In metal press working, a tool that forces a metal to pass through a die under the action of an external force, a metal cross-sectional area is compressed, and a shape and a size of a desired cross-sectional area is obtained is called a draw die. Drawing dies are widely used, such as high-precision wire materials used in electronic devices, radar, television, instrumentation and aerospace, as well as commonly used tungsten wire, molybdenum wire, stainless steel wire, wire and cable wire, and various alloy wires are all pulled by a diamond wire drawing die. Made out of the diamond drawing die due to the use of natural diamond as raw material, which has a very strong wear resistance, high service life. The production process of drawing die inserts includes several process steps such as die pressing, draft drawing and turning. Drawing die is a wire through a mold to make it from coarse to fine, and gradually reach the size required by people. This special type of die is the drawing die. The drawing die is generally made of natural diamonds, synthetic diamonds (synthetic diamonds There are GE, PCD, synthetic materials, etc.) Copper wire drawing die is a soft wire drawing die. There are hard wire drawing die, such as pull tungsten wire, tungsten wire drawing die compression zone angle is relatively small, generally in 12- 14 degrees. Drawing dies include diamond drawing dies, hard alloy drawing dies, plastic drawing dies and the like. Drawing die usually refers to a variety of metal wire drawing molds, as well as pull fiber drawing die. The center of all drawing dies has a certain shape of hole, round, square, octagonal or other special shapes. As the metal is pulled through the die hole, it becomes smaller in size and even changes in shape. A steel mold is sufficient for pulling a soft metal such as gold or silver, and there may be a plurality of holes of different diameters in the steel mold.Drawing dies are widely used, such as high-precision wire materials used in electronic devices, radar, television, instrumentation and aerospace, as well as commonly used tungsten wire, molybdenum wire, stainless steel wire, wire and cable wire, and various alloy wires are all pulled by a diamond wire drawing die. Made out of the diamond drawing die due to the use of natural diamond as raw material, which has a strong wear resistance, a very high service life.1. When the soft metal (such as gold and silver) is used, the steel mold is enough, and the steel mold can have a plurality of holes with different diameters.2. Cemented Carbide Dies—Tungsten carbide nibs are generally used for drawing steel wires (steel wires). The typical structure of this type of die is a cylindrical (or slightly tapering) hard alloy core close together. The ground is embedded in a circular steel case with Bell radius, Entrance angel, Approach angle, Bearing, and Back relief.3, steel wire mold – pull non-ferrous metal wire, such as copper, aluminum, and more similar to the wire drawing die, the shape of the hole is somewhat different.4, polycrystalline silicon mold – pull thin line can be used to polycrystalline diamond (synthetic diamond), as well as the use of natural diamond drawing die.Carbide wire drawing die adopts high-quality hard alloy as the core, which has high hardness, good thermal conductivity and small friction coefficient. Carbide wire drawing die (tungsten steel die) uses high-quality hard alloy as the core, with high hardness, good thermal conductivity, and low friction coefficient. Carbide wire drawing die is simple in production, corrosion resistance, strong impact resistance, low price is a prominent feature of this product, suitable for the drawing of ferrous metals, large size wire, and poor drawing conditions. Cemented carbide is an alloy material made by a powder metallurgical process from a hard compound of refractory metal and a bond metal.Carbide has a series of excellent properties such as high hardness, wear resistance, strength and toughness, heat resistance, corrosion resistance, etc., especially its high hardness and wear resistance, and it remains basically unchanged even at a temperature of 500°C. , It still has high hardness at 1000°C.Cemented carbide is widely used as a tool material, such as turning tools, milling cutters, planers, drills, boring tools, etc., for cutting cast iron, non-ferrous metals, plastics, chemical fiber, graphite, glass, stone, and ordinary steel, but also for cutting. Heat-resistant steel, stainless steel, high manganese steel, tool steel and other difficult-to-machine materials. Carbide has a high hardness, strength, wear resistance and corrosion resistance, known as "industrial teeth" for the manufacture of cutting tools, cutting tools, cobalt and wear parts, widely used in military, aerospace , Mechanical processing, metallurgy, oil drilling, mining tools, electronic communications, construction and other fields, with the development of downstream industries, the demand for hard alloy market continues to increase. In the future, high-tech weaponry and equipment manufacturing, cutting-edge scientific and technological advancement, and rapid development of nuclear energy will greatly increase the demand for high-tech and high-quality and stable carbide products. In the drawing industry of metal products, drawing dies are very important consumable tools. The choice of wire drawing die plays a key role in the quality of the wire drawing die. The physical and chemical properties of wire drawing die must meet the requirements of high hardness, impact resistance, wear resistance, and low friction coefficient. At present, there are carbide die, polycrystalline die and CVD diamond die on the market. Carbide wire drawing die has a lower life than polycrystalline silicon and CVD diamond die, but its cost is relatively low, so it is widely used in the wire drawing industry, and is particularly suitable for drawing wires or profiles with larger diameters (above 8 mm). Carbide drawing die core is generally made of tungsten carbide as a raw material and sintered with a certain amount of cobalt as a binder. Since the binder cobalt has low tensile strength and microhardness, in the wire drawing production, sticking wear and abrasive grain wear easily occur at the contact surface of the wire and the die hole, thereby affecting the ultimate life of the drawing die.The failure of wire drawing die can be divided into two types according to the time of occurrence: normal failure and early failure. Normal failure: After a large number of production and use of the drawing die, natural wear or slow plastic deformation and fatigue cracking occur due to friction. After normal service life, failure is a normal phenomenon and normal failure. Early failure: The mold does not reach the specified time limit for design and use, and it will not only fail due to chipping, chipping, breaking, etc., but also will be unable to continue service due to severe local wear and plastic deformation. For the early failure of the mold, it must look for the reasons for its production, and strive to take remedial measures. After decades of development, many new drawing die materials have emerged. According to the types of materials, wire drawing die can be divided into alloy steel die, hard alloy die, natural diamond die, polycrystalline diamond die, CVD diamond die, and ceramic die. The development of new materials has greatly enriched the application range of wire drawing dies and improved the service life of wire drawing dies.With the deepening of reform and opening up, the domestic industry has successively introduced wire drawing die and corresponding die hole testing instruments manufactured by industrially advanced countries. Through the analysis of foreign wire drawing die holes, we have learned the design ideas of modern wire drawing die holes and provided references for improving the design level of Chinese wire drawing die. The structure of the wire drawing core can be divided into five sections according to the nature of the work: entrance zone, lubrication zone, work zone, calibrating zone, and exit zone. The inner diameter profile of the drawing die is important. It determines the tension required to compress the wire and affects the residual stress in the wire after drawing. The role of the various parts of the core is: the entrance area to facilitate threading and prevent the wire from scratching the wire drawing die from the inlet direction; lubrication zone, through which the wire can be easily brought into the lubricant; the work area, is the main part of the die hole, wire deformation The process proceeds here, reducing the original section to the required section size. When drawing the conical metal, the space occupied by the volume of the metal in the working area is a circular table, which is called the deformation area. The conical half angle α (also called die half angle) in the work area is mainly used to determine the size of the pullout force; the role of the sizing area is to obtain the exact size of the drawn wire; the exit area is used to prevent the wire exit from being unstable And scratch the surface of the wire.With the increase of wire drawing speed, the service life of wire drawing die becomes a prominent problem. Americans T Maxwall and E G Kennth proposed a new wire drawing die theory for high-speed drawing, namely the "linear" theory. The drawing die made according to this theory has the following characteristics:1 The entrance zone and the lubrication zone are combined into one, which has the tendency to reduce the lubrication angle, so that the lubricant receives a certain pressure before it enters the working zone, thus achieving a better lubrication effect.2 The entrance area and work area are lengthened to establish a good lubrication pressure, and the angle is optimized according to the drawing material and the compression ratio per pass.3 The sizing zone must be straight and of reasonable length.4 The vertical line of each part must be straight.See our tungsten carbide nibs for wire drawing die
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