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Diamond Wire Drawing Die in Superhard Materials

September 06,2023

1. Definition Of Wire Drawing Die

In metal pressure processing, the metal is forced to pass through the mold under the action of external force, the metal cross-sectional area is compressed, and the tool that obtains the required cross-sectional area shape and size is called a wire drawing die. The wire drawing die is a manufacturer of various metal wires. A very important consumable die for drawing wire. The scope of application of the wire drawing die is very wide. Metal drawing is one of the most common processing techniques for metal materials, and it plays an important role in the production of various cable products such as the wire and cable industry.

2. Material Of Drawing Die

After decades of development, many new wire drawing die materials have appeared in my country. According to the type of material, the wire drawing die can be divided into alloy steel die, hard alloy die, natural diamond die, polycrystalline diamond die,  CVD diamond die and In recent years, the development of new materials has greatly enriched the application range of wire drawing dies and improved the service life of wire drawing dies.

Although wire drawing dies can be used to process various metals and alloy materials such as steel, copper, tungsten, molybdenum, etc., wire drawing dies of different materials have their own applicable processing ranges, and the wear patterns and usage of different materials of wire drawing dies when processing the same wire There is a big difference in life, so it is necessary to choose the drawing die material reasonably to obtain the greatest economic benefits.

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3. The Structure Of The Drawing Die

A complete wire drawing die is mainly composed of a mold core and a mold sleeve. The mold core is mainly composed of five parts: the entrance area, the lubrication area, the working area, the sizing area, and the exit area.(Entrance zone, lubrication zone, compression zone, sizing zone, exit zone)

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4. Diamond Wire Drawing Core

In the field of superhard materials, the manufacture of wire drawing cores is an important application of artificial diamond. Today we will focus on introducing the types of diamond cores

4.1. Single Crystal Diamond Core

Single crystal diamond has the characteristics of high hardness and good wear resistance. The surface finish of the wire drawn by this type of mold is very high. However, due to the anisotropy in the structure of single crystal diamond, its hardness is also anisotropic. The hardness varies greatly within the range, and it is easy to cause severe wear in a certain direction. It is generally used as a fine wire drawing die or a finished drawing die with high surface quality requirements and small diameter. There are two types of single crystal diamond wire drawing cores: natural diamond wire drawing cores and artificial single crystal diamond wire drawing cores.

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4.2. PCD Core

PCD is also called polycrystalline diamond. The successful development of PCD has brought great changes to the wire drawing industry, making the entire processing process more efficient and stable. PCD is sintered by micron-sized diamond particles and binder under high temperature and high pressure conditions. It has the advantages of high hardness, good wear resistance and strong impact resistance. During the use of the mold, it shows the advantages of uniform wear and long life. It is suitable for High speed drawing. Since polycrystalline diamond is isotropic macroscopically, it does not suffer from severe single radial wear, uneven die hole wear and out-of-round die holes like single crystal diamond. In addition, the price of PCD is low, so it is widely used in the wire drawing industry. At present, most diamond wire drawing dies use PCD wire drawing die cores.

According to different binders, PCD mold cores can be divided into two types: cobalt-based and silicon-based. Cobalt-based PCD cores contain metal binders and have good machinability, and can be processed by EDM, laser, ultrasonic and other processes, but the presence of metal cobalt makes diamonds prone to graphitization at high temperatures, so this type of cores Suitable for processing and use under the condition of less than 650°C. The machinability of silicon-based PCD cores is relatively poor, but there is no metal binder in the material, so the material can still maintain good thermal stability at 1000°C.

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4.3.CVD Diamond Core

CVD diamond, also known as chemical vapor deposition diamond, is a pure diamond deposited and grown on the surface of a substrate material by a carbon-containing gas under high temperature and low pressure conditions. CVD diamond has high hardness, good wear resistance, low friction coefficient, and high surface finish. It can be made into a wire drawing die with an aperture of 0.02-1.0mm, which is used to draw stainless steel wire, tungsten wire, copper wire, aluminum wire, etc. Since CVD diamond does not contain any binder, compared with PCD wire drawing die, CVD diamond wire drawing die has the advantages of higher wear resistance, corrosion resistance, thermal conductivity and thermal stability. The disadvantage of CVD diamond wire drawing die is that its toughness is not as good as PCD, its impact resistance is weak, and the technical conditions in the preparation of wire drawing die are stricter than PCD.

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With the rapid development of the manufacturing industry, the research on wire drawing die materials is developing toward high strength, high hardness, and high wear resistance. Various new materials that meet the requirements emerge in an endless stream. The wear resistance of wire drawing dies is greatly improved, and the service life is gradually increased. Processing The accuracy is gradually improved, and the scope of application of drawing processing is gradually expanding.