Stainless steel polishing

Stainless steel has a wide range of applications. After polishing, it can further improve the surface finish, and can also form a new protective layer on the surface, so that the molecular structure of stainless steel is more firm, chemical reaction will not occur easily, and the service life of materials will be improved. Today, we will talk about stainless steel polishing.

There are many methods for polishing stainless steel, including mechanical polishing, chemical polishing, electrolytic polishing, magnetic abrasive polishing, etc.

1. Mechanical polishing

Mechanical polishing is a polishing method that obtains a smooth surface by removing the convex parts after polishing through cutting and plastic deformation of the material surface. It generally uses oilstone strips, wool wheels, sandpaper, etc. Special parts such as the surface of the rotating body can use auxiliary tools such as a turntable. For high surface quality requirements, ultra precision polishing can be used. Ultra precision polishing is the use of specially designed grinding tools, which are tightly pressed onto the machined surface of the workpiece in a polishing fluid containing abrasives and perform high-speed rotational motion. By utilizing this process, a surface roughness of Ra0.008 um can be achieved, which is commonly used in optical lens molds.

2. Chemical polishing

Chemical polishing is the process of allowing materials to preferentially dissolve the micro protruding parts of the surface in a chemical medium, resulting in a smooth surface. The main advantage of this method is that it does not require complex equipment and can polish workpieces with complex shapes. It can simultaneously polish many workpieces with high efficiency. The core issue of chemical polishing is the preparation of polishing solution. The surface roughness obtained by chemical polishing is generally several 10um.

3. Electrolytic polishing

The basic principle of electrolytic polishing is the same as that of chemical polishing, which involves selectively dissolving small protrusions on the surface of the material to make the surface smooth. Compared with chemical polishing, it can eliminate the influence of cathodic reaction and achieve better results. The electrochemical polishing process is divided into two steps:

(1) Macroscopic leveling, diffusion of dissolved products into the electrolyte, decrease in geometric roughness of the material surface, Ra>1um.

(2) Low light level, anodized, increased surface brightness, Ra<1um.

4. Ultrasonic polishing

Place the workpiece in an abrasive suspension and place it together in an ultrasonic field, relying on the oscillation effect of the ultrasonic wave to grind and polish the abrasive on the surface of the workpiece. Ultrasonic machining has low macroscopic force and will not cause deformation of the workpiece, but it is difficult to make and install tooling. Ultrasonic machining can be combined with chemical or electrochemical methods. On the basis of solution corrosion and electrolysis, ultrasonic vibration is applied to stir the solution to separate the dissolved products on the surface of the workpiece, and the corrosion or electrolyte near the surface is uniform; The cavitation effect of ultrasound in liquids can also suppress the corrosion process, which is conducive to surface brightening.

5. Fluid polishing

Fluid polishing relies on the high-speed flow of liquid and its carried abrasive particles to wash the surface of the workpiece to achieve the purpose of polishing. Common methods include abrasive jet machining, liquid jet machining, hydrodynamic grinding, etc. Hydrodynamic grinding is driven by hydraulic pressure, which causes the liquid medium carrying abrasive particles to flow back and forth through the surface of the workpiece at high speed. The medium is mainly made of special compounds (polymer like substances) with good flowability under low pressure and mixed with abrasives, which can be silicon carbide powder.

6. Magnetic abrasive polishing

Magnetic abrasive polishing