Hits:Updated:2018-10-24 16:10:55【Print】
Why is stainless steel magnetized?
It is widely believed that magnets attract stainless steel strips, verifying their strengths and weaknesses, and verifying their authenticity. This suction cup is magnetic and is considered to be fake. In fact, this is an extremely one-sided and unrealistic method of misidentification.
There are many types of stainless steel, which can be divided into several types according to the structure at room temperature:
1, the size of austenite: 304, 321, 316, 310, and so on.
2, martensite or iron body: such as 430, 420, 410, and so on.
Austenite is magnetic or weak, and martensite or ferrite is magnetic.
Usually used as decorative tube sheet, mainly 304 stainless steel material, generally non-magnetic or weak magnetic, but due to magnetic fluctuations or processing state caused by smelting chemical composition may also have different magnetic fluctuations or processing state, but can not be considered as fake and shoddy ,What is the reason?
Above austenite, it is non-magnetic or weakly magnetic, martensite and ferrite are magnetic, and can cause a small amount in austenitic stainless steel 304 or iron body structure due to improper smelting component isolation or heat treatment. Martensite. Thus, 304 stainless steel will have weak magnetic properties.
In addition, after cold treatment, 304 stainless steel will be transformed into martensite, and the more deformation of martensite, the greater the magnetic properties of steel. As many steel bars, 76 tubes are produced, no obvious magnetic induction, and 9.5 tubes are produced. Since the magnetic deformation of the bending deformation is more obvious, since the deformation amount is larger than the deformation amount of the circular tube, especially the curved portion, the deformation is stronger and the magnetic property is more remarkable.
In order to completely eliminate the magnetic properties of the 304 steel caused by the above reasons, the stability of the austenite structure can be restored by the high temperature solution treatment, thereby eliminating the magnetic properties.
In particular, for the above reasons, the 304 stainless steel magnetic material and other stainless steel materials, such as 430, carbon steel, are completely different in magnetic properties, that is, the 304 magnetic force always shows weak magnetic steel.
This tells us that if stainless steel is weakly magnetic or completely non-magnetic, it should be classified as 304 or 316 materials. If the magnetism is the same as carbon steel, it shows strong magnetic properties because it is not a 304 material.
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