| 摘要 |
PROBLEM TO BE SOLVED: To provide heat resistant low alloy ferritic steel which has reduced in creep strength reduction in a weld-heat affected zone. SOLUTION: The heat resistant low alloy ferritic steel has a composition comprising, by mass, 0.001 to <0.05% C,≤1.0% Si,≤2.0% Mn,≤0.030% P,≤0.015% S, 0.2 to <7% Cr, 0.05 to 0.40% V, 0.01 to 0.10% Nb, 0.001 to <0.045% N,≤0.010% sol.Al, and≤0.010% O (oxygen), and the balance Fe with impurities, and in which the precipitation density of carbides and carbonitrides having particle diameters of≥0.3μm is≤1×10<SP>6</SP>pieces/mm<SP>2</SP>. The steel can contain one or more kinds selected from Mo, W, Cu, Ni, Co, Ta, Hf, Nd, Ti, Ca, Mg, and B. COPYRIGHT: (C)2003,JPO
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