Does stainless steel bearing need rust preventive maintenance? The answer is yes!
As for stainless steel bearing, due to the special micro-structure and surface passivation membrane of stainless steel materials, making it difficult occurring a chemical reaction with the medium and corrosion in general case, but it doesn’t mean it can’t be corroded at any conditions. In the condition of existing the corrosive medium and inducement (such as scratch, splash, cutting slag, etc.), the stainless steel can also have a slow chemical reaction with corrosive medium and be corroded, and the speed of corrosion is so quick in certain condition and produce corrosion phenomena.
The reasons of the chemical corrosion:
1.Surface contamination: the oil, dust, acid, alkali and salt attachedon the bearing surface will transfer to corrosive medium, perform a chemical reaction with some of the stainless steel and producing the chemical corrosion and rust.
2.Surface scratch: various damages to passivation membrane because of scratch, reducing protection ability of stainless steel, it’s easy to react with the chemical medium, and producing the chemical corrosion and rust.
3.Improper cleaning: the residue remaining after not clearly cleaning of pickling passivation, it will corrode the stainless steel bearing directly.
The reasons of electrochemical corrosion:
1.Carbonsteel pollution: scratches and corrosive media touching with carbon steel will form primary battery and resulting in electrochemical corrosion.
2.Cutting: adhesion and corrosion media of rust substance such as cutting slag and spatter will form primary battery and resulting in electrochemical corrosion.
3.Baking proofreading: composition and microstructure of flame heating area have a change and becomes uneven, it will form primary battery and resulting in electrochemical corrosion.
4.Welding: the physical defects (bite edge, porosity, crack, incomplete fusion, incomplete fusion, ) and chemical defects(coarse big grains, grain boundary poor chromium, segregation and so on) of welding area will form primary battery and resulting in electrochemical corrosion.
5.Material: the chemical defects (uneven composition, S, P impurities, etc.) and physical surfacedefects（loose, sand holes, crack, ）of stainless steel material are good to form primary battery and resulting in electrochemical corrosion.
6.Passivation: pickling passivation ineffective will result in uneven or thinthickness of stainless steel surface passivation membrane, it’s easy to form electrochemical corrosion.
In the stainless steel bearing production, we should take all effective measures to avoid corrosion conditions and incentives. In fact, many conditions and incentives (damage, spatter, cutting slag, etc.) have a significant disadvantage effect for appearance quality of production, which must be overcome. The followings are some common ways of stainless steel bearing anti-rust which Lily bearing recommends to everyone.
1.using anti-rust oil
a.Soakingmethod: soak the stainless steel bearing in anti-rust oil, making its surface adhesion adhere a layer of anti-rust oil. The oil film thickness can be achieved by controlling the temperature of anti-corrosive grease or viscosity.
b.Brushing method: the bearing products used for inapplicable soaking or spaying outdoor building equipment or special shape. Brushing should not build up, but also prevent leakage.
c.Spraying method: some large stainless steel bearings can’t adopt soaking way to apply oil, in generallyusing the filtered compressed air of about 0.7 Mpa pressure filter for spraying in clean air. Spraying method used solvent diluting type rust-proof oil or thin layer rust-proof oil, in addition, must adopt perfect fire protection and labor protection measures.
a.Surface cleaning: the cleaning must according to the stainless steel bearing’s surface characters and recent conditions, choosing the suitable ways. There are usually used solvent cleaning, chemical cleaning and mechanical cleaning.
b.Surface drying: after cleaning you can use filterable dry compressed air to dry, or use 120~170℃ dryer to dry, you can also use the cleaning cloth to wipe dry.
Dealing with some common acids will result in the rust of stainless steel, and people’s sweat also can lead to rust the stainless steel bearings. Therefore, when we need to use the stainless steel bearing in normal times, it is best to wear gloves or finger-stall to touch stainless steel bearing, and regularly coated with anti-rust oil to protect stainless steel bearings.