201 stainless steel spring wire is an austenitic stainless steel. It is low-nickel, high-manganese austenitic stainless steel.
Typical composition: 16-18% chromium, 3.5-5.5% nickel, 7.5-10% manganese, with a carbon content of ≤0.15%.
1. Its higher manganese content makes it less expensive than 304 stainless steel, but it offers lower corrosion resistance. 201 stainless steel is prone to rusting in humid or acidic environments and should be avoided in high-corrosion environments.