Nitrogen in combination with molybdenum helps in localized corrosion resistance as well as increases strength, it also helps in delaying carbide precipitation during sigma phase. Nitrogen along with carbon provides creep rupture strength. When compared to 300-series alloys like 321H, 310S, 304H, the grade 253 shows higher strength to resist creep. The 300-series alloy’s creep rupture strength varies with temperature while the grade 253 remains constant in strength.
The grade can be readily used in thermally active environments with a longer service life. The ductility and the forming characteristics of the grade 253 also prove to be lucrative. These features attract many applications for the grade. Thinner sections requiring adequate strength can be suitably manufactured using this grade. The grade can be hot and cold formed. Pertaining to the nitrogen content and the mechanical strength, large forces are required for the grade to form.
The grade due to its high strength is used in respective structural as well as pressure bearing applications. Its strength is exceptionally retained at higher temperatures and hence, the grade is readily selected for applications in the temperature range of 500-950°C. The alloy also has convenient aqueous corrosion resistance. During sigma phase, the grade might face a slight sensitization but the strength is restored with a little loss of aqueous corrosion resistance. An excellent performance of the grade is achieved under environments with iso-thermal, cyclic oxidation, flue gases, combustion gases, and carburizing conditions. With the addition of nitrogen and adequate amount of carbon, the grade is less prone to sigma phase embrittlement. It exceptionally retains its structural stability.