After decades of development, it has appeared in many new drawing die material. According to the type of material can be divided drawing die steel mold, carbide mold, natural diamond dies, polycrystalline diamond dies, CVD diamond and ceramic mold and other mold. Development of new materials greatly enrich the application range of drawing dies and improve the life of wire drawing dies.
Steel mold
(1) alloy steel die is an early drawing die manufacturing materials. The material used to make steel mold mainly carbon tool steel and alloy tool steel. However, due to the hardness and wear resistance alloy die poor, short life, can not meet the needs of modern production, so the steel mold soon be eliminated, has almost not look at the production and processing of steel mold.
Carbide die
(2) it is made of cemented carbide hard metal mold. Tungsten carbide cobalt alloy belong, whose main component is tungsten carbide and cobalt. Tungsten carbide is an alloy of "skeleton", mainly from hard wearing effect; Cobalt is bonded metal, is the source of the toughness of the alloy. Therefore, carbide die and alloy steel mold compared with the following characteristics: high abrasion resistance, good polishing, adhesion is small, the friction coefficient is small, low energy consumption, high corrosion resistance, these features make the Carbide Drawing Mould has extensive processing adaptability, become the most widely used drawing die mold.
The main brands Carbide drawing dies YG8, YG6, YG3, followed YG15, YG6X, YG3X, develop new brands, such as for high-speed drawing YL new grades, as well as from abroad drawing dies grade CS05 (YLO. 5), CG20 (YL20), CG40 (YL30); ZK10, ZK20 / ZK30.
Natural diamond dies
(3) Natural Diamond wire drawing dies is an allotrope of carbon, use it to produce molds with high hardness, good wear resistance characteristics. But natural diamond brittle and difficult to process, generally used in the manufacture of wire drawing die diameter 1.2mm or less. In addition, natural diamond is expensive, shortages, and therefore does not die of natural diamond drawing that is economical and practical tool for people to finally seek.
Polycrystalline diamond dies
(4) Polycrystalline diamond drawing dies is carefully selected high quality synthetic diamond single crystals plus a small amount of silicon, titanium and other binders, polymerization at high temperature and pressure conditions is made. PCD high hardness and good wear resistance, compared to other materials it has its own unique advantages: due to natural diamond anisotropy, in the drawing process, when around the entire hole are in When working condition, natural diamond holes will occur preferentially wear a certain position; and PCD belong polycrystalline, isotropic characteristics, thus avoiding uneven wear and die die orifice holes are not circular phenomenon. Compared with the carbide, polycrystalline diamond carbide tensile strength of only 70% of common, but less than 250% of carbide hard, so making polycrystalline diamond die has more advantages than the carbide die . Drawing Die polycrystalline diamond made with good wear resistance, bore wear uniform, strong shock resistance, high drawing efficiency, and many cheaper than natural diamond. Therefore, polycrystalline diamond dies in drawing widely used in industry.
CVD coating die
(5) CVD (chemical vapor deposition) coating wire drawing dies is a recently developed a new technology, its main way is the Carbide Drawing die coating diamond films. Diamond films are pure polycrystalline diamond, both with single crystal diamond finish, temperature resistance, but also has low abrasion resistance and price of polycrystalline diamond, etc., to achieve well in place of rare natural diamond Drawing Die preparation tools the effect of its widespread use will bring new vitality drawing die industry.
Ceramics mold
(6) high-performance ceramic materials with high hardness, wear resistance, chemical stability, excellent high temperature mechanical properties and easy to bond with the metal, etc., it can be widely used in difficult to machine materials processing.
Nearly three decades, since the ceramic material in the manufacturing process to achieve the effective control of the purity of raw materials and grain size, development of a variety of carbides, nitrides, borides, oxides, whiskers or a small amount of metal additive technology. And using a variety of toughening and strengthening mechanisms, so that the strength of the ceramic material, toughness, impact resistance have been greatly improved.
From foreign research results, ceramic materials have been widely used in the field of mold, it has a number of patents in Japan, the United States, France and other countries. Although the ceramic drawing die in China has not been widely used, but with the continuous improvement of manufacturing technology, ceramics industry will be good for dirmond drawing dies material.
Ceramic wire drawing dies is not easy to adhere to the metal wire drawing process occurs, help to improve the surface properties of the metal wire, especially at high temperature pull-down system colored hard material (such as W, Mo wire, etc.). Ceramic drawing die drawing non-ferrous materials to avoid defects Carbide drawing dies and drawing dies can prolong life and improve the surface quality of the material.
Effect of different materials for drawing dies mandrel Life
Drawing Die common core materials are tungsten carbide, natural diamond, artificial diamond and so on. Drawing mode should be chosen in the core material is selected according to the different manufacturing processes, material properties of the wire to be processed, as well as the quality requirements of the wire. Reasonable choice of core material, is the main way to extend its life.
The following describes the different materials are the core influence on life drawing dies
1. Carbide
Carbide drawing dies with lower cobalt content carbide - cobalt alloy, which has good abrasion resistance, impact resistance, polishing and corrosion resistance, easy to repair and low prices, is a common drawing dies core production materials are widely used in thick, stretching wire. Research shows that by improving carbide composition and structure, control fluctuations in the value of the carbon content, refining carbide particles, can improve the material's performance and extend its life. Domestic and hot isostatic pressing (HIP) process technology and ultra-fine grain adding rare earth elements to reduce the porosity, grain refinement to improve the hardness, reduce friction coefficient; and using chemical vapor deposition (CVD) method and Physical vapor deposition (PVD) method in carbide or diamond thin film formed on the surface of titanium nitride coating to improve the strength of the alloy surface.
2. natural diamond
Natural diamond known as the diamond is the hardest substance in nature, with high wear resistance and thermal conductivity, when used to improve the surface quality of tungsten and molybdenum wire strands extend and improve wire performance and dimensional accuracy, mainly for stretch and finished silk filament. But it is very brittle nature and poor impact resistance, and the hardness anisotropy having each to do when wire drawing dies uneven wear. Coupled with diamond scarce, expensive, processing difficulties, so stretching, thick wire aspect is limited.
3. Synthetic Diamond
Also known as polycrystalline diamond synthetic diamond, which is composed of many single crystal particles of non-oriented polycrystalline polymerization, with high strength and hardness, impact resistance is strong, even nature, good overall performance. In stretching, when the filament life than diamond dies and tungsten carbide die and wire dimensional stability, good surface quality. But synthetic polycrystalline diamond of coarse grains, polishing difficult, stretching the filament surface finish better than natural diamond. By grain refinement can improve polishing performance, replace the natural diamond on the filaments wire drawing dies, greatly reduce costs, improve product quality. |
