| 摘要 |
PURPOSE:To improve the toughness of a high Cr ferritic steel having a specified compsn. as well as to maintain the strength and corrosion resistance by adding a specified amt. of Ti and specifying the amt. of Mo+1/2W. CONSTITUTION:This heat resistant high Cr steel consists of, by weight, 0.06-0.15% C, <=0.50% Si, 6.0-13.5% Cr, 0.35-0.85% Mo, <=0.90% W (Mo+1/2W=0.80-1.30%), 0.15-0.30% V, 0.01-0.10% Nb, 0.001-0.1% Ti and the balance Fe. In the steel, >=6.0% Cr is required to ensure corrosion and oxidation resistance but >13.5% Cr remarkably reduced the toughness and long-time creep strength. Mo and W contribute toward improving the strength at high temp. and a significant effect is produced by adding Mo and W in combination, but the effect is not satisfactory in case of Mo+1/2W<0.80% and is not further enhanced in case of Mo+1/2W>1.3%. Though Ti contributes toward making the steel structure fine and improving the toughness, <0.001% Ti does not produce the satisfactory effect and >0.1% Ti remarkably reduces the strength at high temp.
|
