There are many types of materials for making stainless steel screws, and they can be divided into several categories according to the structure at room temperature: austenitic type: such as 304, 321, 316, 310, etc.; martensite or ferrite type: such as 430, 420, 410 Wait; 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 result. In this way, 304 stainless steel will have weak magnetic properties. After 304 stainless steel is cold worked, the structure will also 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 belts, Φ76 tubes are produced without obvious magnetic induction, and Φ9.5 tubes are produced. Because the bending deformation is larger, the mag