How to polish stainless steel flat bar

There are many kinds of surface states of stainless steel flat bar. Generally, as masterbatch for mirror grinding, there are 2B, BA, HL, mirror and so on. The main materials suitable for mirror grinding are austenite such as SUS304, 304J1, 316L, 201, 202, 430, 441, and ferritic stainless steel. The final mirror effect is also determined by the material and surface of the masterbatch. For example, the grinding effect of 300 series stainless steel is slightly better than that of other series materials, BA surface grinding effect is the best, 2B is the second, No. 1 is the worst. In addition, the contact between the polishing emulsifier and the circulating system of the polishing emulsifier, together with the corrosion of various acidic and alkaline substances, requires that the polishing emulsifier and the polishing machine have good corrosion resistance. In addition, due to the high-speed rotation of the polishing machine and the friction of metal plates, a lot of heat (especially the poor thermal conductivity of austenitic stainless steel) is generated in the same area due to the grinding work, which will cause the change of metal surface stress, thus affecting the micro-change of metal physical state, and ultimately lead to metal. Flatness, so polishing equipment and polishing environment are required to have good heat dissipation conditions.

At present, the common polishing methods for stainless steel flat bar are as follows, The following polishing methods are used not only for stainless steel flat steel but also for stainless steel profiles, stainless steel round bar and so on.

1. Mechanical polishing is a polishing method to obtain a smooth surface by cutting and removing the convex part of the polished surface of stainless steel flat bar by deformation. Generally, oilstone strips, wool wheels, abrasive paper, etc. are used. Manual operation is the main method. Ultra-precision polishing is a special abrasive tool. In the polishing fluid containing abrasives, it is pressed on the surface of the workpiece and rotates at high speed. The surface roughness of Ra 0.008 um can be achieved by this technology, which is the highest among all polishing methods. This method is often used in optical lens moulds.

2 Chemical polishing chemical polishing is to dissolve the micro-protruding part of the material in the chemical medium in preference to the concave part, so as to obtain a smooth surface. The main advantage of this method is that it does not need complicated equipment, can polish complex workpieces, can polish many workpieces at the same time, and has high efficiency. The key problem of chemical polishing is the preparation of polishing fluid. The surface roughness obtained by chemical polishing is generally 10 microns.

3. The basic principle of electropolishing and electropolishing is the same as that of chemical polishing, that is to say, the surface of electropolishing and electropolishing is smooth by selectively dissolving the small protruding parts on the surface of materials. Compared with chemical polishing, the effect of cathodic reaction can be eliminated and the effect is better. The electrochemical polishing process can be divided into two steps: (1) macro-leveling the dissolution product diffuses into the electrolyte, the surface geometry of the material decreases, and Ra > 1 micron. (2) Low-light level anodic polarization, surface brightness increased, Ra < 1 micron.

4. Ultrasound polishing puts the stainless steel flat bar into the abrasive suspension and puts it together in the ultrasonic field. The abrasive is polished on the surface of stainless steel flat bar by means of the oscillation of the ultrasonic wave. Macroscopic force of ultrasonic machining is small, which will not cause deformation, but it is difficult to manufacture and install the tooling. Ultrasound processing can be combined with chemical or electrochemical methods. On the basis of solution corrosion and electrolysis, ultrasonic vibration stirring solution is applied to separate the dissolved products on the surface of stainless steel flat bar, and the corrosion or electrolyte near the surface is uniform. The cavitation effect of ultrasound in the liquid can also inhibit the corrosion process and facilitate the surface brightening.

5 Fluid polishing fluid polishing relies on the high-speed flow of liquid and abrasive particles to wash the surface of stainless steel flat bar to achieve polishing purposes. Common methods include abrasive jet processing, liquid jet processing, hydrodynamic grinding, etc. Hydrodynamic abrasion is driven by hydraulic pressure, which makes the liquid medium carrying abrasive particles flow through the workpiece surface at high speed. The medium is mainly made of special compound (polymer material) with good flowability under low pressure and mixed with abrasive. The abrasive can be made of silicon carbide powder.

6. Magnetically abrasive polishing (MAP) is to use magnetic abrasives to form abrasive brushes under the action of magnetic field to grind stainless steel flat bar. This method has high processing efficiency, good quality, easy control of processing conditions and good working conditions. With suitable abrasive, the surface roughness of stainless steel flat bar can reach Ra 0.1 um.