The cold drawn pipe has the characteristics of no air oxide layer on the inner and outer walls, no leakage under high pressure, high smoothness, no deformation after cold drawing, no gap in the flaring and flattening, and the surface layer has been treated with anti-rust treatment. , Pneumatic or hydraulic systems of hydraulic machinery and vehicles and motorcycles, such as cylinders or hydraulic cylinders.
The original link is the drop-down drilling link. This kind of uniform honing will gradually wear off the raised part of the hole edge due to the unevenness of the hole edge, the total contact area between the sharpening stone and the hole edge is not large, and the contact stress is large. However, due to the large contact stress on the surface of the whetstone, coupled with the friction coefficient of the cutting to the whetstone adhesive, the compressive strength of the fusion of the abrasive particles and the adhesive is reduced, so some abrasive particles are under the drilling pressure. Under the effect, it will fall off by itself, and the surface of the whetstone will reveal new abrasive particles, which is the whetstone self-sharpening.
The second stage is to destroy the drilling process. With the development of honing, the surface of the hole is getting brighter and brighter, and the total contact area with the sharpening stone is getting larger and larger, the contact stress of the total area of the enterprise is reduced, and the drilling efficiency is reduced. The other cuts are small and fine, and the friction coefficient of this cutting to the adhesive is not large. Therefore, the abrasive particles of the whetstone fall off very little. At this time, the cutting is not by new abrasive particles, but only by the abrasive particles. Therefore, the load on the tip of the abrasive grains is very large, and the abrasive grains are easily damaged and broken, resulting in a new drilling edge.
The third stage is to block the drilling process. When honing again, the total contact area between the whetstone and the hole surface becomes larger and larger. The ultra-fine cutting deposits deposited on the whetstone and the center of the hole edge are not easy to remove, resulting in blockage of the whetstone. getting brighter. Therefore, the drilling capacity of the whetstone is extremely low, which is equivalent to grinding and polishing. If it is honed again, when the whetstone is clogged seriously and the cohesive force is blocked, the whetstone completely loses its drilling ability and becomes very hot, and the precision and surface roughness of the hole will be compromised.
The cold drawn pipe is produced by extrusion molding, because the surface layer leaves residual compressive stress on the surface layer, which is conducive to the sealing of fine cracks on the surface layer and prevents the expansion of deposition. Therefore, the corrosion resistance of the surface layer can be improved, and the formation or expansion of fatigue cracks can be slowed down, thereby increasing the fatigue limit of cold drawn pipes. According to kneading and forming, a cold-work hardened bottom layer occurs on the extruded surface layer, which reduces the ductility and plastic deformation of the cutting pair touching the surface layer, thereby improving the wear resistance of the inner wall of the cold-drawn tube, and avoiding other problems. Hazards due to cutting. After kneading and molding, the reduction of the surface roughness value can improve the mutual cooperation characteristics.