The reasons for the corrosion of bearing and rust prevention method
As everyone knows, the bearings are precision mechanical parts, to be require high precision and high surface finish degree, and the corrosion will make the stainless steel bearing to loss the original precision and finish degree, directly affect the using performance of bearing, and reduce the service life, or even scrapped.
Main factors affecting metal corrosion
Metal corrosion is caused by various internal and external factors, to be summed up and mainly has:
A, chemical composition and structure of metal materials;
B, metal surface finish (oxygen concentration difference of battery corrosion);
C, solution composition and pH value in contact with metal surface;
D, ambient temperature and humidity;
E, a variety of environmental media in contact with the metal surface.
Analysis of corrosive reason of stainless steel
- Chemical corrosion of stainless steel
Which attached on the surface, the oil, the dust, and acid, alkali, salt, etc. will translate into the corrosive media in a certain condition, will have a chemical reation with some compositions of stainless steel parts, to produce the chemical corrosion and rust.
The damage of a variety of scratches to passive film, to cause the protection of stainless steel reduced, what are the precautions of self priming pump in the installation and use? It is easy to have the reaction with chemical medial to produce the chemical corrosion and rust.
The cleaning is not clean after picking and deactivation to result in residual liquid, directly corrode the stainless steel parts (chemical corrosion).
- Electrochemical corrosion of stainless steel
Scratches caused by contacted with carbon and corrosion media to form the electrochemical corrosion.
Adhesion of cutting slag, splash and liable rust substance form a galvanic cell with the corrosion medium to produce electrochemical corrosion.
The composition of flame heating zone and metallurgical structure changed and uneven, to form a galvanic cell with the corrosion medium to produce electrochemical corrosion
The physical defects in the weld zone (undercut, pores, cracks, lack of fusion, lack of penetration etc.) and chemical defects (coarse grain, grain boundary segregation, chromium depleted) and corrosion media to form a galvanic cell and to produce electrochemical corrosion HPsdw5.
Chemical defects of stainless steel (inhomogeneous component, S, P impurity and so on) and surface physical defect (porosity, sand holes, cracks and flaw etc.) are conducive to formation of primary battery with corrosion media and produce electrochemical corrosion.
The bad effect after picking and deactivation causes the uneven or thin stainless steel surface passive film, easy to form the electrochemical corrosion.
Remaining picking passivated residue and production of chemical corrosion of stainless steel and stainless steel part to form the electrochemical corrosion.
3 stress concentration is easy to cause stress corrosion.
The following are several antirust methods of bearing:
A, Surface cleaning: cleaning must be based on the surface nature of the anti-rusted thing and the time of the condition , to choose the appropriate method. Commonly used are solvent cleaning method, Chemical cleaning method and mechanical cleaning method.
B, after surface drying and cleaning, you can use dry with filtered compressed air, or dry with 120 degrees~170C degrees, and can wipe dry with clean gauze.
The method of coating antirust oil
A, immersion method is that some small things adopt to be immersed in anti rust grease, let to adhere a layer of antirust grease on its surface. The thickness of oil film can be reached by controlling the temperature or viscosity of antirust grease.
B, brush coating method is not suitable for immersion or spray of outdoor construction equipment or special shaped products, you should not only pay attention to not generate accumulation when you brush, but also pay attention to prevent leakage coating.
C, the spraying method is that some large antirust things can’t adopt immersion method to oil, generally use filtered compressed air of about 0.7Mpa pressure to spray on where the air is clean. The spraying method is suitable for solvent dilution type antirust oil or thin layer antirust oil, but it must adopt prefect fire prevention and labor protection measures.
Therefore, it is an essential step to do the antirust job well.