High-strength ferritic heat-resistant steel and method of producing the same

摘要

PCT No. PCT/JP95/02247 Sec. 371 Date Jul. 22, 1996 Sec. 102(e) Date Jul. 22, 1996 PCT Filed Nov. 2, 1995 PCT Pub. No. WO96/14443 PCT Pub. Date May 17, 1996This invention provides a ferritic heat-resistant steel having excellent HAZ softening resistance characteristics and exhibiting a high creep strength up to a high temperature of not lower than 500 DEG C., and a method of producing such a steel, the steel comprising in terms of mass %, 0.01 to 0.30% of C, 0.02 to 0.80% of Si, 0.20 to 1.50% of Mn, 0.50 to 5.00% of Cr, 0.01 to 1.50% of Mo, 0.01 to 3.50% of W, 0.02 to 1.00% of V, 0.01 to 0.50% of Nb, 0.001 to 0.06% of N, one or both of 0.001 to 0.8% of Ti and 0.001 to 0.8% of Zr, wherein a value (Ti+Zr) in (Cr, Fe, Ti, Zr) of a M23C6 type carbide in the steel is 5 to 65%, and the present invention provides a method of producing the same.