Tungsten Molybdenum Wire Drawing Die

The drawing die is an important production mold for the tungsten-molybdenum material industry. It is the key to achieving normal continuous stretching and ensuring the quality of the stretched product. The length of the life of the wire drawing die not only affects the production cost, but also affects the stability of the product quality and production efficiency. This article will combine the company's work experience in the tungsten and molybdenum industry for more than ten years, from the material and structural design of the drawing die itself, the formulation and control of the drawing process conditions, and the use and maintenance of the mold, analyze the service life of the wire drawing die. Various factors and explore effective ways to extend their useful life.

1.The influence of the material of the wire drawing die on its service life

In the process of producing tungsten-molybdenum wire, the commonly used wire drawing die core materials mainly include cemented carbide, natural diamond, synthetic diamond and the like. The core material should be selected according to the different processing steps, the material properties of the processed tungsten-molybdenum wire, and the quality requirements of the tungsten-molybdenum wire. Reasonable selection of core material is the main way to extend its service life.

1.1 Carbide for hard alloy wire drawing die is a carbide with low cobalt content - cobalt alloy, which has good wear resistance, impact resistance, polishing and corrosion resistance, and is easy to repair. Low price, it is commonly used in drawing core molding materials, widely used in the stretching of coarse and medium filaments. Studies have shown that by improving the composition and structure of cemented carbides, controlling the fluctuations in carbon content and refining the particles of carbides, the properties of the materials can be improved and their service life can be extended. At present, domestic and international use of hot isostatic pressing (mP) treatment, ultra-fine crystal process and the addition of rare earth elements to reduce porosity, refine grains, improve the hardness of the alloy, reduce the friction coefficient; and use chemical vapor deposition (C, The method and physical vapor deposition (PvD) method form a diamond film or a titanium nitride coating on the surface of the cemented carbide to improve the surface strength of the alloy.

1.2 Natural diamond Natural diamond, commonly known as diamond, is the hardest substance in nature. It has high wear resistance and thermal conductivity. It can improve the surface quality of wire and improve the performance and size of wire when tungsten or molybdenum wire is stretched. Precision, mainly used for stretching filaments and finished filaments. However, it is very brittle, has poor impact resistance, and has an anisotropic hardness, which is uneven in wear when the wire drawing die is made. In addition, diamond is rare and expensive, and ~n-r_ is difficult, so it is limited in stretching and thickening.

1.3 Synthetic diamond Synthetic diamond, also known as polycrystalline diamond, is a polycrystal formed by the non-directional polymerization of many single crystal particles. It has high strength and hardness, strong impact resistance, uniform properties and good comprehensive performance. In the process of stretching and filament, the service life is higher than that of the diamond mold and the cemented carbide mold, and the wire material is stable in size and good in surface quality. However, the crystal grains of the artificial polycrystalline diamond are coarse and difficult to polish, and the surface roughness of the drawn filament is not as good as that of natural diamond. By refining the crystal grains, the polishing performance can be improved, and the natural diamond can be replaced on the drawing mold of the medium and fine filaments, thereby greatly reducing the cost and improving the product quality.