People often use magnets to attract stainless steel hose clamps to verify their pros and cons and their authenticity. If they do not attract and have no magnetism, they think they are good and genuine; those who attract magnets are considered counterfeit. In fact, this is an extremely one-sided, unrealistic and wrong identification method. There are many kinds of stainless steel, which can be divided into several categories according to the structure at room temperature: austenite type is non-magnetic or weak magnetic, martensite or ferrite is magnetic. Most of the stainless steels usually used as decorative tube sheets are austenitic 304 materials, which are generally non-magnetic or weakly magnetic.

However, magnetism may also appear due to chemical composition fluctuations or different processing states caused by smelting, but this cannot be considered counterfeit or unqualified. What is the reason? As mentioned above, austenite is non-magnetic or weakly magnetic, while martensite or ferrite is magnetic. Due to component segregation or improper heat treatment during smelting, a small amount of martensite or ferrite in austenitic 304 stainless steel will be caused. body tissue. In this way, 304 stainless steel will have weak magnetism.

In addition, after cold working of 304 stainless steel, the structure will also be transformed into martensite. The greater the cold working deformation, the more martensite transformation, and the greater the magnetic properties of the steel. Like a batch of steel strips, 76 tubes are produced without obvious magnetic induction, and 95 tubes are produced. The magnetic induction is more obvious due to the large deformation of the bending and bending. The deformation of the square rectangular tube is larger than that of the round tube, especially the corner part, the deformation is more intense and the magnetic force is more obvious.

In order to completely eliminate the magnetic properties of 304 stainless steel caused by the above reasons, the stable austenite structure can be restored by high-temperature solution treatment, thereby eliminating the magnetic properties. In particular, the magnetic properties of stainless steel caused by the above reasons are completely different from those of other materials such as carbon steel, which means that the magnetic properties of 304 steel always show weak magnetic properties. This tells us that if the stainless steel belt is weakly magnetic or completely non-magnetic, it should be judged as 304 or 316 material;