Polycrystalline Diamond Wire Drawing Die

The hardness of polycrystalline diamond mold is second only to natural diamond. Because of its isotropic characteristics, it does not cause a single radial wear increase phenomenon, but its price is very expensive, processing is difficult, and manufacturing cost is high.

(4) Polycrystalline diamond is formed by a carefully selected high quality synthetic diamond single crystal and a small amount of a bonding agent such as silicon or titanium, which is polymerized under high temperature and high pressure conditions. Polycrystalline diamond has high hardness and good wear resistance. Compared with other materials, it has its own unique advantages: due to the anisotropy of natural diamond, during the drawing process, when the entire hole is around In the working state, the natural diamond will have preferential wear at a certain position of the hole; and the polycrystalline diamond belongs to the polycrystalline and isotropic characteristics, thereby avoiding the phenomenon that the die hole is unevenly worn and the die hole is not round. Compared with cemented carbide, the tensile strength of polycrystalline diamond is only 70% of that of commonly used cemented carbide. However, it is 250% harder than cemented carbide, which makes the polycrystalline diamond mold have more advantages than the cemented carbide mold. The wire drawing die made of polycrystalline diamond has good wear resistance, uniform inner hole wear, strong impact resistance, high wire drawing efficiency, and the price is much cheaper than natural diamond. Therefore, polycrystalline diamond molds are widely used in the drawing industry.

For example, when drawing a copper wire of the same diameter, the service life of the polycrystalline diamond mold is 300 to 500 times that of the hard alloy mold, and only 80 to 100 times when the nickel wire is drawn. When the molybdenum wire is drawn, The service life is only 50-80 times of the life of the cemented carbide mold. When drawing the carbon steel, the life of the polycrystalline diamond mold is only 20 to 60 times that of the cemented carbide mold (the comparison of the service life of the polycrystalline diamond and the hard alloy) 1). Due to the lack of systematic research on the matching theory of drawing die and wire rod in China, blind selection has been made, resulting in waste of resources. The friction and wear of the wire drawing die is very complicated, and it is generally divided into two categories: damage and friction and wear. The damage of the wire drawing die can be divided into ring breaking, tensile failure, shear failure and support surface failure, etc. Friction and wear can be divided into abrasion wear, friction wear, corrosion wear, scratch and wear caused by fine particles. The working conditions (wire material, wire drawing material, lubricant, etc.) make the drawing die wear and tear have a unique process. The interrelationship between the wear and tear of the wire drawing die is essentially interrelated. The inside of the wire drawing die can be very subtle, and some factors may work at the same time. Their superposition is very complicated and difficult to understand. It is possible that the effect of one factor will mask the effects of other factors. The above-mentioned forms of damage and friction and wear may often be intertwined, which makes it difficult to analyze the mechanism of damage and wear of the wire drawing die. But in general, the order of wear resistance of various material drawing die from high to low is: diamond wire drawing die (does not consider the problem of natural diamond anisotropy) - ceramic wire drawing die - cemented carbide die - Abandoned alloy steel mold. Through the study of the material of the wire drawing die, the wire drawing die is developing towards high strength, high hardness and high wear resistance. Various new materials meet the requirements, and the wear resistance of the wire drawing die is greatly improved, and the time of wear and destruction is obvious. Delay, the life of the drawing die is increasing, and the machining accuracy is also improved. The application range of the drawing process is gradually expanding, and the wire of various specifications ranging from coarse to fine can be processed, and the special-shaped mold for processing the irregular wire appears.