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Large-Diameter Pdc Composite Sheet Synthesized By Domestic Six-Sided Top Ultra-High Pressure Equipment

September 04,2023

Synthetic PDC materials at home and abroad mostly use two-sided top and six-sided top devices. The ultra-high pressure technology of the double-sided top device is based on the annual ring mold, and the required centering, synchronization, and stability are all solved by the mold. At the end of a cycle of synthesis, the mold needs to be removed from the equipment and reassembled.

There are problems such as leveling and centering in each assembly.

And because the annual ring mold cannot be made very large, it has enough structural rigidity to avoid plastic deformation. Trimming is necessary when the plastic deformation exceeds the precision allowed by the mold. Therefore, although the double-sided top ultra-high pressure device can produce ultra-large-scale PDC materials because its cavity is easy to expand, it has high technical requirements for synthesizing PDC, long synthesis cycle, and low production efficiency.

The alignment, synchronization, and stability of the six-sided roof device are all resolved by the equipment, and can be adjusted. Once adjusted, it can be used for continuous production. Therefore, the production of PDC materials with six-sided top equipment is easy to operate and has high production efficiency.

Comparing and analyzing the stress in the process of synthesizing PDC materials in the two ultra-high pressure devices (see the figure below), it can be seen that when the two-sided top device is synthesized, due to the pressure of the anvil, the mold expands radially outward, resulting in The pressure distribution along the axial direction is high at both ends and low at the center, and the pressure distribution along the radial direction is high at the center and low around; when the pressure is released, the nail hammer is under compressive stress, while the annual ring mold is under tensile stress. In the six-sided roof equipment, since the six top hammers apply pressure to the center at the same time and the pressure can be basically equal, the resultant pressure distribution in the cavity is high around and low at the center; When the pressure is released, each anvil is subjected to compressive stress.

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It can be seen that the radial distribution of the pressure and the temperature distribution are not consistent when the PDC is synthesized by the two-sided top device, but the distribution of the pressure field and the temperature field are consistent when the six-sided top device is synthesized, which is more conducive to realizing the pressure and temperature matching in the synthesis. In particular, the radial compressive stress and axial tensile stress of the composite PDC of the two-sided roof device are easy to cause delamination and cracking of the PDC; while the composite PDC of the six-sided roof device can achieve simultaneous pressure relief during pressure relief, thereby avoiding PDC layering problem. Therefore, the PDC products produced by GE Company and DeBeers Company using the double-sided top device generally need to go through an ultrasonic flaw detector to check whether there is any crack at the joint interface. The PDC produced by the six-sided top device does not need to undergo ultrasonic inspection, and delamination is rare unless there is a problem with the production process.

With the continuous improvement of the new generation of large-scale six-sided roof devices and the continuous expansion of the synthesis chamber, the superiority of the PDC produced by the six-sided roof device will be very obvious. At present, PDC superhard composite materials at home and abroad are developing in the direction of large-scale size and continuous optimization of quality. The enlargement of PDC size and specification is an inevitable product of the development of ultra-high pressure and high temperature technology, and the continuous expansion of the synthetic cavity has created necessary conditions for the manufacture of large-diameter PDC composite tool materials.

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At the same time, with the development of manufacturing technology of PCD and PDC materials and the deepening of research on PDC materials, their performance indicators have been continuously improved and their quality has been continuously optimized. In turn, higher requirements have been put forward for ultra-high pressure and high temperature technology and equipment. The development presents new research topics. The development of superhard materials in my country follows a six-sided top ultra-high pressure technology development path, and the equipment generally adopts hinged six-sided top presses. Compared with foreign annual ring double-sided presses, it is much more difficult to expand the cavity.

With the expansion of the cavity and the increase of the size of the PDC composite sheet, the influence of the key technical problems in the synthesis will be more obvious, and it will be more difficult to control and solve. Undoubtedly, if all points in the cavity can be under the same sintering conditions after the synthesis cavity is enlarged, then the performance of the entire PDC may remain uniform. This is the key to sintering large-diameter high-quality PDC tool materials. To achieve this goal, higher requirements will inevitably be put forward for ultra-high pressure and high temperature technology and equipment, such as improving the stability of the synthesis system; improving the temperature and pressure field uniformity and stability inside the synthesis chamber; improving the stability of sintering conditions. Control accuracy, etc., the solution to these problems will surely promote my country's superhard cutting tool materials to a new level.

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