Materials Science Forum, Vol.475-479, 2527-2532, 2005
Centrifugal casting practice and microstructure and mechanical properties of a 2205 duplex stainless steel
Microstructural features, mechanical properties, and corrosion properties of a SAF2205 duplex stainless steel (DSS) were systematically investigated as functions of cooling rate during casting and heat treatment conditions. The choice of a duplex stainless steel was a SAF2205 alloy, of which composition is 0.03C, 21 similar to 23Cr, 4.5 similar to 6.5Ni, 2.5 similar to 3.5Mo, 0.08 similar to 0.2N, 1.0Si, and 2.0Mn with remaining Fe. A 5-stepped sand mold and the permanent Y-block mold were used to check the effect of cooling rate during solidification. The microstructural characteristics, such as grain size, the delta/gamma ratio, the existence of the carbides and sigma phase has been noticed to greatly change with the variation of cooling rate during the casting procedure. Various heat treatment conditions were also examined to achieve the optimized mechanical properties of DSS. Based on the preliminary examination, the feasibility study of utilization of centrifugal casting has been carried out for the production of better quality DSS pipe components. Melting and casting practices of DSS during centrifugal casting in an air atmosphere were systematically investigated in order to obtain the optimized process parameters.
Keywords:centrifugal casting;2205 duplex stainless steel;microstructure;delta/gamma ratio;mechanical properties;cooling rate