HEAT RESISTANT CAST STEEL, A MANUFACTURING METHOD OF THE HEAT RESISTANT CAST STEEL, CASTING PARTS OF A STEAM TURBINE AND A MANUFACTURING METHOD OF THE CASTING PARTS OF THE STEAM TURBINE IN WHICH THE RATIONALIZATION OF MO CONTENT, B CONTENT, AND CR CONTENT ARE ATTEMPTED

摘要

PURPOSE: A heat resistant cast steel, a manufacturing method of the heat resistant cast steel, casting parts of a steam turbine and a manufacturing method of the casting parts of the steam turbine are provided to enhance a creep rupture ductility or toughness and extend a long time creep rupture life because the rationalization of Mo content, B content, and Cr content are attempted.;CONSTITUTION: A heat resistant cast steel comprises 0.05 to 0.15Wt% of C, 0.03 to 0.2Wt% of Si, 0.1 to 1.5Wt% of Mn, 0.1 to 1Wt% of Ni, 8 to 10.5Wt% of Cr, 0.2 to 1.5Wt% of Mo and 0.1 to 0.3v of V, 0.1 to 5Wt% of Co, 0.1 to 5Wt% of Co, 0.005 to 0.03Wt% of N, 0.01 to 0.2Wt% of Nb, 0.002 to 0.015Wt% of B, 0.01 to 0.1Wt% of Ti. A remnant unit comprises Fe and inevitable impurities. The heat resistant cast steel comprises at least one kind among 0.01 to 0.2Wt% of Ta, 0.01 to 0.1Wt% of Zr and 0.01 to 1.5Wt% of Re. A casting part of a steam turbine comprises at least a predetermined portion being manufactured by using heat resistance cast steel.;COPYRIGHT KIPO 2012