MARTENSITIC-FERRITIC STAINLESS STEEL, MANUFACTURED PRODUCT AND PROCESSES USING THE SAME

摘要

The present invention relates to a martensitic-ferritic stainless steel with high corrosion resistance that comprises the following chemical composition: C: from 5 0.005 to 0.030%; Si: from 0.10 to 0.40%; Mn from 0.20 to 0.80%; P: 0.020% max; S: 0.005% max; Cr: from 13 to 15%; Ni: from 4.0 to 6.0%; Mo: from 2.0 to 4.5%; V: from 0.01 to 0.10%; Nb: from 0.01 to 0.50%; N: from 0.001 to 0.070%; Al: from 0.001 to 0.060%; Ti: from 0.001 to 0.050%; Cu: from 0.01 to 1.50%; O: 0.005% max (all in weight percent), wherein the balance is performed by Fe and unavoidable impurities 10 from the industrial possessing in acceptable levels. Additionally, the martensitic- ferritic stainless steel of the present invention has the localized corrosion parameter (LCP), between 3.2 and 6.2, as defined by equation below; LCP = 0.500-%Cr + 1.287 · %Mo + 1.308·%N 5.984 The present invention also relates to a manufactured product comprising the martensitic-ferritic stainless steel of the invention; to a process for 15 production of forged or rolled parts or bars; and to a process for production of seamless tube from this martensitic-ferritic stainless steel of the present invention, wherein the processes of the invention have a heating temperature in determined step following the equation below: T Proc - 16.9 * %Cr -49.9 *%Mo > 535