Abstract: The present disclosure relates to the use of a duplex stainless steel as heat exchanger material in a phosphoric acid production system using the wet method. The steel has the following composition in percent by weight: C max 0.03 Si max 0.5 Mn max 3 Cr 26-29 Ni 4.9-10 Mo 3-5 N 0.35-0.5 B max 0.0030 Co max 3.5 W max 3 Cu max 2 Ru max 0.3 balance Fe and normal occurring impurities.

Abstract: A method of providing corrosion resistance, structural stability, mechanical strength and workability in applications with aggressive environments such as chloride-containing environments, are realized by providing at least one article formed from a composition which includes (in weight- %) up to 0.03% C, up to 0.5% Si, 24.0-30.0% Cr, 4.9-10.0% Ni, 3.0-5.0% Mo, 0.28-0.5% N, 0-3.0% Mn, 0-0.0030% B, up to 0.010%, 0-0.03% Al, 0-0.010% Ca, 0-3.0% W, 0-2.0% Cu, 0-3.5% Co, 0-0.3% Ru, balance Fe and inevitable impurities. The ferrite content is 40 to 65 volume % and a PRE number of at least between 46 and 50 in both the austenite and ferrite phase, and with an optimum ratio or relationship between PRE austenite and PRE ferrite in the range of 0.90 to 1.15; preferably between 0.9 and 1.05.

Abstract: A duplex stainless steel alloy with ferritic-austenitic matrix and with high resistance to corrosion in combination with good structural stability and hot workability, with a content of ferrite of 40-65% and a well balanced composition that imparts corrosion resistance properties, which makes it is more suitable for use in chloride-containing environments than earlier been considered being possible. The total PRE or PREW number exceeds 44. The ratio of PRE(W) value for the austenite phase to PRE(W) value for the ferrite phase lies between 0.90 and 1.15. One preferred composition includes (in weight %) up to 0.03% C, up to 0.5% Si, 24.0-30.0% Cr, 4.9-10.0% Ni, 3.0-5.0% Mo, 0.28-0.5% N, 0-3.0% Mn, 0-0.0030% B, up to 0.010%, 0-0.03% Al, 0-0.010% Ca, 0-3.0% W, 0-2.0% Cu, 0-3.5% Co, 0-0.3% Ru, balance Fe and inevitable impurities.

Abstract: A composition and method for the manufacture of products of a precipitation hardenable martensitic stainless steel, the composition of which comprises at least 0.5% by weight of Cr and at least 0.5% by weight of Mo wherein the sum of Cr, Ni and Fe exceeds 50%. The method steps include smelting the material into a casting, hot extrusion followed by a number of cold deforming steps so as to obtain at least 50% martensite and finally an ageing treatment at 425-525° C. to obtain precipitation of quasicrystalline particles. Such material can be used in vehicle components where demands for corrosion resistance, high strength and good toughness are to be satisfied.