The main brands of cemented carbide drawing dies are YG8, YG6 and YG3, followed by YG 15, YG6X and YG3X. Some new brands have been developed, such as YL for high-speed drawing, and imported CS05(YLO.5), CG20(YL20) and CG40 (YL30). ZK 10, ZK20/ZK30 .(6) High-performance ceramic materials have the characteristics of high hardness, good wear resistance, strong chemical stability, excellent high-temperature mechanical properties, and are not easy to bond with metals, which can be widely used in the processing of difficult-to-machine materials.
In recent thirty years, due to the effective control of raw material purity and grain size in the manufacturing process of ceramic materials, various addition technologies of carbides, nitrides, borides, oxides, whiskers or a small amount of metals have been developed. As well as various toughening and strengthening mechanisms, the strength, toughness and impact resistance of ceramic materials are greatly improved.
From the foreign research results, ceramic materials have been widely used in the field of molds, and there have been many patents in Japan, the United States, France and other countries. Although ceramic wire drawing die has not been widely used in China, with the continuous improvement of manufacturing technology, ceramics will be a good wire drawing die material suitable for wire drawing industry.
Ceramic wire drawing die is not easy to adhere to metal wire during wire drawing, which is beneficial to improve the surface properties of metal wire, especially for drawing colored hard materials (such as W and Mo wires) at high temperature. Drawing nonferrous metals with ceramic wire drawing die can avoid the defects of cemented carbide wire drawing die, prolong the life of wire drawing die and improve the surface quality of materials.
Effect of different material cores on the life of wire drawing die
The core materials commonly used in wire drawing die mainly include cemented carbide, natural diamond, artificial diamond and so on. When selecting the wire drawing die, the core material should be selected according to different processing procedures, the material properties of the processed wire and the quality requirements of the wire. Reasonable selection of core material is the main way to prolong its service life.
The effects of different material cores on the service life of wire drawing die are introduced below.
1. cemented carbide
Cemented carbide for wire drawing die is a kind of carbide-cobalt alloy with low cobalt content, which has good wear resistance, impact resistance, polishing and corrosion resistance, easy repair and low price. It is a common material for making wire drawing die core, and is widely used for drawing thick and medium wires. The research shows that by improving the composition and microstructure of cemented carbide, controlling the fluctuation of carbon content and refining carbide particles, the properties of the material can be improved and its service life can be prolonged. Hot isostatic pressing (HIP) treatment, ultra-fine grain process and addition of rare earth elements are used at home and abroad to reduce porosity, refine grains, improve alloy hardness and reduce friction coefficient. Chemical vapor deposition (CVD) and physical vapor deposition (PVD) are used to form diamond film or titanium nitride coating on the surface of cemented carbide to improve the surface strength of the alloy.
2. Natural diamond
Natural diamond, commonly known as diamond, is the hardest substance in nature and has high wear resistance and thermal conductivity. It can improve the surface quality, performance and dimensional accuracy of tungsten-molybdenum wire, and is mainly used for wire drawing and finished wire. However, it is brittle, with poor impact resistance and anisotropic hardness, and it is easy to wear unevenly when making wire drawing dies. In addition, diamond is scarce, expensive and difficult to process, so it is limited in drawing medium and thick wires.
3. Synthetic diamonds
Synthetic diamond, also known as polycrystalline diamond, is a polycrystal formed by non-directional polymerization of many single crystal particles, with high strength and hardness, strong impact resistance, uniform performance and good comprehensive performance. When drawing medium and thin wires, the service life is longer than that of diamond die and cemented carbide die, the wire size is stable and the surface quality is good. However, the grain size of synthetic polycrystalline diamond is coarse and it is difficult to polish, and the surface smoothness of drawn filaments is not as good as that of natural diamond. By refining the crystal grain, improving the polishing performance, replacing natural diamond on the drawing die of medium and fine wires, the cost is greatly reduced and the product quality is improved.