Duplex stainless steels combine the merits of austenitic stainless steels, which are ductile and have excellent corrosion resistance, and ferritic stainless steels, which are resistant to stress corrosion cracking. Among these, super duplex stainless steels refer to those which are particularly strong and corrosion resistant, and whose pitting resistance equivalent (PRE) values are more than 40. Due to their corrosion resistance and durability, they are used for parts that are to be directly exposed to corrosive substances such as chemical substances and seawater.