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| Causes of serious damage of diamond drawing die |
1กข Improper use of diamond drawing die in the process of drawing leads to rapid wear of the die
(1). The drawing compression ratio is too large, which leads to cracks or breakage of the drawing die. Most of the cracks or fractures are caused by the release of internal stress. In any material structure, the existence of internal stress is inevitable. The internal stress generated during wire drawing can enhance the microcrystalline structure of the die. However, when the drawing compression ratio is too large and the lubrication cannot be timely conducted, resulting in too high temperature rise, some materials on the die surface will be removed, and the internal stress borne by the microcrystalline structure will be greatly increased, making it easier to crack or break.
(2). The asymmetry between the drawing axis of wire rod and the center line of die hole leads to the uneven internal stress of wire rod and drawing die, and the impact of mechanical vibration will also cause high stress peak value for wire rod and drawing die, both of which will accelerate the wear of die. The uneven hardness of wire rod caused by uneven annealing is easy to cause fatigue damage of diamond drawing die and form annular groove, which aggravates the wear of die hole.
(3). Rough surface of wire rod, oxide layer, sand or other impurities on the surface will make the die wear too fast. When the wire passes through the die hole, the hard and brittle oxide layer and other adhesion impurities will cause the die hole of the drawing die to wear and scratch the wire surface as abrasive.
(4). Poor lubrication or metal debris impurities in lubricating oil lead to die wear. If the lubrication is not smooth, the surface temperature of die hole will rise too fast and diamond grains will fall off, which will lead to die damage. When the lubricating oil is not clean, especially when it contains metal debris falling off during drawing, it is easy to scratch the surface of die and wire rod.
2กข The diamond drawing die causes rapid wear due to its own quality factors
The results show that:
(1). The unsymmetrical inlaying between diamond drawing die blank and die steel sleeve, uneven distribution of inlaid cemented carbide steel sleeve or the existence of gaps, all of which easily lead to U-shaped cracks in the process of wire drawing.
(2). Unreasonable pass design of diamond drawing die, too small opening of inlet lubrication area and too long setting area will lead to poor lubrication and wear or even fragmentation of drawing die.
(3). In the process of laser drilling, if the sintering marks are not cleaned up or heated unevenly, the metal catalysts and binders in the diamond layer will be gathered into a pile, which will easily lead to the pit in the die during the drawing process. |
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