| 摘要 |
PURPOSE:To improve corrosion resistance in a weld zone of a structure manufactured by the use of undermentioned steel, by specifying the relationship between Cr equivalent and Ni equivalent as well as the relationship between N% and Ni% in a two-phase stainless steel having a specific composition. CONSTITUTION:The structural two-phase stainless steel has a composition which consists of, by weight, <=0.03% C, <=1.5% Si, <=2.0% Mn, 18.0-30.0% Cr, 5.0-12.0% Ni, 1.5-5.0% Mo, 0.10-0.30% N, and the balance Fe with inevitable impurities and in which the relationship between N% and Ni% and the F value obtained by subtracting Ni equivalent (represented by equation III) from Cr equivalent (represented by equation II) are regulated to a range represented by inequality I and 12.0-16.0, respectively. By satisfying the above conditions, a weld zone excellent in pitting resistance, crevice corrosion resistance, and intergranular corrosion resistance can be obtained. If necessary, 0.1-1.0% Cu and 0.02-0.10% Sn are added to the above steel composition.
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