A cast low carbon stainless steel for use in nitric acid at higher concentrations and temperatures

摘要

AbstractThis paper introduces three modifications of cast, low carbon stainless steels with about 15 to 20 Cr, 13 Ni and 4.5 to 6.5 Si which can be used for pumps and valves in nitric acid plants. Mechanical and structural properties, castability, machinability and weldability are discussed to characterize the practical applicability of these alloys for producers and users of such cast components. Laboratory corrosion tests in boiling nitric acid between 50 and 98 wt prove the superior resistance of the Si‐bearing alloys in the 90 and 98 acid compared to standard CrNi‐steels without Si. Comparative field tests with cast pump impellers and casings confirm the very good corrosion resistance of the Si‐bearing alloys in highly concentrated nitric acid under service condi