Outokumpu has recently developed the grade Supra 316plus (EN 1.4420, UNS S 31655), a new austenitic stainless steel grade with enhanced properties; high corrosion resistance and increased strength. It has higher contents of chromium and nitrogen and lower contents of nickel and molybdenum than standard EN 1.4401/4404 and EN 1.4432/1.4436. The composition is designed to match or surpass typical 1.4404 corrosion resistance when PRE value is calculated or pitting corrosion is measured in laboratory. In order to compare the resistance to localized corrosion testing according to ASTM G150, ASTM G48E and a modified version of ASTM G48F were performed. Pitting corrosion of welded 1.4420 was also evaluated with two different filler metals and variations in welding parameters. Stress corrosion cracking susceptibility was assessed with U-bend loading method in three different chloride rich solutions. Uniform corrosion testing was performed according to the MTI-1 procedure in several different solutions and compared to 1.4404 and 1.4432. Overall, the laboratory tests indicate that the corrosion resistance of 1.4420 is somewhat better than 1.4404 and similar to 1.4432 in most environments.
|Title of host publication
|ESSC and DUPLEX 2017 - 9th European Stainless Steel Conference - Science and Market and 5th European Duplex Stainless Steel Conference and Exhibition
|Associazione Italiana di Metallurgiana
|Published - 2017
|MoE publication type
|B3 Non-refereed article in conference proceedings