Corrosion the X2CrNiMoN25-7-4 Super Duplex Stainless Steel in 65% Nitric Acid at Boiling Temperature

Abstract. Corrosion of corrosion-resistant steels is a natural phenomenon, but knowing its speed allows you to determine the durability of a structural element. The corrosion rate may depend on the surface condition, which is shaped during the manufacturing process. Thin steels are produced by cold forming, while thick steels are produced by hot forming. Therefore, they have a surface layer with different mechanical, physical and chemical properties. The paper discusses the issue of determining the corrosion rate for cold-rolled and hot-rolled steel. The tests were carried out on samples taken from sheets in the delivered condition. The samples were soaked in 65% nitric acid at boiling point. As a result of the research, it was found that steel produced in the cold rolling process has greater corrosion resistance, especially in the first period of corrosion. This is most likely due to the surface strengthening of the material as a result of cold forming.