There are different grades of Duplex Plate available in the market. The grades are governed by different standards and each different grade has its specifications. The mechanical properties of each grade vary as well. The grade is also specified by a number assigned to each grade. The decisive factor is the quantity of chromium in the composition. In addition to chromium there are other elements such as molybdenum and nitrogen in the composition as well. The different grades of the duplex plate could be categorized under three major categories. The first one is the standard duplex steel. This is the most used of grades. It has the grade EN1.4410. This grade is also called the 2205 and it contains average mechanical properties of all the grades of duplex steel.

And this is the most used of all grades as well. Due to the mid-range mechanical properties, this grade could be used interchangeably with other grades when necessary and the application requirements permit. The grading involves a number called the PREN number which indicates the percentage of chromium in the material. The standard duplex has PREN 28 through 38; meaning, the chromium content in the composition can range from 28% to 38%. The duplex steel plate super grades have the PREN number ranging from 38-45. The lean duplex has PREN of 22-27. The super duplex grade is preferred in applications where strength is the primary concern. Construction sites use this grade. Since the duplex 2205 sheet is made of standard duplex material, the prices are lower compared to the other duplex grades.