Hydrophilicity polishing mechanism of stainless steel tube surface!

Current location: Home >> News >> Exhibition information

Hydrophilicity polishing mechanism of stainless steel tube surface!

2020-06-20 H:32:34

Stainless steel pipe is easy to process widely used in the field of petrochemical industry with harsh environment. The wettability of stainless steel pipe surface is an important factor affecting the mass transfer separation process on its surface. Therefore, it is of great practical significance to analyze the wettability of stainless steel pipe surface, which has good flexibility, corrosion resistance, high temperature resistance, tensile strength, water resistance excellent power supply Magnetic shielding performance, stainless steel pipe can be freely bent into various angles radius of curvature, stainless steel pipe has the same flexibility durability in all directions, the stainless steel pipe pitch is flexible, has good expansion contraction, no blockage rigidity phenomenon, the stainless steel pipe threading hose between the side buckle.

In recent years, the analysis of this aspect has been widely concerned. However, the stainless steel pipe surface treatment method proposed is relatively complex, the industrialization is relatively difficult. The analysis shows that the chemical oxidation method is effective Improve the corrosion resistance of stainless steel pipe.

Chemical oxidation treatment can improve the hydrophilicity of stainless steel tube surface, its hydrophilicity increases with the increase of oxidation temperature oxidation time. The optimal process conditions are as follows: oxidation temperature is 75 ℃, oxidation time is 8 min.

Chemical oxidation treatment can greatly increase the content of oxygen polar groups in the surface thickness range of stainless steel pipe, enhance the surface free energy polar component of stainless steel pipe, so as to effectively improve the hydrophilicity of stainless steel pipe surface.

Stainless steel tube has good passivation layer on the inside outside surface, so it has strong corrosion resistance. The internal external surface finish of stainless steel pipe is high, the medium adhesion is little, which is conducive to corrosion resistance. The surface finish of stainless steel pipe is high, the liquid medium retention is less, which is conducive to flushing, especially in pharmaceutical field.

Electrolytic polishing (electropolishing): the electrolytic polishing solution is phosphoric acid, sulfuric acid, chromic anhydride, gelatin, potassium dichromate, etc. the inner surface of the stainless steel pipe is on the anode, the polishing fluid flows in through low voltage high current. At this time, the inner surface of the tube goes through two contradictory processes, namely, the passivation layer on the metal surface (containing thick The formation dissolution of the film are due to the different conditions of film formation passivation between the convex part the concave part of the surface, as well as the anodic dissolution.

The conditions of passivation of stainless steel tube are different because the micro convex part concave part of the surface form film, because of the anodic dissolution, the metal salt concentration in the anode area increases continuously, a thick membrane with high resistance appears on the surface of the stainless steel pipe. The thickness of the film at the concave convex position is different, resulting in the high current density on the anode surface, the discharge dissolution speed is fast, so that the protruding micro part can be flattened in a short time Under this effect, the chromium content in the inner surface of the tube is increased, the corrosion resistance of 304 stainless steel pipe with passivation layer on the metal surface is increased.

How to master the polishing quality of stainless steel tube is related to the electrolyte formula, concentration, temperature, electrifying time, current density, electrode condition, surface treatment boundary of the tube, etc. if the technology is mastered well, the surface finish of the tube will be damaged. If the electrolytic state is too high, more concave convex surfaces will appear, even the tubes will be scrapped. The technology is needed to make the quality of stainless steel tubes good, the cost is high.

Machine polishing of inner surface of pipe: there are rotary linear polishing. Take rotary machine polishing as an example: machine polishing equipment is relatively simple, power polishing disc are relatively simple; power polishing disc are relatively simple; polishing wax is used; cloth disc cloth disc made of graded fine sand particles are used to polish the inner outer surface of the pipe for multiple passes, the finish can be as high as RA ≤ 0.2-0.4 μ M.

Compared with electrolytic polishing, stainless steel tube has simple equipment, low technical content, easy to master, low cost, won't destroy the tube cause scrap, so it is widely used.