Why does the inner wall of the newly purchased kettle turn black after boiling tea?(two)

in the previous article, considering that the inner walls of the kettles I found are all polished, not electrolytic. The editor also found a kettle with electrolysis process, and also tested these three materials. After passing the same test, the kettle with electrolysis process inside, whether it is 304 stainless steel, 201 stainless steel or 430 stainless steel, has improved significantly, and it is easier to clean. Although the test method is relatively simple, and the test method is not professional and diverse enough, the editor thinks it is enough to satisfy the editor to answer this question for fans and friends.

First of all, when tea is boiled, pigments and theophylline will be released, and theophylline will corrode metals under long-term high temperature conditions. Theophylline contains plant acid and a certain amount of salt, so boiling tea in a stainless steel kettle and soaking it for a long time is equivalent to a similar salt spray test on stainless steel products. After the inner wall of the kettle is slightly corroded, the pigment has a strong adhesion at high temperature, so the interior of the kettle will turn black.

So why are there obvious rust-like rust spots in the kettle? According to the editor's test, the biggest possibility is the material problem, but it does not rule out that the soaking time of fans and friends will exceed the soaking time of the editor's test.

Then I have to mention 430 stainless steel here. Compared with 304 stainless steel, although it is called stainless steel, 430 is not actually stainless steel. In the hardware manufacturing industry, 430 stainless steel is called 430 stainless steel. In fact, this stainless steel does not rust, but it is relatively slow to rust compared to traditional metal iron.

Why is the effect of the electrolytic process much better? This is because the role of the electrolysis process itself is to prevent scratches and corrosion.The detailed process of electrolysis will not be repeated here. Friends who want to know more can search on the Internet. The surface of the inner wall after electrolysis forms a kind of protection, so whether it is 430 stainless steel, 201 stainless steel or 304 stainless steel after electrolysis, the appearance of tea is similar.

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