Cold drawn seamless pipes have the characteristics of no oxidation layer on the inner surface, no leakage under high pressure, precision machining, high glossiness, no deformation during cold drawing, no gap during expanding and flattening, and rust prevention treatment on the surface. They are important for mechanical structures, hydraulic equipment, and pneumatic or hydraulic transmission systems of cars and motorcycles, such as cylinders or hydraulic cylinders.
1.The initial stage is the down milling stage. This kind of symmetrical honing is slow, because the hole edge is uneven, the Sharpening stone and the hole edge contact area is not large, the contact stress is large, and some of the protrusions on the hole edge are quickly removed. However, due to the large contact stress on the surface of the Sharpening stone and the friction resistance of drilling to the Sharpening stone binder, the bonding tensile strength of the grinding particles and the binder is reduced. Therefore, some grinding particles fall down independently under the effect of milling pressure, and new grinding particles are exposed on the surface of the Sharpening stone, which is called Sharpening stone self sharpening.
2.The second ring joint is the stage of crushing and milling. With the honing, the hole surface becomes more and more smooth, and the area of contact with the Sharpening stone becomes larger and larger. The contact stress of the company’s area decreases, and the milling efficiency decreases. In addition, the cut drilling is small and fine, and this type of drilling has little frictional resistance to the adhesive. Therefore, few particles fall from the grindstone to grind the yarn. At this time, the drilling is not based on new grinding particles, but only on the point milling of grinding particles. Therefore, the load on the grinding particles is very high, and the grinding particles are prone to damage and collapse, resulting in new milling edges. Stainless steel plate bright tube, stainless steel plate heat exchanger tube, seamless steel pipe with diameter
3.The third stage is the blocking and milling stage. When honing again, the contact area between the Sharpening stone and the hole surface is getting larger and larger. Extra fine drilling is piled up in the middle between the Sharpening stone and the hole edge, which is difficult to clean, resulting in the Sharpening stone being blocked and becoming more and more smooth. Therefore, the professional ability of Sharpening stone milling is extremely low, which is equivalent to polishing. If the Sharpening stone is seriously blocked due to re honing, which leads to adhesive blockage, the Sharpening stone is lack of milling professional ability and seriously heats up, and the accuracy and surface roughness of the hole will be damaged.
Cold drawn seamless pipes are produced by extrusion processing. Due to the residual compressive stress field on the surface, they are beneficial for sealing small surface cracks and preventing the expansion of sedimentation. Thus improving the surface ability and alleviating the cause or expansion of fatigue cracks, thereby increasing the fatigue limit of cold drawn seamless pipes. According to extrusion processing, the extrusion processing surface creates a layer of cold work hardening layer, reducing the plasticity and brittle fracture of the contact surface during drilling, thereby improving the wear resistance of the inner wall of cold drawn seamless pipes, and avoiding the harm caused by drilling. After extrusion processing, the reduction of surface roughness value can improve the mutual matching characteristics.
Post time: Aug-01-2023