Can a strong magnet absorb stainless steel?

Stainless steel is becoming more and more popular with its beautiful appearance, corrosion resistance and non-destructive advantages. There are more and more places where stainless steel is used, such as pots, bowls, ladles, city sculptures, buildings, decoration rooms, etc. But people do not have a deep understanding of the discrimination of stainless steel. Some customers try to buy stainless steel kitchenware with magnets. It is considered that stainless steel is absorbed by magnets, but stainless steel is not absorbed by magnets. In fact, it is unscientific to judge the quality by magnet attraction, which indicates that people still have misunderstandings about stainless steel.

Usually iron and steel are distinguished by their carbon content. Iron-carbon alloys with less than 2% carbon content are steel, and those with more than 2% carbon content are called iron. Steel is widely used because of its toughness, elasticity and rigidity. Everything we touch in life is steel, but people call it different. For stainless steel, whether the magnet can be absorbed or not, as long as it meets the quality standards, it is stainless steel. Chromium is the main corrosion resistant element of stainless steel. Steel containing more than 10.5% chromium does not rust. Different alloying elements are added in the smelting process, so there is a difference between magnets that can be absorbed and magnets that cannot be absorbed. Stainless steel is generally divided into austenite, ferrite and martensite according to its structure.

If different proportions of chromium and nickel are added to molten steel, the austenitic steel is stainless steel that magnets cannot absorb; if chromium and a small amount of nickel (or no nickel) are added to molten steel, the steel is ferritic stainless steel that magnets absorb; the main alloying elements of martensitic stainless steel are chromium, iron and carbon. There are more than 100 kinds of stainless steel with different alloying contents, and their properties and functions are also different. Austenitic stainless steel is generally used for decoration, landscape and sculpture. Because of the low thermal conductivity of austenitic stainless steel, it is not suitable to use it as kettle, frying pan and rice cooker. It will waste energy and prolong the time of cooking with boiling water.

Using ferritic stainless steel as frying pan and rice cooker not only has excellent corrosion resistance, but also its thermal conductivity is nearly half higher than that of austenitic stainless steel. Ferritic stainless steel should be used for washing machine inner barrel, water heater and vegetable basin as long as the utensils contacted with water. Some people complain that stainless steel tools are not fast because of the wrong choice of stainless steel. Austenitic stainless steel can not be hardened and is not suitable for cutting tools and cutting tools. Tools made of martensitic stainless steel can change the hardness of stainless steel by heat treatment, such as quenching and tempering. "Stainless steel" is only a general term, the standard name is "acid-resistant and alkali-resistant steel". Stainless steel is made by adding chromium, nickel and other metal elements on the basis of ordinary steel. The higher the content of nickel, molybdenum, titanium and other metal elements, the better the quality of stainless steel. The traditional identification method is magnet absorption, the smaller the magnetism, the better the quality. Chromium stainless steel is only chromium stainless steel without nickel. Chromium-nickel stainless steel is not attracted by magnets. It is used in industrial and chemical fields. Common household appliances such as microwave ovens, rice cookers, electric water heaters and electric water bottles are all chromium stainless steel, which can be absorbed by magnets. All except austenitic stainless steel are magnetic.

Principle of magnet attraction

Depending on the characteristics of magnets, if interpreted by atomic current, it is the magnetic field produced by current that magnetizes other objects and produces the interaction of electric field and electric field to produce force. Matter is mostly made up of molecules, molecules are made up of atoms, and atoms are made up of nuclei and electrons. Within an atom, electrons spin around and around the nucleus. Both of these movements of electrons produce magnetism. But in most substances, electrons move in different directions and in disorder, and magnetic effects cancel out each other. Therefore, most substances do not exhibit magnetism under normal conditions. Ferromagnetic materials, such as iron, cobalt, nickel or ferrite, are different. The electron spins in them can be arranged spontaneously in a small range to form a spontaneous magnetization region, which is called magnetic domain. After magnetization of ferromagnetic materials, the internal magnetic domains are arranged in a neat and uniform manner, which makes the magnetism stronger and makes the magnet become a magnet. The magnet absorption process is the magnetization process of the iron block. The magnetized iron block and the magnet have attraction between different polarities, and the iron block is firmly "sticking" with the magnet. Let's say that magnets are magnetic.

Whether a magnet can absorb a thing or not depends on its permeability, and the permeability and domain are related. Among all the elements in nature, nickel has the highest permeability, followed by cobalt and iron. Other substances such as copper also have a certain permeability, but it is very low, so we can not feel it, No. All ferrous materials can be absorbed by magnets. Stainless steel belongs to alloys, that is, adding chromium and nickel on the basis of iron, such as 1Cr13, adding chromium, 310 stainless steel, Cr25Ni20Si2, adding chromium and nickel, and Si, 304 stainless steel, adding chromium, nickel and Ti, thus changing the original arrangement of magnetic domains and decreasing permeability. Low, not even in our hands, so we don't feel suction. In the same way, we can make alloys with very high permeability by alloying.

People often use magnets to adsorb stainless steel to verify its merits and demerits. No magnetic absorption, considered good, on the contrary, is considered to be counterfeit. In fact, this is an unrealistic method of discrimination. Generally speaking, people who have been engaged in stainless steel materials for more than ten years know that the traditional method of judging stainless steel by whether it has magnetism or not is likely to suffer losses. According to them, stainless steel is of various kinds.