The austenitic type is non-magnetic or weakly magnetic, and martensite or ferrite is magnetic.
The scaffolds usually used as decorative tube sheets are mostly austenitic 304 materials, which are generally 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 be considered as What is the reason for counterfeit or unqualified?
Due to component segregation or improper heat treatment during smelting, a small amount of martensite or ferrite structure in the austenite 304 scaffold will be caused. In this way, there will be weak magnetism in the 304 scaffolds.
Also, after 304 scaffoldings are cold worked, the structure will be transformed into martensite. The greater the degree of cold working deformation, the more martensite 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. Because the bending deformation is larger, the magnetic induction is more obvious, and 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 magnetism is more obvious.
To eliminate the magnetic properties of 304 sheets of 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 304 scaffolds caused by the above reasons is not at the same level as the magnetism of other materials, such as 430 and carbon steel, which means that the magnetism of 304 sheets of steel always shows weak magnetism.
This tells us that if the scaffold is weakly magnetic or not magnetic at all, it should be judged as 304 or 316 material; if it is the same as carbon steel, it shows strong magnetism, because it is judged as not 304 materials.
Post time: Aug-14-2020