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1. (WO1999006602) AUSTENITIC STAINLESS STEEL STRIPS HAVING GOOD WELDABILITY AS CAST

Pub. No.:    WO/1999/006602    International Application No.:    PCT/IT1998/000223
Publication Date: Feb 11, 1999 International Filing Date: Jul 31, 1998
IPC: C21D 6/00
C21D 8/02
Applicants: ACCIAI SPECIALI TERNI S.P.A.
VOEST-ALPINE INDUSTRIEANLAGENBAU GMBH
BARTERI, Massimo
PORCU, Giorgio
MASCANZONI, Antonio
Inventors: BARTERI, Massimo
PORCU, Giorgio
MASCANZONI, Antonio
Title: AUSTENITIC STAINLESS STEEL STRIPS HAVING GOOD WELDABILITY AS CAST
Abstract:
A process for the production of austenitic stainless steel strips having as cast a good weldability, comprising the operations of: solidification, in a mould of a continuous casting apparatus with twin counterrotating 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; c < 0.04; n < 0.04; s < 0.01; Mn < 1.5; Si < 1.0; Mo 0-3; Al < 0.03; and possibly, Ti, Nb, Ta so that: Ti + 0.5(Nb + Ta) > 6C-3S with proviso that Ti > 6S, or Nb + Ta > 12C with the proviso that Ti < 6S; being in any case Nb + Ti + Ta < 1.0 %; the remaining part being substantially Fe with a δ-ferrite volume percentage comprised between 4 and 10 % calculated with the formula: δ-ferrite = (Creq/Nieq - 0.728) x 500/3 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.