抄録
New 18-8 high strength austenitic stainless steel with 0.1%P-0.2%Ti-0.2%Nb for super-heater and re-heater tubes in ultra-super critical power plants has been developed using the precipitation hardening of fine intragranular precipitates such as globular M23C6 carbides, MC type carbides and needle like FeTiP distributed inside grain. The solidification cracking susceptibility of the new 18-8 heat resistance steel was investigated by varying the Creq/Nieq and phosphorus amount. It was clarified that the solidification cracking susceptibility of new 18-8 heat resistance steel decreased by increasing Creq/Nieq to increase the amount of δ ferrite crystallization and promote the progress of welding solidification by (Nb,Ti)C crystallization in terms of microsegregation behavior using the numerical model.
