Non-magnetic steel is also called Non-magnetizable steels. A large amount of alloying elements such as nickel, manganese, chromium, and copper are added to the steel. Typical non-magnetic steel includes 25% Ni steel and high manganese containing Mn12-18%. Non-magnetic steel, such as 14Mn series, 18Mn series and 25Mn series, as well as 18Cr-8Ni series austenitic stainless steel and Ni-C; Cr-Mn series austenitic steel, etc. As a new material of non-magnetic steel, high manganese austenitic steel has excellent performance to reduce the austenite transformation point A3 to below normal temperature. Non-magnetic steel belongs to Fe-Mn-Al-C series austenite, chemical composition determines electromagnetic properties, stable structure, excellent mechanical properties, low magnetic permeability and high resistivity, and eddy current loss in the magnetic field is extremely small. When the magnetic field strength is 16000A/m (200 Oersted), the magnetic permeability of non-magnetic steel μ≤1.319×10-6H/m (1.05 high/Ao) The magnetic permeability of stainless steel μ=1.339×10-6H/ m (1.1 high/o). Austenitic stainless steels are mildly magnetic when cold worked. The magnetic permeability μ≤1.319×10-6 h/m is required, and it is widely used in large and medium-sized transformers, electromagnets, and other non-magnetic structural materials.