People often think that magnets absorb stainless steel pipes to verify their quality and authenticity. They are not attractive and non-magnetic. They are considered to be good and genuine; if they are magnetic, they are considered to be counterfeit products. In fact, this is an extremely one-sided and impractical method of identifying errors. There are many types of stainless steel pipe fittings, which can be divided into several categories according to the structure at room temperature: 1. Austenite type: such as 304, 321, 316, 310; 2. Martensite or ferrite type: such as 430, 420, 410; Austenitic type is non-magnetic or weakly magnetic, and martensite or ferrite is magnetic.
The stainless steel decorative tubes usually used as decorative tube sheets are mostly austenitic 304 materials. Generally speaking, they are non-magnetic or weakly magnetic. However, due to chemical composition fluctuations or different processing conditions caused by smelting, magnetic properties may also appear, but this cannot Think it is fake 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 a small amount of martensite or Ferrite organization. In this way, the 304 stainless steel decorative tube will have weak magnetism. In addition, the 304 stainless steel decorative tube undergoes cold processing, the structure will also be transformed into martensite. The greater the degree of cold working deformation, the greater the transformation of martensite and the greater the magnetic properties of the steel. Like a batch of steel belts, Φ76 tubes are produced without obvious magnetic induction, and Φ9.5 tubes are produced. Because the bending deformation is larger, the magnetic induction is more obvious, and the deformation of the square rectangular tube produced is larger than that of the round tube, especially the corner part, the deformation is more intense and the magnetism is more obvious. In order to completely eliminate the magnetic properties of 304 steel caused by the above reasons, the austenite structure can be restored and stabilized by high temperature solution treatment, thereby eliminating the magnetic properties. In particular, the magnetism of the 304 stainless steel decorative tube caused by the above reasons is not at the same level as the magnetism of other stainless steel decorative tubes, such as 430 and carbon steel. That is to say, the magnetism of 304 steel is always weakly magnetic.