About the common screw and the stainless steel screw ingredient question, has the specialized knowledge to come in please
No problem. Seeing yellow is actually a lighter red color. This is only Fe oxidized to Fe2O3. (Fe2O3 red). The generated Fe2O3 is less, so it's yellow. The usual heating apparatus has such a yellow oxidation phenomenon. The heater in my electric kettle is yellow, but I still drink water. It's ok.
The solution is to use stainless steel screws to avoid galvanic corrosion.Boiling water contains very little iron, which has little effect on health.
This is because ordinary screws are made of carbon steel and are prone to galvanic corrosion in moist conditions. Stainless steel is used as positive electrode, and iron or zinc coating on the surface of screws is used as negative electrode to corrode first. Therefore, fading and darkening appear, and the yellow substance on stainless steel is the product of iron oxidation (ferric oxide hydrate).
