The Red rust is a direct product of metal corrosion in the quality GMP WFI system and can cause component damage. The Red rust is more common in the stainless steel inner wall of the good price and quality GMP WFI system or the stainless steel welded heated part.

When the stainless steel inner wall of the good price and quality GMP WFI system or the outlet of the water point is filtered with a white cloth, yellow or red solid particles can be clearly seen, which is red rust. Under normal circumstances, the probability of red rust in thermal systems such as the good price and quality GMP WFI system and pure steam systems is much higher than that in room temperature purified water systems.
Because water is a very weak electrolyte, the concentration of H+ and OH- in the high-temperature GMP WFI system is much higher than that of purified water at room temperature. The free ferrite in the good price and quality GMP WFI system reacts chemically with OH- in the water, and finally generates FeO after dehydration, thus causing red rust phenomenon in the GMP WFI system.