Chemical Corrosion

Surface Contamination: Oil, dust, and acidic, alkaline, and saline substances adhering to the surface of workpieces can, under certain conditions, transform into corrosive agents. These agents react chemically with certain components in stainless steel parts, leading to chemical corrosion and rust formation.

2. Surface Scratches: Various scratches can damage the passivation film, reducing the protective ability of stainless steel, making it more prone to react with chemical media, leading to chemical corrosion and rust.

3. Cleaning: Inadequate cleaning after pickling and passivation leads to residue accumulation, which directly corrodes stainless steel components (chemical corrosion).

　　Chemical Corrosion

Carbon Steel Pollution: Scratches and corrosion caused by contact with carbon steel components form galvanic cells with the corrosive medium, leading to electrochemical corrosion.

Cutting: The attachment and corrosion of materials prone to rust, such as slag and spatter, form galvanic corrosion due to the formation of an electrochemical cell with the corrosion medium.

3. Roasted School: The components in the flame heating area and the metallic microstructure change unevenly, forming an electrolytic battery with the corrosive medium, leading to electrochemical corrosion.

Welding: Physical defects in the welding area (such as undercut, blow holes, cracks, incomplete fusion, and incomplete penetration) and chemical defects (like coarse grain, chromium depletion at grain boundaries, segregation, etc.) form galvanic cells with the corrosive medium, leading to electrochemical corrosion.

5. Material: Chemical defects in stainless steel (such as uneven composition, S and P impurities, etc.) and surface physical defects (looseness, sand holes, cracks, etc.) are conducive to the formation of galvanic cells with corrosive media, leading to electrochemical corrosion.

6. Passivation: Poor pickling passivation results in uneven or thin passivation film on the surface of stainless steel, which is prone to electrochemical corrosion.

7. Cleaning: The remaining acid pickling passivation residue and the products formed by the chemical corrosion of stainless steel with the stainless steel components form electrochemical corrosion.