Many people mistakenly believe that 304 stainless steel strips are not magnetic, so they use magnet adsorption to verify their pros and cons and authenticity, but as everyone knows, this is an extremely one-sided, unrealistic and wrong identification method. Most of the stainless steel usually used for decorative tube sheets is austenitic 304 material, which is generally non-magnetic or weakly magnetic, but may also appear magnetic due to fluctuations in chemical composition or different processing conditions caused by smelting, but this cannot be considered as a Counterfeit or substandard, what is the reason for this?
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 structure in austenitic 304 stainless steel strips will be formed. . In this way, the 304 stainless steel belt will have weak magnetism.
In addition, after cold working of 304 stainless steel strip, the structure will also be transformed to martensite. The greater the cold working deformation, the more martensitic transformation, and the greater the magnetic properties of the steel. Like a batch of steel strips, Φ76 tubes are produced without obvious magnetic induction, and Φ9.5 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.
If you want to completely eliminate the magnetic properties of the 304 stainless steel strip caused by the above reasons, you can restore the stable austenite structure through high-temperature solution treatment, thereby eliminating the magnetic properties.