Mechanical properties and structure of the Cr-Mo-V low-alloyed steel after long-term service in creep condition

• Autorzy: Dobrzański J. , Zieliński A. , Krztoń H.
• Języki publikacji: EN

Abstrakty

EN

Purpose: of this paper is to present the changes of the mechanical properties and structure in material components of the power station boiler after long-term creep service made of Cr-Mo-V low-alloyed steel. Design/methodology/approach: The investigated material has been obtained from the Polish power stations. All examined elements have exceeded their assessed life of 100 000 hours. Mechanical properties and structure examinations were carried out on materials after long-term service in creep conditions. The microstructure have been observed using a light and a scanning electron microscope. The investigation of the development of the precipitation processes were done by X-ray diffraction phase analysis. Findings: Carbide precipitations evolution in correlation to the life exhaustion extent were presented. Residual life in creep short tests was done. Residual life in correlation to changes structure and developed of carbide precipitation processes were presented. Practical implications: The presented methods can be used for materials evaluation operating in creep conditions. Originality/value: The presented results changes in the mechanical properties, structure and in the precipitation processes are applied to evaluation of the condition of the elements in further industrial service.

Słowa kluczowe

EN

mechanical properties; structure; phase analysis; creep service; degradation; residual life

PL

właściwości mechaniczne; struktura; analiza fazowa; długotrwałe próby pełzania stali; degradacja; trwałość resztkowa

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2007
• Tom: Vol. 23, nr 1
• Strony: 39--42
• Opis fizyczny: Bibliogr. 16 poz., rys., tab.

Twórcy

autor

Dobrzański J.

autor

Zieliński A.

autor

Krztoń H.

• Institute for Ferrous Metallurgy, ul. K. Miarki 12/14, 44-100 Gliwice, Poland,

Bibliografia

• [1] J. Dobrzański, Analysis of structure and properties changes of the lCr-0.5Mo type steel subjected to long-term creep as the basis for forecasting the life of the power industry equipment components PhD Thesis, Katowice (unpublished), 1995 (in Polish).
• [2] A. Hernas, J. Dobrzański, Life-time and Damage of Boilers and Steam Turbines Elements, Publishing House of the Silesian University of Technology, Gliwice, 2003 (in Polish).
• [3] J. Dobrzański, A. Zieliński, State evaluation of critical elements material after long-term service in creep condition, Advances in Material Science, in print.
• [4] J. Dobrzański, Material diagnostics in evaluation of the state and extended service time forecast in addition to the computational life of pipelines in creep service, Power Engineering 12 (2002) 937- 943 (in Polish).
• [5] J. Dobrzański, Internal damage processes in low alloy chromium-molybdenum steels during high-temperature creep service, Journal of Materials Processing Technology 157-158 (2004) 297-303.
• [6] J. Dobrzański, The classification method and the technical condition evaluation of the critical elements' material of power boilers in creep service made from the 12Cr-lMo-V, Journal of Materials Processing Technology 164-165 (2005) 785-794.
• [7] J. Dobrzański, A. Zieliński, M. Sroka, Microstructure, properties investigations and methodology of the state evaluation of T23 (2,25Cr-0,3Mo-l,6W-V-Nb) steel in boilers application, International Journal of Materials and Product Technology (2007) - in print.
• [8] J. Dobrzański, A. Zieliński, Forecasting of service life and residual life of the material and welded joint of the elements of the pressure part of Power boilers after long term creep service, COST 538 Annual report - unpublished, 2007.
• [9] D. Renowicz, A. Hernas, M. Cieśla, K. Mutwil, Degradation of the cast steel parts working in power plant pipelines. Journal of Achievements in Materials and Manufacturing Engineering. 18 (2006) 219-222.
• [10] L.A. Dobrzański, M. Sroka, J. Dobrzański, Application o: neural networks to classification of internal damages in steels working in creep service, Journal of Achievements in Materials and Manufacturing Engineering 20 (2007) 303-306.
• [11] J. Dobrzański, M. Sroka, A. Zieliński, Methodology of classification of internal damage the steels during creep service, Journal of Achievements in Materials and Manufacturing Engineering 18 (2006) 263-266.
• [12] M.E. Staubli, Final summary report of turbine groupe COST 522 - steam power plant (2003) Baden.
• [13] ASTM A213/A213M-99A - Standard Specification for Seamless Ferritic and Austenitic Alloy - Steel Boiler, Superheater, and Heat-Exchanger Tubes.
• [14] N. Komai, T. Imazato, Effect of tempering times on creep strength in ASME Gr.23 (2.25Cr-1.6W steel), Proceedings of the International Scientific Conference "Materials for Advanced Power Engineering" . Liege. 2006. 997-1009.
• [15] D. Renowicz. M. Ciesla. Crack initiation in steel parts working in boilers and steam pipelines, Journal of Achievements in Materials and Manufacturing Engineering 21 (2007) 49-52.
• [16] S. Król, M. Pietrzyk. Formation of corrosion products protecting surfaces of the boiler proper tubes from the combustion chamber. Journal of Achievements in Materials and Manufacturing Engineering 21 (2007) 45-48.