Precipitation of carbides in Cr - Mo - V cast steel after service and regenerative heat treatment

• Autorzy: Golański G. , Wieczorek P.
• Języki publikacji: EN

Abstrakty

EN

The paper presents results of research on precipitation processes in chromium - molybdenum - vanadium cast steel. The examined material was the following cast steel grade: L21HMF and G17CrMoV5 - 10 (L17HMF) after long-term operation at elevated temperatures and after regenerative heat treatment. Identification of precipitates was performed by means of the transmission electron microscope using carbon extraction replicas and thin foils. On the basis of identifications it has been proved that in the structure of investigated cast steel grades, degraded by long-term operation, there are a few sorts of carbides with diverse stability, such as: M3C; M2C, M23C6, MC, M7C3. Moreover, the occurrence of compound complexes of precipitates - the so called 'H-carbides' - has been revealed. Heat treatment of the examined cast steels contributed to changes in morphology and precipitation type. Whilst in the bainitic structure, obtained through heat treatment, only the occurrence of carbide types, such as: M3C; M23C6 and MC has been noticed.

Słowa kluczowe

EN

metallographic; heat treatment; cast steel; carbides

PL

metalografia; obróbka cieplna; staliwo; węglik

• Wydawca: Komisja Odlewnictwa Polskiej Akademii Nauk Oddział w Katowicach
• Czasopismo: Archives of Foundry Engineering
• Rocznik: 2009
• Tom: Vol. 9, iss. 1
• Strony: 97--102
• Opis fizyczny: Bibliogr. 9 poz., rys., tab., wykr.

Twórcy

autor

Golański G.

autor

Wieczorek P.

• Institute of Materials Engineering, Częstochowa University of Technology, Armii Krajowej 19, Częstochowa, Poland,

Bibliografia

• [1] G. Golański, Influence of tempering temperature on mechanical properties of cast steels, Arch. Foundry Eng., 8, 4, (2008), 47 - 50.
• [2] G. Golański, S. Stachura, J. Kupczyk, B. Kucharska-Gajda, Heat treatment of cast steel using normalization and intercritical annealing, Arch. Foundry Eng., 7, 1, (2007), 123- 126.
• [3] J. Janovec., M. Svoboda, A. Výrostková, TA. Kroupa, Time-temperature-precipitation diagrams of carbide evolution in low alloy steels, Mater. Sc. Eng., A, 402, 1- 2, (2005), 288 - 293.
• [4] G. D. Pigrova, T. A. Tchyzhik, Phase composition of 1.5Cr - Mo - V rotor steel as factor of cooling rate from austenitic region, Materials at High Temperatures, 13, 3, (1995), 121 - 123.
• [5] P. Sevc, J. Janovec., M. Koutnik, A. Výrostková, Equilibrium grain boundary segregation of phosphorus in 2.6Cr-0.7Mo-0.3V steels, Acta Metall. Mater., 43, 1, 1995, 251 - 258.
• [6] B. A. Senior, A critical review of precipitation behavior in 1Cr - Mo - V rotor steels, Mater. Sc. Eng. A, 103, (1988), 263.
• [7] M. C. Murphy, G. D. Branch, The microstructure, creep and creep - rupture properties of Cr - Mo - V steam turbine castings, JISI, (1969), 1347 - 1364.
• [8] K. R. Williams, B. Wilshire, Microstructural instability of 0.5Cr - 0.5Mo-0.25V creep - resistant steel during service at elevated temperatures, Mater. Sci. Eng., 47, (1981), 151.
• [9] S. Stachura, Zmiany struktury i własności mechanicznych w stalach i staliwach eksploatowanych w podwyższonych temperaturach, Energetyka, 2, (1999), 109 - 115.