Analysis of Wear Causes of PCD Drawing Die
1 The quality of the drawing die itself causes the die to wear out
(1) The diamond die blank and the die steel sleeve are inlaid asymmetrically, and the sintered hard alloy steel sleeve is unevenly distributed or has voids, which
easily leads to U-shaped cracks in the process of drawing the wire;
(2) During the laser drilling process, the pcd blanks are not cleaned or unevenly heated, which may cause the metal catalysts and binders in the diamond layer
to aggregate into a pile, which may cause pits in the mold during the drawing process;
(3) The design of the die hole type is unreasonable. The opening of the entrance area is too small, and the bearing length is too long, which may result in poor
lubrication, resulting in wear or even chipping of the die.
2 Improper use of the wire drawing process leads to die wear
(1) The drawing surface shrinkage rate is too large, causing cracks or breakage of the die Most of the cracks or broken cracks are caused by the release of internal
stress.In any material structure, the presence of internal stress is inevitable, and the internal stress generated when drawing the wire can enhance the diamond microcrystalline
structure. However, when the drawing surface shrinkage rate is too large, it cannot be lubricated in time, and the temperature rise is too high, which leads to the part of the
material of the diamond surface removed, and the stress on the microcrystalline structure is greatly increased, making it more prone to cracking or fracture.
(2) The tensile axis of the wire is asymmetric with the center line of the die hole, resulting in uneven stress on the wire and the wire drawing die, and the impact of
mechanical vibration also causes high stress peaks on the wire and the wire drawing die, both Both will accelerate the wear of the mold.
(3) Factors such as uneven hardness of the wire due to uneven annealing tend to cause premature fatigue damage of the diamond wire drawing die, forming an annular
groove and aggravating die hole wear.
(4) The surface of the wire is rough, and the surface adheres to the oxide layer, sand or other impurities, which causes the mold to wear too fast. When the wire passes
through the die hole, the hard, brittle oxide layer and other adhering impurities can cause the wire die hole to wear quickly and scratch the wire surface like the abrasive.
(5) The lubrication is not smooth or the lubricating oil contains metal debris and the mold is worn. Poor lubrication will cause the surface temperature of the diamond die
hole to rise too fast during drawing, and the diamond grains will fall off, resulting in damage to the die. When the lubricating oil is unclean, especially if it contains metal
scraps that fall off during drawing, it is easy to scratch the surface of the die and wire.
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