Bn - auscheidungsverstärkter, ferritic heat-resistant steel with a low carbon content and high welding properties

摘要

A ferritic heat resisting steel capable of attaining an improvement of the strength and HAZ softening resistance of a material, the omission of an after-welding heat treatment, and a decrease in a power plant construction cost. The ferritic heat resisting steel contains 0.0l-0.06 % of C, 0.02-0.80 % of Si, 0.20-l.50 % of Mn, 0.50-3.00 % of Cr, 0.0l-l.50 % of Mo, 0.0l-3.50 % of W, 0.02-l.00 % of V, 0.0l-0.50 % of Nb, 0.00l-0.06 % of N, 0.0003-0.008 % of B, 0.00l-0.5 % of Ti and 0.00l-0.5 % of Zr, or one or a combination of 0.l-2.0 % of Cu, 0.l-2.0 % of Ni and 0.l-2.0 % of Co, the contents of P, S and O being limited to not more than 0.030 %, not more than 0.0l0 % and not more than 0.020 % respectively, a weight ratio of TiN to BN being l-l00 in terms of value of (TiN+ZrN %)/(BN %), an average particle diameter of BN being not more than l νm.