Oxidation Resistance of Medium-Carbon Heat-Resistant Cr-Al Steels in Extreme Conditions

Mykhail M. Yamshinskij, Grigoriy E. Fedorov

Abstract


Background. From the analysis of exploitation of heat-resistant details of thermal power and metallurgical equipment, it was found that the basic characteristic of metallic materials working under extreme conditions is oxidation resistance. However, the choice of materials for work in the conditions of high temperatures and aggressive environments should be made taking into account not only its oxidation resistance but also the possibility of this material to work long time in the conditions of thermal cycling without being damaged, thus thinking about its heat-resistance. Consequently, it is tremendously important to determine the oxidation resistance of iron-based alloys in extreme conditions depending on the presence of main elements – chrome and aluminium – in their content on the basis of study of formation processes on the item surface of high-quality protective oxides films.

Objective. The aim of the paper is to establish the selection rules of heat-resistant iron-based alloys for work in extreme conditions depending on temperatures and aggressive environments and to accumulate some information on their oxidation resistance for the creation of a database and development of methodology how to forecast special properties of alloys.

Methods. Models with 10 mm in diameter and 20 mm in length were tested in a tubular stove at the temperature of 1200 and 1250 °C during 100 hours. Oxidation resistance was determined by a weight method. Phase composition and structure were explored by modern X-ray structural and metallographic methods.

Results. Processes and mechanisms of formation of oxide scale in the conditions of exploitation of items under the temperature 1250 °C in different aggressive environments are established. The optimum boundaries of concentration of basic chemical elements – chrome and aluminium – in heat-resistant alloys for work in extreme conditions depending on temperatures and environments are determined. A database for development of methodology for forecasting of the special properties of Cr-Al steels depending on their chemical composition is created.

Conclusions. Optimal concentration of chrome in heat-resistant Cr steels for work of items at temperatures up to 1100 °C can be considered 25–30 %. To provide high oxidation resistance of items working at temperatures up to 1250 °C in aggressive gas environments, the concentration of Cr in a metal should be within the limits of 25–30 %, and aluminium – from 2.0 to 3.5 %, the relation [% Cr]/[% Al] = 7–10 must be executed. Various gas environments differently effect on oxidation resistance of steels. At the temperatures of 1200 °C items in the water steam environment oxidize faster, and slower in the carbon dioxide environment.

Keywords


Chrome; Aluminium; Cr-Al steel; Structure; Phase composition; Oxidation resistance

References


I.I. Kornilov, Heat-Resistant Alloy no. 3. Moscow, SU: AS USSR Publ., 1947 (in Russian).

V.I. Arharov, Oxidation of Metals at High Temperatures. Moscow, SU: Metallurgizdat, 1945 (in Russian).

Ju.F. Balandin, Thermal Fatigue of Metals. Leningrad, SU: Sudostroenie, 1965 (in Russian).

I.A. Vladimirov, Superalloy Heat-Resistance. Moscow, SU: Oborongiz, 1962 (in Russian).

V.S. Ivanova, Fatigue Failure of Metals. Moscow, SU: Metallurgizdat, 1963 (in Russian).

M.M. Jamshinskij and G.E. Fedorov, “Cr-Al steel scale resistance depending on the content of chromium and aluminum”, Vіsnyk Donbas'koї Derzhavnoї Mashinobudіvnoї Akademії, no. 1 (37), pp. 101–110, 2016 (in Ukrainian).

M. Yamshinskij et al., “The effect of carbon, titanium and rem on oxidation resistance of Cr-Al steels”, IJERT, vol. 5, no. 5, pp. 4–10, 2016.

K.A. Lanskaja, High-Chromium High-Temperature Steels. Moscow, SU: Metallurgizdat, 1976 (in Russian).

M. Jamshins'kij et al., “Special properties of the livestock chromium-aluminum steels”, Metaloznavstvo ta Obrobka Metalіv, no. 3, pp. 14–19, 2004 (in Russian).

M. Jamshins’kij et al., “Chromium-alumina steel oxidation kinetics”, Vіsnyk Donbas'koї Derzhavnoї Mashinobudіvnoї Aka­de­mії, no. 1 (32), pp. 167–172, 2014 (in Ukrainian).

F.F. Himushin, Heat-Resistant Steels and Alloys. Moscow, SU: Metallurgija, 1964 (in Russian).

Je. Gudremon, Special Steels, vol. 1, 2nd ed. Moscow, SU: Metallurgija, 1966 (in Russian).

V.A. Ljutyj, “Cr-Al steel for castings operating at variable temperatures up to 1200 °C”, Ph.D. dissertation, Dept. Techic. Eng., NTUU KPI, Kyiv, 1969 (in Russian).

M. Yamshinskiy et al., “Optimization of chemical composition of heat-resistant chrome-aluminium steels depending on the operation condition of cast parts”, Naukovі Vіstі NTUU KPІ, no. 5, pp. 68–74, 2004 (in Ukrainian).

N.P. Zhuk, Course in the Theory of Corrosion and Protection of Metals. Moscow, SU: Metallurgija, 1976 (in Russian).

Zh. Benar, Oxidation of Metals. Theoretical Basis. Moscow, SU: Metallurgija, 1968 (in Russian).

O. Kubashevskij and B. Gopkins, Oxidation of Metals and Alloys. Moscow, SU: Metallurgija, 1965 (in Russian).

M. Jamshinskij et al., “Increase of special properties of heat-resistant chromium-aluminum steels by micro-alloying and mo­di­fying”, Vіsnyk Donbas'koї Derzhavnoї Mashinobudіvnoї Akademії, no. 1 (15) pp. 220–225, 2009 (in Russian).

M. Yamshinskij and G. Fedorov, “A pooled analysis of heat-resistant Cr-Al steels”, Naukovі Vіstі NTUU KPІ, no. 5, pp. 84–91, 2016 (in Ukrainian).


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DOI: https://doi.org/10.20535/1810-0546.2017.5.97966

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