The stainless steel bowl is discolored, what should I do?

https://www.qing-zhan.com/coffee-kettle/long-spout-304-stainless-steel-pour-over-drip-milk-kettle.html

Hello, in order to reach food grade, the stainless steel bowl is generally made of SUS304 or better material. If it is made of 201 material, it may fade or turn yellow after about half a year after buying it, which is commonly known as oxidation. The surface of finished stainless steel bowls is generally relatively bright, and people can be seen like a mirror. However, the discoloration of stainless steel bowls generally has the following reasons:

1. Stainless steel will turn yellow or brown due to high temperature.

2. If the bowl is exposed to acidic substances such as vinegar and other condiments for a long time, the bowl will not only precipitate heavy metals, but will also gradually oxidize, causing rust or yellowing.

3. Frequent or long-term use of stainless steel bowls to hold salt or high-salt substances (such as sauerkraut, leftovers, etc.) will cause an oxidation reaction between a large amount of chloride ions and the contact surface of the stainless steel, and the pitting area will become larger and larger, which will occur. Visible rust or yellowing. 4. Hard things such as steel balls, cleaning sponges (hard surfaces), etc. are often used to wash dishes, which causes the passivation layer on the surface of the bowl to be destroyed, and small scratches that are exposed for a long time will gradually fade away. Oxidation, causing rust or yellowing

4. There are many other reasons, which are basically related to human operation. The solutions to discoloration caused by all the above reasons are basically the same.

Industrially:

1. Physical polishing method: Use a cloth dipped in polishing paste to polish, and then wash it clean.

2. Electrolytic polishing method: Using stainless steel electrolytic polishing, and then passivating the stainless steel, the bowl can be restored to its original appearance without discoloration for a long time.

3. Pickling passivation method: Use stainless steel pickling passivation solution, soak it briefly and then wash it with water to restore the original color. For home use: it is generally recommended to wipe it with a scouring pad dipped in vinegar or lemon juice, and rub it hard until it shines. After washing with water, remember to wash it again with soda water (3% ratio), pass it through hot water, and then dry it in the sun. You can also get good results. As an aside, pots and pans are made of stainless steel, usually SUS304 or better. , but 201 material is also common. It is generally recommended not to buy too cheap. After all, 201 is relatively more likely to give birth to pigs or release heavy metals, which is bad for health. The screening method is to use a magnet to attract it. If you can feel the magnetism, it may be 201, but it cannot be absorbed. If you feel it is 304, if it is definitely 201, it is recommended to throw it away. If you really can’t bear it, just make a pet bowl. Stainless steel tableware and kitchenware generally need to meet food grade, so you must do stainless steel electrolytic polishing, stainless steel pickling and passivation, or stainless steel. Natural color passivation, thus greatly improving its anti-corrosion and anti-rust performance. If you are interested in this aspect, please contact me and I will help you with a free solution.