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Abstract

Nodular cast irons are used in a wide range of industrial applications, especially in the automotive industry. SiMo-type of nodular cast iron is suitable for high-temperature applications, for example the exhaust manifolds of the combustion engines; SiCu-type of nodular cast iron is used in various components of tribotechnical units. These automotive components often work in a corrosive environment. Therefore, the aim of this paper is to compare the corrosion resistance of two types of the nodular cast irons (SiMo-type and SiCu-type). Corrosion resistance was determined by the exposure immersion test at ambient temperature. Specimens of both types of nodular cast iron were immersed in 3.5 % NaCl solution (to simulate sea water) and gradually removed from the solution after 1, 2, 4 and 8 weeks. Subsequently, the weight loss (g) and the average corrosion rate (g m−2 day−1) were calculated. Experimental results show that nodular cast iron alloyed by Si and Mo has higher corrosion resistance than the nodular cast iron alloyed with Si and Cu. Moreover, the mechanical properties (evaluated by tensile test, impact bending test and hardness test) and fatigue properties of both types of nodular cast iron has been compared in the paper.

Abstract

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.

Abstract

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.

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