Tungsten Carbide Button Developments

Recent years, due to mechanization and intelligent technology developments, tungsten carbide products used for drilling has a rapid development. The main trends include the following: ultra-fine or nano structure tungsten carbide, high-temperature powder based tungsten carbide, functionally gradient carbide, carbide modified binder, double bonded carbide and WC-Co-diamond three phase composite hard materials and so on.

1. Ultra-fine or nano structure tungsten carbide button: It is one of the hotspot recently. In the early 1990s, related researchers began to focus on grain refining preparing submicron ultrafine and nano-structured carbide launched a study. This is owing to with the continuous grain refinement, the density, the hardness, the toughness and the wear resistance of tungsten carbide materials will be remarkably improved. At the same time drilling equipment for drilling requirements are also getting higher and higher, especially high-pressure drilling of wear resistance and toughness carbide button have strict requirements, and ultrafine grain cemented carbide can fully meet its performance.

2. High-temperature powder based tungsten carbide button: It is one kinds of new process that high-temperature reducing raw material powder and high temperature carbonization, which the preparation of WC powder has integrity, high strength and high energy storage. Compared with conventional vacuum heat treatment, average footage carbide button ratio increased by 50%, drilling speed of nearly 100%, with an average increase of about 100% abrasion resistance, product quality and stability and service life have been greatly improved.

3. Functionally Gradient carbide buttons: In sintering or heat treatment process through the appropriate climate-induced diffusion in the alloy C, and through a chemical reaction so that other members rearrangement and distribution, leading to changes in alloy composition and structure along a certain direction, forming a gradient structure, different parts with different functions. Functionally Gradient carbide buttons usually low carbon alloy carburizing process (pass into CH4, CO and other carbon-containing gas) method of extraction, the treated W and Co ball distribution in the diameter direction. This structure gives button higher wear resistance and toughness, both functionally graded cemented carbide DTH drill, drill or cone ball tooth drill bit life have a significantly improved.

4. New binder modifying carbide buttons: Treatment with molten metal (Ni or Si as alloying additive elements), Ni and Si alloy can significantly improve the ability of anti-fatigue cracks. In addition, Ni sintered alloy melt to permeate the process of WC skeleton occurred off junction formed developed WC / Co sintered alloy phase interface, the grain size is reduced, thereby the fracture toughness increases. The results show that the solder alloy cone rotary drilling bit, the working efficiency is improved by 1.8 times.

5. Double bonded carbide: Compared with conventional tungsten carbide, tungsten carbide pellet is composed of sintered pellets instead of hard compound. The sintered pellets mixed with a binder metal and a second sintering, thereby making the fracture toughness without lowering the hardness of the premise of a substantial increase.

6. WC-Co-diamond three-phase composite hard materials: High temperature high pressure synthesis, powder / polymer mixture extruded into green compacts, and then consolidated by high temperature and pressure synthesis of diamond. It has many advantages, such as reducing the mismatch in thermal expansion and elastic stress off the diamond enhanced; diamond enhanced surface and the wear resistance improved; Fracture toughness of WC-Co- diamond composite surface is excellent, improve service life.

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