, it will be inspected using a JSS measuring system. In addition to providing normal measurements commonly used to evaluate the "good quality" of tool joints, JSS can also measure the pitch of tool joints. The pitch diameter is the key to the measurement, which cannot be achieved with the old industry standard ring plug gauge. The pitch indicates how the threads mesh with each other when the pin and box thread are twisted together. Better participation means better tools, better tools means less time to worry about the drill pipe when you send the drill pipe to do a job.

7.Inertia Welding

The “welded” part of the inertia welding usually causes some confusion. Tool joints and forged tube bodies are actually welded to each other, but do not normally use the term 'weld'. In this process, the inertia welding machine uses the counterweight spindle to fix the tool joint. The spindle is then rotated to a very specific RPM. Once the proper RPM is reached, the drive motor disengages from the engagement and the spindle can rotate freely through the inertia gained by increasing the weight. Then press the tool joint and forging tube body together under controlled pressure until the spindle stops rotating. The force applied by this pressure and the heat produced by rotational mass is sufficient to transform carbon alloy steel into a plastic state. It is this state of plasticity that fuses two (previously separate) parts together into a robust part. Interestingly, the process can be used to weld dissimilar metals together, such as bronze with aluminum or titanium with brass.

8.Post-Welding Tempering

The heat generated during inertia welding changes the grain structure of s135 heat-treated steel in the welding zone. The welding area of the tool joint and the drill pipe body is restored to the S135 hardness and tensile range, and the welding area is placed in the induction coil and tempered.   


9.Final Inspection

After the welding and tempering are completed, the outer diameter can be cleaned for final inspection. First, check the angle and parallel alignment of the tool joint and the drill pipe body to ensure that the weld is successful and that tolerances are met. The mechanical properties of the drill pipe body were then checked according to specifications developed by the American Petroleum Institute (api). Once the previous quality inspection has been completed, the tube is briefly magnetized and immersed in a liquid containing suspended metal particles. If cracks or inclusions occur during welding, the metal indicator will be attracted to the defect and clearly show the inspector a failure that has not been seen before. Once all the criteria have been met, we will spray a protective coating on the drill pipe for you to use.


After reading the above production process, I believe you already have some knowledge of the manufacturing process in drill pipe. Our company is a standout in the production of drill pipe, our products are made of high quality steel, all spare parts are strictly inspected before they leave the factory. We are honored to provide you with service.



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