a high strength non - magnetic stainless steel comprising , by weight ratio , less than 0 . 20 % c , less than 1 . 00 % si , 14 - 16 % mn , less than 0 . 005 % s , 0 . 2 - 1 . 0 % ni , 15 - 19 % cr , 0 . 30 - 0 . 40 % n , and fe and other impurity elements , of which c + n constitutes 0 . 40 - 0 . 55 % and the mn equivalent equals 30 - 33 . the stainless steel has a hardness more than hv 500 , a magnetic permeability less than 1 . 01 after drawing , the steel may be suitably used as the steel for the micro shafts of video tape recorders and electromagnetic valves .