Organic chemical corrosion
1. Surface environmental pollution: oil stains, dust, acid, alkali, salt, etc. adhering to the surface of the steel parts are converted into corrosive substances under certain standards, and chemical changes occur with some components in the stainless steel plates, causing organic chemical corrosion and corrosion.
2. Surface scratches: Various scratches destroy the passivation film, which reduces the maintenance capacity of the stainless steel plate, and is easy to react with organic chemicals, causing organic chemical corrosion and rust.
3. Cleaning: After the phosphating treatment is not cleaned up, the residual liquid remains, and the stainless steel plate is immediately corroded (organic chemical corrosion).
Photoelectrocatalytic corrosion
1. Carbon steel environmental pollution: scratches and corrosive substances caused by contact with carbon steel parts produce galvanic cell reaction and cause photoelectric catalytic corrosion.
2. Laser cutting: cutting slag, splashing and other easily corrosive chemical substances adhere to and corrosive substances to produce galvanic reaction and cause photoelectric catalytic corrosion.
3. Roasting school: The composition and alloy composition in the area where the flame is heated changes unevenly, and it reacts with corrosive substances to cause the photoelectric catalytic corrosion.
4. Electric welding: the physical disadvantages of the electric welding area (wrong mouth, vent, crack, unwelded, incomplete penetration, etc.) and organic chemical disadvantages (the crystal is thick, the grain boundary is poor in chromium, shrinkage, etc.) and corrosive substances The galvanic cell reaction causes photoelectrocatalytic corrosion.
5. Material: The organic chemical shortcomings of metal materials (uneven composition, S, P residues, etc.) and surface physical defects (loose, sand holes, cracks, etc.) are beneficial to the galvanic reaction with corrosive substances and cause photoelectric catalytic corrosion.
6. Passivation treatment: The actual effect of phosphating treatment is not very good, resulting in uneven or thin passivation treatment film on the surface of stainless steel plate, which is convenient for photoelectric catalytic corrosion.
7. Cleaning: The remaining phosphating treatment residual liquid and the reaction product of the organic chemical corrosion of the stainless steel plate and the stainless steel plate produce photoelectric catalytic corrosion.