Influence of the Chemical Composition on the Pitting Corrosion Behavior of Strain Hardened UNS S20910

Abstract UNS S20910 is an austenitic stainless steel used in several industrial applications such as oil and gas, chemical, nuclear and cryogenic industry due to its combination of high strength and excellent corrosion resistance. Strain hardening is typically used to increase the strength of the material without deteriorating other material properties. Despite its remarkable corrosion resistance in most industrial environments, UNS S20910 might undergo pitting corrosion in high chloride containing environments at elevated temperature like those present in drilling operations. In previous examinations, the influence of remelting and strain hardening on the pitting corrosion behavior of UNS S20910 was assessed. In the present study, the influence of the chemical composition on the pitting susceptibility of UNS S20910 in strain hardened condition has been investigated using different techniques. Open-circuit and cyclic potentiodynamic polarization tests were conducted at 88°C in different alkaline chloride-containing solutions ranging from 80 to 140 g/l that emulate typical drilling conditions. Additionally, exposure tests according to ASTM G48 Method A were performed. Experimental results confirm that Molybdenum plays a crucial role in the pitting resistance of UNS S20910 in chloride containing environments at elevated temperatures.