1.What is the core mechanism?
When the energized plates react with the alkaline solution, a violent electrolytic reaction occurs on the surface of the steel strip, generating a large amount of gas, which is the driving force of the entire cleaning process.
Cathode reaction: When the steel strip acts as the cathode, a reduction reaction occurs on the surface, releasing a large number of tiny hydrogen bubbles.
Reaction formula: 2H⁺ + 2e⁻ → H₂↑
Anodic reaction: When the steel strip acts as the anode, an oxidation reaction occurs on the surface, releasing larger oxygen bubbles.
Reaction formula: 4OH⁻ - 4e⁻ → 2H₂O + O₂↑
2.What accessibility features are available?
Besides degreasing, electrolytic cleaning has another hidden function. In this process, the steel strip acts as the cathode, reducing the silicates in the cleaning solution and depositing a glassy dielectric film approximately 2.3 nanometers thick on its surface. This film is crucial, as it prevents the steel coil from sticking together between layers due to high temperature and pressure during the subsequent annealing process, thus ensuring product quality.
3.Why is electrolytic cleaning more efficient?
Chemical cleaning primarily relies on the emulsifying effect of surfactants to dissolve or displace oil stains from the steel plate. Its effectiveness is limited for dents or tightly bonded stains.
Electrolytic cleaning, building upon the chemical process, incorporates the impact and peeling effects of numerous air bubbles. As these bubbles form, grow, and detach from the steel surface, they continuously impact the oil film, even "pushing" out contaminants hidden in microscopic pits. Therefore, its improvement in surface cleanliness is unparalleled by chemical cleaning.
4.What are the advantages and disadvantages of cathode cleaning (hydrogen evolution)?
High efficiency. Hydrogen bubbles are small and numerous, with a large total surface area, resulting in a strong ability to carry away oil and emulsify, leading to higher cleaning efficiency.
The generated atomic hydrogen may penetrate into the steel matrix, causing hydrogen embrittlement (making the steel brittle) and affecting its mechanical properties.
5.What are the advantages and disadvantages of anodic cleaning (oxygen evolution)?
It eliminates the risk of hydrogen embrittlement and features large oxygen bubbles with strong single-unit carrying capacity, enabling it to more effectively remove solid particles such as iron powder from the surface of the steel strip.
The cleaning efficiency is relatively low, and the corrosion to the equipment (anode plate) is also stronger.