| 摘要 |
PURPOSE:To suppress reduction of the amt. of austenite in the weld heat-affected zone of a steel as a base metal and the weld zone formed with no filler metal by specifying the ratio of the Cr equiv. to the Ni equiv. of the steel having a specified compsn. and by considerably increasing the amt. of N and the total amt. of all the alloying elements except C and Si. CONSTITUTION:The compsn. of a steel is composed of, by weight, <=0.025% C, 0.01-0.2% Si, 1.0-5.0% Mn, 28-35% Cr, 6-16% Ni, 3.1-6.0% Mo, 0.2-0.4% N and the balance Fe. The ratio of the Cr equiv. represented by formula I to the Ni equiv. represented by formula II is regulated to 1.9-2.4 and the total amt. of all the alloying elements except C and Si is regulated to >=45%. 0.1-3.0% Cu may be added to the compsn. so as to regulate the ratio of the Cr equiv. represented by the formula I to the Ni equiv. represented by formula III to 1.9-2.4 and the total amt. of all the alloying elements except C and Si to >=45%. The steel has high corrosion resistance and ensures extremely superior corrosion resistance for the weld heat-affected zone or the weld zone formed with no filler metal.
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