Are stainless steel pans really rust-free? Let's take a look at the composition of the stainless steel pot. The stainless steel pot is due to the addition of a certain amount of chromium alloy elements in the steel, which can form a strong oxide film (passive film) on the surface of the steel, so that the appearance of the stainless steel pot is in contact with the external medium. isolated without chemical interaction. In this type of steel, in addition to containing more chromium (Cr), some also match more other alloying elements, such as nickel (Ni), so that it has good chemical resistance in air, water and steam. Stability, but also has sufficient stability in many kinds of acid, alkali, and salt aqueous solutions, even in high or low temperature environments, it can still maintain its corrosion resistance advantages.
The material commonly used in pots is 304 food-grade stainless steel, 304 stainless steel: steel 18% chromium 8% nickel, can resist chemical oxidation, this stainless steel is 304 in the jis code, so it is called 304 stainless steel, because Its ratio is 18% chromium and 8% nickel, so it is also called 18-8 stainless steel.
Some stainless steel pots are made of 316 stainless steel, which is 18% chromium-10% nickel. This kind of stainless steel will not rust even if 304 will rust in places with serious pollution, so there are The high-end pots in the United States will be made with 10% nickel to make them more durable and corrosion-resistant. This stainless steel is called 18-10 stainless steel.
Utensils made of stainless steel are beautiful and durable. However, unqualified stainless steel pots will have potential safety hazards.
Some compounds in unqualified stainless steel pots may dissolve out during use, and the human body will also slowly accumulate in the body after repeated intake. When it reaches a certain limit, it will endanger human health. Unqualified stainless steel pots are generally unqualified for chromium exceeding the standard. chromium
When we purchase stainless steel pots, in addition to paying attention to the material, we must pay attention to the scene of use, so as to maintain the stability of the stainless steel pot.
Stainless steel is not completely rust-free. If it is exposed to acid and alkali substances for a long time, it will also undergo a chemical reaction to dissolve trace elements in it. Therefore, stainless steel tableware containers should not hold salt, soy sauce, pickled dishes, etc. for a long time; they should not be used to boil Chinese medicine. In addition, do not wash stainless steel tableware containers with strong alkaline or strong oxidizing chemicals such as soda, bleach, sodium hypochlorite, etc., to avoid corrosion to the product.