40Mn18Cr3 is non-magnetic austenitic manganese-chromium steel retaining ring, after solution heat treatment, semi-hot or cold deformation strengthening deformation enhanced to increase the strength of steel to meet the needs of different types retaining ring. Retaining ring type for class Ⅰ ~ Ⅲ the turbo-generator non-magnetic retaining ring forgings and other requirements of non-magnetic components.