Patent ID: 6254697
Filing Date: 2001-07-03
Classification: C21D,C22C

Abstract:
A cast steel material for pressure vessels which contains, on a weight percentage basis, 0.04 to 0.1% C, 0.1 to 0.4% Si, greater than 0% and up to 0.2% Mn, 0.1 to 0.8% Ni, 3 to 4.5% Cr, 0.2 to less than 0.5% Mo, 0.2 to 0.4% V, 0.5 to 2% W, 0.01 to 0.06% Nb and/or Ta, 0.001 to 0.01% B, 0.005 to 0.045% Ti, 0.006 to 0.015% Al, greater than 0.005% and less than 0.01% N, 1 to 0.008% O, 0 to 0.015% P as an impurity, and 0 to 0.007% S as an impurity, the balance being Fe and incidental impurities, provided that the aforesaid contents of Ti, Al, O and N satisfies the following relationship:N-0.29{Ti-1.5(O-0.89Al )}.ltoreq.0.0060%.