Corrosion resistant duplex stainless steel with improved galling resistance

摘要

A duplex stainless steel having a good combination of galling resistance and corrosion resistance is disclosed containing in weight percent about: -Broad Intermediate Preferred -C 0.1 Max. 0.05 Max. 0.025 Max. -Mn 0-6 1-4 1-3 -Si 2.5-6 3-6 4-5 -Cr 16-24 17-22 18-21 -Ni 2-12 6-10 7-9 -Mo 4 Max. 0.5-3 1.0-2 -N 0.07-0.30 0.10-0.25 0.15-0.20 - and the balance of the alloy is essentially iron. In the annealed condition the alloy is limited to about 15-50% v/o ferrite. To attain its good galling resistance, the alloying elements are balanced so that the % Ni+0.68 (% Cr)+0.55 (% Mn)+0.45 (% Si)+(% C+% N)+% Mo+0.2 (% Co), is at least about 27.5, and the Ni/Si ratio is not more than about 2.5.