Diamond and cemented carbide are the main materials for wire drawing die processing.There are great differences between the two materials and each has its own characteristics.
Diamond is a kind of mould material with the highest hardness,excellent wear resistance, brittleness and high price.This kind of drawing die is very difficult to process. Generally,the die with wire diameter less than 1.0mrn is made.At present,the diameter of the largest diamond die has reached 2.5mrn.
Tungsten cobalt cemented carbide is used,which is composed of tungsten carbide and cobalt.Tungsten Carbide is hard and wear-resistant,which is the "skeleton" of the alloy.Cobalt is the bonding metal,which increases the toughness of the alloy.With the increase of cobalt content,the density,hardness,compressive strength,elastic mold number,thermal conductivity and resistivity of the alloy decrease,while the toughness and bending strength increase.With the increase of WC content,the properties of the alloy are just opposite to those with the increase of CO content.
Cemented carbide has good properties of high wear resistance,corrosion resistance,alkali resistance,anti emulsion and other lubricating materials.Cemented carbide wire drawing die is widely used in drawing production of various metals and alloy wires.
The following by the drawing die manufacturer to introduce the different material of the die core on the drawing die service life
1.Carbide Drawing Die
Cemented carbide for wire drawing die is a kind of carbide tungsten cobalt alloy with low cobalt content.It has high wear resistance,impact resistance,abrasiveness and corrosion resistance.It is easy to repair and cheap.It is commonly used as drawing die core material and is widely used in drawing thick and medium wires.The results show that according to the composition and structure of cemented carbide tools,controlling the fluctuation of carbon content and micro optimizing cementite particles can improve the material properties and prolong the service life.At present,the hot isostatic pressing (hip) solution,ultra nano microcrystalline processing technology,organic chemical liquid deposition (CVD) method and physical liquid deposition (PVD) method are used to produce diamond plastic film or titanium nitride coating on the surface of cemented carbide tools,which can improve the compressive strength of aluminum alloy surface strength.
2.Natural Diamond Drawing Die
Natural diamond is the hardest and hardest material in nature,with high wear resistance and thermal conductivity.It can improve the surface quality of steel wire,enhance the performance and dimensional accuracy of steel wire,and is mainly used for wire drawing and finished steel wire.However,its properties are brittle,poor impact resistance,isotropic hardness and uneven wear of drawing die.In addition, diamond is scarce,the price is relatively expensive,and the difficulty coefficient of production and processing is large,so it is limited in drawing and thick wire.
3.Artificial Diamond Drawing Die
Synthetic diamond,also known as polycrystalline diamond,is a single crystal made of many polycrystalline silicon particles and undirected polymer.It has high toughness and strength,strong impact resistance,symmetrical characteristics and excellent comprehensive performance. In the process of wire drawing,precision line and service life,it is higher than that of diamond die and cemented carbide die,with stable wire size and good surface quality.However,the grain size of Synthetic Polycrystalline Diamond is coarse and it is difficult to grind.The surface roughness of drawn filament is worse than that of natural diamond.By refining the grain, the polishing performance is improved,and the natural diamond can be replaced on the drawing die of medium and fine wire,which greatly reduces the cost and improves the product quality.
The hardness and wear resistance of synthetic diamond are second only to natural diamond,better than cemented carbide,and its price is obviously lower than natural diamond.Polycrystalline drawing die made of man-made diamond has been used in rough drawing,medium drawing copper wire and steel wire production.
Other die material steel is low cost,easy to process and repair,but it has low hardness,poor wear resistance and short service life. After 1970s,it has been replaced by cemented carbide and diamond.
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