Improved ferritic-austenitic stainless steel - combines high proof stress, high corrosion resistance and excellent hot forming properties

摘要

An improved ferritic-austenitic stainless steel combines high proof stress, high corrosion resistance and excellent hot forming properties making it partic. suitable for chemical appts. and centrifuge parts. It satisfies the conditions: Ni equivalent 15 to 30, Cr equivalent 28 to 50, difference Cr equiv. -Ni, equiv. 8 to 27. The compsn. in wt% comprises C max. 0.06 pref. 0.03; Si max. 1.0; Mn max. 2.0 pref. 1.0; N max. 0.1; Ni 3.0-7.0; Cr 18.0-30.0 pref. 21.0-28.0; Cu max. 3.0 esp. 0.8-2.0; Mo 0.50-6.0 pref. 2.0-4.0; B 0.0008-0.008 pref. 0.001-0.006; and =1 of the following Nb 0.08-1.2 pref. 0.08-0.50; Ti 0.05-0.8 pref. 0.1-0.5; Ta 0.1-2.0 pref. 0.1-0.5; Zr 0.03-0.5; Al 0.05-1.5; remainder Fe. The Ni equivalent = 40 (C% + Ni%) + 3 (Ni%) + (Cu%) + 2 (Mg%) and the Cr equivalent = Cr% + 5.2 (Si%) + 4.2 (Mo%) + 4.5 (Nb%) + 7.0 (Ti%) + 3.0 (Ta%) + 13.0 (Zr%) + 2.0 (Al%).