Small-diameter precision stainless steel pipes are widely used due to their high corrosion resistance and economic practicality, especially in medical equipment, mechanical parts, experimental equipment, etc. Precision stainless steel pipes should be corrosion-resistant, bright in appearance, and clean and hygienic, and their surface should not be attached to substances that are toxic to the human body. Therefore, the surface treatment of precision stainless steel pipes requires that harmful substances on the surface be completely removed. As a mature surface treatment method, polishing technology has been widely used. Polishing can further improve the corrosion resistance and bright effect of stainless steel.
There are seven commonly used polishing methods at present. Let’s take a look at the small-diameter precision stainless steel pipe processing-polishing process.
1. Mechanical polishing Mechanical polishing is a polishing method that relies on plastic deformation of the surface of the cutting material to remove the convex part after polishing to obtain a smooth surface. Generally, oilstone strips, wool wheels, sandpaper, etc. are used, and manual operation is the main method. For high surface quality requirements, super-fine grinding and polishing can be used. Super-fine grinding and polishing uses a special grinding tool, which is pressed tightly on the surface of the workpiece in a grinding and polishing liquid containing abrasives, and rotates at high speed. This technology can achieve a surface roughness of Ra0.008μm, which is the highest among various polishing methods.
2. Chemical polishing Chemical polishing is to make the microscopic protruding parts of the surface of small-diameter precision stainless steel tubes in the chemical medium dissolve preferentially over the concave parts, to obtain a smooth surface. The main advantage of this method is that it does not require complex equipment, can polish workpieces with complex shapes, can polish many workpieces at the same time, and has high efficiency. The core issue of chemical polishing is the preparation of polishing liquid. The surface roughness obtained by chemical polishing is generally several 10μm.
3. Electrolytic polishing The basic principle of electrolytic polishing is the same as that of chemical polishing, that is, it relies on the selective dissolution of the tiny protruding parts on the surface of the material to make the surface smooth. Compared with chemical polishing, it can eliminate the influence of cathode reaction and has a better effect.
4. Ultrasonic polishing Put the small-diameter precision stainless steel tube into the abrasive suspension and place it together in the ultrasonic field. Relying on the oscillation of the ultrasonic wave, the abrasive is ground and polished on the surface of the workpiece. Ultrasonic processing has a small macroscopic force and will not cause deformation of the workpiece. Ultrasonic processing can be combined with chemical or electrochemical methods. Based on solution corrosion and electrolysis, ultrasonic vibration is applied to stir the solution to separate the dissolved products on the workpiece surface and make the corrosion or electrolyte near the surface uniform; the cavitation effect of ultrasonic waves in the liquid can also inhibit the corrosion process and facilitate surface brightening.
5. Fluid polishing Fluid polishing relies on high-speed flowing liquid and the abrasive particles it carries to flush the surface of the workpiece to achieve the purpose of polishing. Common methods include abrasive jet processing, liquid jet processing, fluid dynamic grinding, etc. Fluid dynamic grinding is driven by hydraulic pressure to make the liquid medium carrying abrasive particles flow back and forth at high speed over the surface of the workpiece. The medium is mainly made of special compounds (polymer-like substances) with good flowability under low pressure and mixed with abrasives. The abrasive can be made of silicon carbide powder.
6. Magnetic grinding and polishing Magnetic grinding and polishing use magnetic abrasives to form abrasive brushes under the action of a magnetic field to grind small-diameter precision stainless steel pipes. This method has high processing efficiency, good quality, easy control of processing conditions, and good working conditions. With suitable abrasives, the surface roughness can reach Ra0.1μm.
7. Chemical mechanical polishing Chemical mechanical polishing technology combines the advantages of chemical polishing and mechanical polishing and is the most commonly used polishing method. While ensuring the material removal efficiency, a more perfect surface can be obtained. The flatness obtained is 1-2 orders of magnitude higher than that of the simple use of these two polishing methods, and the surface roughness from the nanometer level to the atomic level can be achieved. Moreover, the mirror effect of polishing is very bright, without faults, and has good flatness.
The above are seven methods of polishing for small-diameter precision stainless steel pipe processing. Polishing not only has high requirements for itself but also has high standards for surface flatness, smoothness, and geometric accuracy. Surface polishing generally only requires a bright surface. However, since it is difficult to accurately control the geometric accuracy of small-diameter precision stainless steel pipes by methods such as electrolytic polishing and fluid polishing, and the surface quality of chemical polishing, ultrasonic polishing, magnetic grinding polishing, and other methods does not meet the requirements, the processing is still mainly mechanical polishing.
Post time: Jun-18-2024