Materials testing in geothermal fluids have shown that when oxygen is mixed either inadvertently or deliberately with geothermal steam or condensate its corrosivity is increased substantially causing for example pitting corrosion and stress corrosion cracking of stainless steels. A study has been completed using slow strain rate testing to identify the control parameters available to an operator which define the process conditions which lead to stress corrosion cracking for type 304L and 316L stainless steels. Testing involved controlling the corrosion potential of the stainless steel test specimen while completing the slow strain rate test. The objective of the testing was to establish the pH and temperature boundaries which would allow successful use of type 304L or 316L stainless steel in steam condensate. The tests had a parallel objective of demonstrating the extent and morphology of corrosion damage found under controlled conditions to allow a better understanding of results found from empirical studies where corrosion is caused by mixing air into geothermal fluid.Materials testing in geothermal fluids have shown that when oxygen is mixed either inadvertently or deliberately with geothermal steam or condensate its corrosivity is increased substantially causing for example pitting corrosion and stress corrosion cracking of stainless steels. A study has been completed using slow strain rate testing to identify the control parameters available to an operator which define the process conditions which lead to stress corrosion cracking for type 304L and 316L stainless steels. Testing involved controlling the corrosion potential of the stainless steel test specimen while completing the slow strain rate test. The objective of the testing was to establish the pH and temperature boundaries which would allow successful use of type 304L or 316L stainless steel in steam condensate. The tests had a parallel objective of demonstrating the extent and morphology of corrosion damage found under controlled conditions to allow a better understanding of results found from empirical studies where corrosion is caused by mixing air into geothermal fluid.Materials testing in geothermal fluids have shown that when oxygen is mixed either inadvertently or deliberately with geothermal steam or condensate its corrosivity is increased substantially causing for example pitting corrosion and stress corrosion cracking of stainless steels. A study has been completed using slow strain rate testing to identify the control parameters available to an operator which define the process conditions which lead to stress corrosion cracking for type 304L and 316L stainless steels. Testing involved controlling the corrosion potential of the stainless steel test specimen while completing the slow strain rate test. The objective of the testing was to establish the pH and temperature boundaries which would allow successful use of type 304L or 316L stainless steel in steam condensate. The tests had a parallel objective of demonstrating the extent and morphology of corrosion damage found under controlled conditions to allow a better understanding of results found from empirical studies where corrosion is caused by mixing air into geothermal fluid.

Key words: hydrogen sulfide, 304 and 316 stainless steels, stress corrosion cracking, aerated fluids, geothermal