Joint alloying of 0.85 to 1.1 mass% C + N raises the strength and cold work hardening of steels with 18 to 19 mass% Cr and Mn each and allows to produce them at atmospheric pressure. A yield strength of 600 MPa is combined with a true fracture stress of almost 2500 MPa and ≈ 70 % elongation. However, there is a risk of carbide/nitride precipitation during quenching of thicker cross sections after solution annealing. The addition of Mo and Cu affects the corrosion resistance as well as the precipitation. Submersion test and current density/potential tests in several aqueous solutions characterize the corrosion behaviour. Tests on intercrystalline corrosion are used to detect the precipitation as a function of quenching rate. It is shown that the C/N ratio is of key importance in improving the properties.