Temperature is considered a complicated external factor of the susceptibility of stainless steels to the pitting. This paper deals with the corrosion behaviour of AISI 316Ti stainless steel in temperature range 22 - 80°C in aggressive chloride environments (3 and 5% FeCl3 solutions). The corrosion resistance of tested steel is evaluated on the base of results of exposure immersion tests and cyclic potentiodynamic tests. According to the obtained results the resistance of AISI 316Ti to the pitting is markedly affected by temperature changes in the range 22 – 80°C. Intensity of corrosion attack increases with the rise of Cl− concentration. Gentle changes of temperature and Cl− concentration cause significant differences in character of local damage. The appearance of pitted surfaces changes with the rise of the temperature (a density of pitting increases, a size of pits decreases). The strongest change in appearance is observed between 40 and 50ºC.
AISI 304 austenitic stainless steel is recommended and used for various applications in industry, architecture and medicine. Presence of halides in environment evokes a possibility of the local corrosion which limits seriously exploitation of this material in aggressive conditions. The presented paper is focused on the pitting corrosion resistance (“as received” steel surface) in 1M chloride solution (pH=1.2) at a common (20 °C) and an elevated (50 °C) ambient temperatures. 24-hours exposure immersion test (ASTM G48) and cyclic potentiodynamic test (ASTM G61) are used as the independent test methods. The exposure immersion test is carried out with cross-rolled and longitudinally rolled specimens and the effect of direction of rolling on the resistance to pitting is studied.
Exhaust systems are susceptible to in-service wear because of their exposition to the very aggressive corrosive environment. Various stainless steels grades (mostly ferritic and austenitic, but also martensitic and duplex) and protective coatings are currently used for exhaust system elements to increase their aestetics and corrosion resistance. This article focuses on evaluation and comparison of the common corrosion properties of two stainless steels with different microstructures (ferritic and austenitic) used for exhaust system components at the low ambient temperature (35 °C). An aggressive acidic corrosion solution for electrochemical cyclic potentiodynamic tests (ASTM G61) was chosen to simulate partly inner (condensate) and also external environment (reaction of exhaust gases with water, chlorides in solution after winter road maintenance). Exposure tests of the pitting corrosion resistance were performed according to ASTM G48 standard method.