Abstract
UNS S20910, also known as XM-19 according to ASTM A276, is an austenitic stainless steel used in several industrial applications including oil and gas, chemical, nuclear and cryogenic industry due to its combination of high strength and excellent corrosion resistance. In solution-annealed condition, UNS S20910 shows strength levels significantly higher than conventional austenitic stainless steels. Strength can be further increased by strain hardening without deteriorating other material properties. UNS S20910 exhibits remarkable corrosion resistance in most industrial environments, however, high chloride contents in combination with elevated temperatures may challenge the pitting corrosion resistance of this grade. To enhance pitting corrosion resistance, the microscopic cleanliness can be improved by electro-slag remelting (ESR). In this study, the influence of ESR and strain hardening processes on the pitting susceptibility of UNS S20910 has been investigated. Electrochemical tests were conducted at elevated temperatures in different alkaline chloride-containing solutions ranging from 80 to 140 g/l. Additionally, exposure tests according to ASTM G48 Method A were performed on material in strain-hardened condition. Experimental results confirmed differences in the pitting resistance of UNS S20910 due to the refinement its microstructural cleanliness reached by ESR. It was also confirmed that strain hardening has no detrimental influence on the corrosion behavior of UNS S20910.
