BN PRECIPITATION STRENGTHENED TYPE LOW CARBON FERRITIC HEAT RESISTANTE STEEL EXCELLENT IN WELDABILITY

摘要

PROBLEM TO BE SOLVED: To provide a ferritic heat resistant steel capable of attaining the improvement of the strength of the material, the improvement of HAZ softening property, the elimination of heat treatment after welding and the reduction in the cost of power generating equipment construction. ;SOLUTION: This steel is the one having a compsn. contg. 0.01 to 0.06% C, 0.02 to 0.80% Si, 0.20 to 1.50% Mn, 0.50 to 3.00% Cr, 0.01 to 0.50% Mo, 0.01 to 3.50% W, 0.02 to 1.00% V, 0.01 to 0.50% Mb, 0.001 to 0.06% N, 0.0003 to 0.008% B, 0.001 to 0.5% Ti and 0.001 to 0.5% Zr, or contg. 0.1 to 2.0% Cu, 0.1 to 2.0% Ni and 0.1 to 2.0% Co alone or in combination, in which the content of P is made to ≤0.030%, that of S to ≤0.010% and that of 0 to ≤0.020%, and the weight ratio of TiN and BN present in the steel is made to 1 to 100 as the value of (TiN+ZrN%)/(BN%).;COPYRIGHT: (C)1999,JPO