martensitic-ferritic stainless steel, manufactured product, process for producing forged or rolled bars or parts of martensitic-ferritic stainless steel and process for producing all seamless martensitic-ferritic stainless steel

摘要

martensitic-ferritic stainless steel, manufactured product, process for the production of forged or rolled bars or parts of martensitic-ferritic stainless steel and process for the production of seamless pipe of martensitic-ferritic stainless steel. The present invention relates to a high corrosion resistance martensitic ferritic stainless steel comprising the following chemical composition: c: from 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 ° / mass), balanced by Fe and inevitable industrial process impurities at acceptable levels. furthermore, the martensitic ferritic stainless steel of the present invention has a localized corrosion parameter (pcl) between 3.2 and 6.2, defined by the equation below: pcl = 0.500% cr + 1.287. % mo + 1,308. % n - 5,984. The present invention also relates to a manufactured product comprising the ferritic-ferritic stainless steel of the invention; a process for the production of forged or rolled handles or bars; and to a process for producing seamless pipe of this type of martensitic ferritic stainless steel of the present invention, wherein the processes of the invention have a determined step heating temperature that follows the following equation: tproc - 16.9 *% cr -49.9 *% mo 535.