One of the key differences between super duplex 2507 and duplex 2205 round bar is their composition. Both materials are duplex stainless steel alloys, but super duplex 2507 bars contain more chromium, nickel, and molybdenum, making them more corrosion-resistant than 2205. Additionally, super duplex 2507 rods have better strength & toughness than 2205, making it a preferred choice for high-stress applications.