Why is the temperature of the chromate passivation solution strictly controlled?

When galvanized steel pipes undergo passivation treatment in a passivation solution, the temperature of the chromate passivation solution used should be strictly controlled below 50°C. If the temperature of the passivation solution is too high, it becomes difficult to form a passivation film on the surface of the galvanized layer. Since the passivation film can dissolve in hot water, even if a passivation film is accidentally formed in the passivation solution, there is a high likelihood that it will eventually dissolve. Therefore, during the passivation treatment process, the temperature range specified in the process specifications should be strictly adhered to.