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Corrosion properties of 1.4512 ferritic and 1.4404 austenitic steels for the automotive industry

Zatkalíková Viera, Markovičová Lenka, Wróbel-Knysak Anna

System Safety : Human - Technical Facility - Environment

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2019

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Vol. 1, nr 1

745--752

EN

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.

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Influence of temperature on corrosion resistance of austenitic stainless steel in cl¯ containing solutions

Zatkalíková Viera, Markovičová Lenka

Production Engineering Archives

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2019

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Vol. 25

43--46

EN

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.

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Effect of chemical composition and plastic deformation on corrosion properties of highMn austenitic steels in alkaline solution

Kozłowska A., Grajcar A

Archives of Materials Science and Engineering

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2016

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Vol. 77, nr 1

31--39

EN

Purpose: The aim of the paper is to compare the corrosion properties of two high-Mn austenitic steels with various Al and Si additions in 0.1M NaOH solution using a potentiodynamic method. Design/methodology/approach: The steels used for the investigation were thermomechanically rolled in 3 passes. The final thickness of about 2 mm was obtained at a temperature of 850°C. Three groups of samples were prepared: thermomechanically rolled, thermomechanically rolled and additionally annealed at 900°C for 20 min, thermomechanically rolled and additionally cold deformed in static tensile test to total elongation of 36%. Corrosion resistance of investigated steels was examined using the potentiodynamic method. The metallographic inspection of corrosion damage included scanning electron microscope observations. The chemical analyses of the corrosion pits were carried out using EDS techniques. Findings: It was found that X4MnSiAlNbTi27-4-2 and X6MnSiAlNbTi26-3-3 steels were characterized by relatively high corrosion resistance in 0.1M NaOH solution independently of their state. EDS analysis revealed that corrosion pits nucleated preferentially at nonmetallic inclusions such as MnS and AlN. Results of potentiodynamic tests showed that cold deformation had the highest influence on decreasing the corrosion resistance of investigated steels. Thermomechanically treated and supersaturated specimens showed lower values of corrosion current density and consequently less amount of corrosion damage. Research limitations/implications: To investigate in more detail the corrosion behaviour of high-manganese austenitic steels, the impedance spectroscopy investigations will be carried out. Practical implications: The knowledge of the corrosion resistance of high-Mn steels has a significant effect on their industrial application in the automotive industry. Originality/value: The corrosion resistance of two high-manganese austenitic steels with different initial microstructures was compared in alkaline solution.

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Influence of cold rolling on the corrosion resistance of austenitic steel

Kurc A., Kciuk M., Basiaga M.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 38, nr 2

154-162

EN

Purpose: The paper analyzes the effects of plastic deformation in cold working process on the corrosion resistance, micro-hardness and mechanical properties of austenitic stainless steel X5CrNi18-10. Design/methodology/approach: Corrosion resistance of X5CrNi18-10 steel was examined using weight and potentiodynamic methods. In the weight method, the specimens were immersed in the prepared solution for 87 days. The evaluation of the corrosion behaviour of investigated steel in the potentiodynamic method was realized by registering of anodic polarization curves. The VoltaLabŽ PGP 201 system for electrochemical tests was applied. The tests were carried out at room temperature in electrolyte simulating artificial sea water (3.5% NaCl). Registering of anodic polarization curves was conducted at the potential rate equal to 1 mV/s. As the reference electrode the saturated calomel electrode (SCE) was applied, the auxiliary electrode was platinum electrode. Mechanical properties were evaluated on the basis of the static tensile and Vickers micro-hardness test. The observations of the surface morphology after corrosive tests were carried out using Scanning Electron Microscope SUPRA™25. Findings: According to the results of potentiodynamic analyses it was found that plastic deformation in a cold working of austenitic steel grade X5CrNi18-10 affected to lower its corrosion resistance in 3.5% NaCl solution, what has an essential meaning in industrial applications of this group of materials. Research limitations/implications: The microscope observations of the surface samples subjected to corrosion resistance test in 3.5% NaCl solution permitted to evaluate types and the rate of corrosion damages. Practical implications: The obtained results can be used for searching the appropriate way of improving the corrosion resistance of a special group of steels. Originality/value: The corrosion behaviour in chloride solution of a Cr-Ni austenitic stainless steel was investigated.

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Corrosion behaviour of Fe-Mn-Si-Al austenitic steel in chloride solution

Opiela M., Grajcar A., Krukiewicz W.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 33, nr 2

159-165

EN

Purpose: The aim of the paper is to investigate the corrosion behaviour of the new-developed high-manganese austenitic steel in 0.5n NaCl solution. Design/methodology/approach: The steel used for the investigation was thermomechanically rolled and solution heat-treated from a temperature of 850°C. Corrosion resistance of investigated steel was examined using weight and potentiodynamic methods. In the weight method, the specimens were immersed in the prepared solution for 24h. In the potentiodynamic method, anodic polarization curves with a rate of potential changes of 1 mV/s in the anodic direction were registered. After the current density being equal 1 mA/cm2 was achieved, the direction of polarization has been changed. Basing on the registered curves, the pitting potential, repassivation potential, polarization resistance and corrosion current were determined. Findings: It was found that the steel is characterized by a partially recrystallized austenitic microstructure with numerous annealing twins and slip bands. According to the results of potentiodynamic analyses it was found that the samples of examined steel show poor corrosion resistance in the NaCl solution. The observed corrosion pits are related to the chemical composition. It is connected with the high dissolution rate of Mn and Fe atoms in NaCl solution. Fractographic analyses of samples revealed corrosion products on their surface in a form of pits with diversified size. Research limitations/implications: To investigate in more detail the corrosion behaviour of high-manganese steel, the investigations should include steels with a wider Al concentration. Practical implications: The obtained results can be used for searching the appropriate way of improving the corrosion resistance of a modern group of high-manganese austenitic steels. Originality/value: The corrosion behaviour in chloride solution of a new-developed Fe-Mn-Si-Al steel was investigated.