Drawing Die various materials have their own characteristics. Among them, the natural diamond drawing die the most expensive, but also extremely difficult process, but because of natural diamond anisotropy in the radial extent of hardness varies greatly, prone to severe wear in a certain direction, it applies only to natural diamond dies for processing small diameter wire. Carbide lower mold hardness, high modulus carbide wire drawing quality, low surface roughness, but poor wear resistance of carbide die, the short life of the mold. Polycrystalline diamond hardness only to die of natural diamond, because of its isotropic characteristics, it does not produce a single radial wear and tear of the phenomenon, but its price is very expensive, processing difficulties, high manufacturing costs.
CVD diamond coating drawing die due to a good performance and wear resistance, low surface roughness of the wire drawing, but drawing die CVD coating production process is complex, difficult process, high cost; when the coating abrasion After the mold will quickly wear, not only difficult to ensure processing quality, but can not be reused, it can only be scrapped. Carbide ceramic material having a high ratio of hardness and wear resistance, low production costs, is between the production of diamond and carbide drawing dies between the fine material. However, due to the toughness of the ceramic material is poor, poor thermal shock and processing difficulties, has not yet received a wide range of applications.
In a small wire, wire drawing process, the natural diamond, polycrystalline diamond and CVD coating module is commonly used drawing die material. When drawing a small diameter wire, CVD diamond coating to overcome the natural diamond die mold anisotropy, but also has excellent strength and hardness, drawing the highest yield, surface quality meet the requirements. Test proved, CVD diamond coating life drawing die mold identical to the natural diamond, high qualified products, surface quality than domestic polycrystalline diamond. Thus, for small diameter wire drawing, CVD diamond coating drawing die is an ideal choice.
Despite drawing dies it can be used for the processing of various steel, copper, tungsten, molybdenum and other metals and alloys, but drawing die of different materials have their own applicable range of processing, when the processing of different materials the same wire drawing die wear shape and use there is a big difference in life, so a reasonable selection of drawing die material is the key to the successful application of the guarantee. Drawing die of different materials has its relatively reasonable object to be processed. Drawing mainly refers to the reasonableness of the processing of both wire drawing dies and mechanical, physical and chemical properties are matched in order to obtain the longest life of mold. For example, when drawing the same diameter copper wire, PCD die life is 300 to 500 times the carbide die life, and only 80 to 100 times the nickel wire drawing, when drawing molybdenum wire, its Life carbide die life only 50 to 80 times, 60 times and 20 to pull carbon, polycrystalline diamond carbide die life only mode.
As the domestic theory of matching wire drawing dies and the lack of systematic research, led blindly choose, resulting in waste of resources. Drawing die friction and wear situation is very complex, generally divided into two major categories of damage and friction and wear. Drawing Die damage can be divided into cyclic damage, tensile failure, shear failure and the supporting surface destruction, friction and wear can be divided into abrasion wear, friction wear, corrosion, wear, abrasion and fine particles produced by wear. Different operating conditions (wire material, wire drawing die material, lubricants, etc.), so wear and damage drawing die has its own unique process. Wear undermine the relationship between drawing die, in essence, they are interrelated. Drawing Die internal situation can be very subtle, some of the factors that may operate simultaneously, they superimposed role is very complex and difficult to understand. One factor may be the role will cover the role of other factors, the several forms of destruction and friction and wear can often intertwined, for the analysis of damage and wear mechanism increases the difficulty of drawing dies. But in general, the sort from high to low wear of various materials are drawing dies: Diamond Drawing Die (without considering the problem of natural diamond anisotropy) - Ceramic drawing die - hard alloy die - obsolete steel mold.
Through the study of the material drawing die, drawing die is toward high-strength, high hardness, high wear resistance development to meet the requirements of a variety of emerging new materials, drawing dies greatly improved wear resistance, wear time was significantly damaged delay, drawing die life increased machining accuracy has also been improved to some extent. Drawing is gradually expanding the scope of application, from coarse to fine variety of wire can be processed, and the emergence of irregular shaped mold for the processing of wire. |
