Martensitic precipitation hardening stainless steels have a predominantly austenitic structure at annealing temperatures of around 1040 to 1065°C. They can change from austenite to martensitic stainless steel after being cooled to room temperature.
SUS630 steel bears the properties of good corrosion resistance and oxidation resistance and machinability, which is similar to stainless steel series 304 in annealed condition. It should be taken into consideration that the cold working of stainless steel SUS630 or X5CrNiCuNb17-4 is only under the fully annealed condition.
This kind of Martensitic precipitation-hardening stainless steel is mainly used in making high-intensity parts requiring not only rust resistance but also weak acid, alkali and salt resistance, such as last-stage moving blade of steam turbine, structural parts working in corrosive environment below 300℃, etc.
