The finished stainless steel seamless pipe, unless the use occasion is deep underground, the pipe in normal use needs to be polished to ensure that the surface is bright and beautiful. At present, the commonly used polishing methods mainly include mechanical polishing, chemical polishing, and electrochemical polishing.
1. Mechanical polishing
The mechanical polishing method uses a polishing wheel or a polishing belt for processing, wherein the polishing belt uses the abrasive in the polishing agent to polish the surface of the stainless steel seamless pipe in batches, so that the stainless steel seamless pipe surface can achieve a smooth polishing effect.
Mechanical polishing can obtain a mirror-bright surface of less than 0.4 μm. Parts with simple shapes can be polished with hard polishing wheels or polishing tapes, and parts with complex shapes can be polished with soft polishing wheels. Large batches of small parts use batch finishing. Batch polishing can be subdivided into drum polishing, vibrating machine vibrating polishing, centrifuge centrifugal polishing and rotating polishing methods.
Mechanical polishing has a very low amount of grinding on the surface of stainless steel seamless pipes, so it is difficult to polish rough surfaces. At this time, it is necessary to do the polishing process in advance, and use the polishing wheel and the polishing belt to dip the polishing paste for grinding, which is divided into rough grinding, medium grinding and fine grinding. The surface roughness of the stainless steel tube after fine grinding can reach 0.4 μm. In order to meet other individual requirements, such as descaling, deburring, welding slag or pipe surface matting, etc.Surface treatments such as sandblasting, shot peening and wire wheel brushing can also be used, and the use of stainless steel wire wheel polishing can effectively reduce iron contamination.
2. Chemical polishing
Chemical polishing is to immerse parts such as stainless steel seamless tubes in a suitable solution. Since the solution will dissolve the protruding parts on the surface of the stainless steel tube faster, the surface of the stainless steel tube can be flattened to achieve the purpose of polishing. Usually chemical polishing has a weaker polishing power and only slightly enhances the brightness. But it is more labor-saving and time-saving than mechanical polishing, and can also handle the inner surface of small parts.
There are several aspects to be aware of in the chemical polishing process. Because the polishing speed is fast, but the finish is poor, it is more suitable for pre-polishing. Chemical polishing will increase surface activity, be sure to passivate the work surface to ensure corrosion resistance.
3. Electrochemical polishing
Electrochemical polishing can increase the reflective performance of the stainless steel seamless pipe surface, improve the corrosion resistance, reduce the surface hardness of the machined parts, and reduce the friction coefficient due to the reduction of the surface roughness. Electrochemical polishing can also be used to remove burrs, etc. from parts.
Compared with mechanical polishing, the characteristics of electrochemical polishing are as follows
1) Electrochemical polishing will make the stainless steel seamless tube form a passivation surface and improve the corrosion resistance of the material, which cannot be achieved by mechanical processing.
2) Electrochemical polishing has certain requirements on the substrate. For example, when the metallographic structure is uneven, an uneven polishing surface will be formed, and deep scratches cannot be polished flat. Mechanical polishing, on the other hand, has lower requirements on the substrate.
3) The production efficiency of electrochemical polishing is also higher than that of mechanical polishing, but be careful not to put large workpieces.
The surface current density of the electrochemically polished steel pipe must be kept uniform, so that the polished surface brightness will be uniform. Due to the large current during electrochemical polishing, the fixture and the stainless steel seamless pipe must have a large enough contact area and form a good contact. Otherwise, it is easy to cause local overheating and burn out. Finally, it should be noted that some of the processes used to polish austenitic stainless steels cannot be used to polish martensitic stainless steels because they are prone to corrosion.
1. Mechanical polishing
The mechanical polishing method uses a polishing wheel or a polishing belt for processing, wherein the polishing belt uses the abrasive in the polishing agent to polish the surface of the stainless steel seamless pipe in batches, so that the stainless steel seamless pipe surface can achieve a smooth polishing effect.
Mechanical polishing can obtain a mirror-bright surface of less than 0.4 μm. Parts with simple shapes can be polished with hard polishing wheels or polishing tapes, and parts with complex shapes can be polished with soft polishing wheels. Large batches of small parts use batch finishing. Batch polishing can be subdivided into drum polishing, vibrating machine vibrating polishing, centrifuge centrifugal polishing and rotating polishing methods.
Mechanical polishing has a very low amount of grinding on the surface of stainless steel seamless pipes, so it is difficult to polish rough surfaces. At this time, it is necessary to do the polishing process in advance, and use the polishing wheel and the polishing belt to dip the polishing paste for grinding, which is divided into rough grinding, medium grinding and fine grinding. The surface roughness of the stainless steel tube after fine grinding can reach 0.4 μm. In order to meet other individual requirements, such as descaling, deburring, welding slag or pipe surface matting, etc.Surface treatments such as sandblasting, shot peening and wire wheel brushing can also be used, and the use of stainless steel wire wheel polishing can effectively reduce iron contamination.
2. Chemical polishing
Chemical polishing is to immerse parts such as stainless steel seamless tubes in a suitable solution. Since the solution will dissolve the protruding parts on the surface of the stainless steel tube faster, the surface of the stainless steel tube can be flattened to achieve the purpose of polishing. Usually chemical polishing has a weaker polishing power and only slightly enhances the brightness. But it is more labor-saving and time-saving than mechanical polishing, and can also handle the inner surface of small parts.
There are several aspects to be aware of in the chemical polishing process. Because the polishing speed is fast, but the finish is poor, it is more suitable for pre-polishing. Chemical polishing will increase surface activity, be sure to passivate the work surface to ensure corrosion resistance.
3. Electrochemical polishing
Electrochemical polishing can increase the reflective performance of the stainless steel seamless pipe surface, improve the corrosion resistance, reduce the surface hardness of the machined parts, and reduce the friction coefficient due to the reduction of the surface roughness. Electrochemical polishing can also be used to remove burrs, etc. from parts.
Compared with mechanical polishing, the characteristics of electrochemical polishing are as follows
1) Electrochemical polishing will make the stainless steel seamless tube form a passivation surface and improve the corrosion resistance of the material, which cannot be achieved by mechanical processing.
2) Electrochemical polishing has certain requirements on the substrate. For example, when the metallographic structure is uneven, an uneven polishing surface will be formed, and deep scratches cannot be polished flat. Mechanical polishing, on the other hand, has lower requirements on the substrate.
3) The production efficiency of electrochemical polishing is also higher than that of mechanical polishing, but be careful not to put large workpieces.
The surface current density of the electrochemically polished steel pipe must be kept uniform, so that the polished surface brightness will be uniform. Due to the large current during electrochemical polishing, the fixture and the stainless steel seamless pipe must have a large enough contact area and form a good contact. Otherwise, it is easy to cause local overheating and burn out. Finally, it should be noted that some of the processes used to polish austenitic stainless steels cannot be used to polish martensitic stainless steels because they are prone to corrosion.
