The rust steel material is divided into austenite, martensite and ferrite, the austenite type is non-magnetic or weakly magnetic, the martensite or ferrite is magnetic. The stainless steel is mostly austenitic. 304 316 material, generally speaking, is non-magnetic or weak magnetic, but due to chemical composition fluctuations or processing conditions may also occur due to smelting, people often think that magnets adsorb stainless steel, verify its pros and cons and authenticity, Do not suck non-magnetic, think it is good, the goods are genuine; if the sucker is magnetic, it is considered a counterfeit fake. In fact, this is a one-sided identification method. It is mentioned above that austenite is non-magnetic or weakly magnetic, while martensite or ferrite is magnetic. A small amount of martensite or ferrite in austenitic stainless steel is caused by segregation or heat treatment of components during smelting. organization. This way the stainless steel will have a weak magnetic properties. In addition, the stainless steel is cold-worked, and the microstructure is also transformed into martensite. The greater the cold work deformation, the more martensite transformation and the greater the magnetic properties of the steel. In order to completely eliminate the magnetic properties caused by the above reasons, the high-temperature solution treatment can be used to restore the stable austenite structure, thereby eliminating magnetic properties. In particular, the magnetic properties of stainless steel due to the above reasons are not at the same level as the magnetic properties of other materials such as 430 and carbon steel. The magnetic strength of SUS304M is about 1.6u-2.0u; the magnetic properties of SUS304HC are 1.01u-2.0u or so; SUS316 has a magnetic strength of less than 1.01u. Therefore, the quality of light products with magnets feels more magnetic, on the contrary, the quality of the product is not obvious.
This tells us that austenitic stainless steel standard fasteners are usually non-magnetic, but some of the magnetic properties may be obvious after cold working. The magnetic properties of various materials are also applicable to stainless steel, only in vacuum state. It is possible that it will be completely non-magnetic.
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