STEEL FOR PRESSURE VESSEL WITH SUPERIOR UNDERCLAD CRACKING RESISTANCE

摘要

PURPOSE:To obtain a steel with superior underclad cracking resistance by adding specified percentages of C, Si, Mn, Al, N, Cu, Ni, Cr, Mo and V to Fe while satisfying a specified equation. CONSTITUTION:A steel consisting of 0.05-0.30% C, 0.01-0.60% Si, 0.20-2.00% Mn, 0.003-0.08% Al, 0.002-0.015% N, one or more among =0.50% Cu, =1.50% Ni, =0.50% Cr, =1.50% Mo and =0.20% V, and the balance Fe with inevitable impurities or further contg. 0.08% rare earth element having atomic number 57- 71 and satisfying the equation is prepared. In the equation, in case of Al/N= 1.93,[X]=Al%, and in case of Al/N=1.98,[X]=1.93N%. This steel is effective in ensuring the safety of a pressure vessel such as a nuclear reactor vessel.