FERRITE HEAT-RESISTANT CAST STEEL HAVING EXCELLENT NORMAL-TEMPERATURE TOUGHNESS AND EXHAUST SYSTEM COMPONENT FORMED FROM THE SAME

摘要

A heat-resistant, ferritic cast steel having excellent room-temperature toughness, which has a composition comprising by mass 0.32-0.48% of C, 0.85% or less of Si, 2% or less of Mn, 1.5% or less ofNi, 16-19.8% of Cr, 3.2-5% ofNb, Nb/C being 9-11.5, 0.15% or less ofN, 0.002-0.2% of S, and 0.8% or less in total of W and/or Mo, the balance being Fe and inevitable impurities, and a structure in which a eutectic (´ + NbC) phase formed from a ´ phase and Nb carbide (NbC) has an area ratio of 60-90%, and an exhaust member made thereof.