Process for the production of austenitic stainless steel strips and austenitic stainless steel strips so obtainable having good weldability as cast and use thereof for the production of welded products

摘要

A process for the production of austenitic stainless steel strips having as case a good weldability, comprising the operations of: solidification in a mold of a continuous casting apparatus with twin counterrotatng rolls, a strip having a thickness comprised between 1 to 5 mm and having the following composition in percent by weight: Cr 17-20; Ni 6-11; c0.04; n0.04; s0.01; Mn1.5; Si1.0; Mo 0-3; Al0.03; and possibly, Ti, Nb, Ta so that: Ti+0.5(Nb+Ta)6C-3S with proviso that Ti6S, or NB+Ta1C with the proviso that TI6S; being in any case Nb+Ti+Ta1.0; the remaining part being substantially Fe with a delta-ferrite volume percentage comprised between 4 and 10% calculated with the formula: delta-ferrite=(Creq/Nieq-0.728)x500/3 wherein: Creq/Nieq=[Cr+Mo+1.5Si+)0.5Nb+0.25Ta+2.5(Al+Ti)+18]/[Ni+30(C+N)+0.5Mn+36]; and, possibly, heating the strip at a temperature between 900 to 1200° C. for a period of time less than 5 minutes. Subject of the invention is also the stainless steel strip obtained with the process and the use thereof for manufactured welded products, i.e. welded tubes.