With the trend of modernization and informatization, the technicality of metal surface treatment is becoming more refined and stable. Today, I'd like to discuss the processing technology of stainless steel passivation. The common processing technologies for stainless steel passivation include two main categories: immersion-type stainless steel passivation liquid and wiping-type stainless steel passivation paste. Both of these processing methods are relatively simple, clear, and convenient. However, although the processing methods are relatively straightforward, they are not without their limitations during the production process. So, what are the reasons that affect the actual effect of stainless steel passivation?
1. Stainless steel sheet components inherently contain elements that can impair the effectiveness of passivation treatments. The passivation capability of stainless steel sheet components is largely dependent on their passivability. Among the constituent elements of stainless steel sheet components, chromium and nickel are highly passivatable, while iron has a lower passivability. Therefore, the higher the content of chromium and nickel, the stronger the passivability of the stainless steel, and also, the reliability of the coating improves with the increase in chromium and nickel content.
2. The production and processing of stainless steel plate components can pose certain hazards to passivation treatment. Before stainless steel passivation, components that have undergone surface finishing processes such as drilling, polishing, and buffing have a stronger passivation ability. However, those processed through sandblasting, forging, and other methods have a rougher surface, resulting in weaker passivation effects.
3. The presence of other elements in stainless steel sheets can negatively impact the effectiveness of passivation treatment. Elements such as manganese, carbon, and silicon can be detrimental to the passivation process, while sulfur and selenium are even worse. Therefore, if such elements are present in the surface layer, they should be removed thoroughly prior to passivation.
4. Components of stainless steel plates that have been nitrided, high-frequency quenched, soldered with tin, and fibrous-welded cannot be treated with stainless steel passivation liquid or paste. This is because after passivation, it may compromise the quality of the preceding process.
Therefore, if you receive steel parts from customers that require passivation, you should first assess the condition of the steel parts and apply stainless steel passivation solution accordingly. Then, further reduce the corrosion resistance of the steel parts and enhance their rust prevention capabilities, exceeding the satisfactory passivation effect required by the customer.
