Stainless steel refers to steel resistant to weak corrosive media such as air, steam, water, and chemically corrosive media such as acid, alkali, and salt (the industry is also called stainless acid-resistant steel). Adding chromium (Cr), nickel (Ni), manganese (Mn), silicon (Si), titanium (Ti), molybdenum (Mo) and other alloying elements in the steel smelting process improves the performance of the steel and makes the steel have corrosion resistance (that is, no rust) is what we often call stainless steel. Stainless steel is a kind of steel that is not easy to rust, and some stainless steels have both stainless and acid resistance (corrosion resistance).
The stainless and corrosion resistance of stainless steel is due to the formation of a chromium-rich oxide film (passive film) on its surface. This rust and corrosion resistance are relative. All stainless steel must contain more than 12% chromium, otherwise it cannot be called stainless steel.
At present, most of the stainless steel products on the market do not specify the content of nickel and chromium, so how should consumers distinguish between high-quality and low-quality stainless steel products? In this regard, many netizens and some so-called "bricks" have offered a trick: use magnets to absorb stainless steel materials to verify their pros and cons and authenticity. Products that cannot be absorbed are considered good and genuine; those that can absorb are magnetic are considered counterfeit. So is this method correct?
This identification method is not scientific enough! Among the five types of stainless steels that have been developed and applied at present, austenitic stainless steels, such as 304, 321, 316, 310, etc., are generally non-magnetic; : Such as 430, 420, 410, etc., or ferrite is magnetic.
However, due to chemical composition fluctuations caused by smelting and stamping, polishing and other processing of 304 stainless steel, the microstructure will also transform to martensitic type, and with weak magnetism, magnets can also be absorbed, and the greater the degree of processing deformation, the martensitic type. The more bulk transformation, the greater the magnetic properties of the steel. Therefore, it is obviously unscientific to judge whether it is 304 stainless steel by whether the magnet can absorb it.
In fact, there is another kind of stainless steel magnet that cannot be attracted.
That is stainless steel with high manganese content and little nickel or no nickel. But this steel will be much cheaper than austenitic steel. Except for these two stainless steels, other stainless steels are attracted by magnets.
Because austenitic stainless steel has low thermal conductivity, it is not suitable to use it as a kettle, frying pan, or rice cooker. It will waste energy and prolong the time for boiling water and cooking. Using ferritic stainless steel to make frying pans and rice cookers not only has excellent corrosion resistance, but also its thermal conductivity is nearly half that of austenitic stainless steel. But this kind of stainless steel is sucked, you can go back and try it.
In this way, we can draw a conclusion: there are many kinds of stainless steel, but only two kinds are not attracted by magnets, one is austenitic stainless steel, which is mostly used for decorative materials, and the other is stainless steel with high manganese content. Other stainless steels such as classified ferrite and martensite are attracted by magnets. Therefore, it is unscientific to use magnetite to identify whether it is stainless steel or not! Guangdong zhenneng Stainless Steel Products Co., Ltd. has been focusing on the research and development and production of stainless steel pots and utensils for many years, looking forward to cooperating with you
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