Evaluation of the retained austenite mechanical stability in the mediumcarbon TRIP steel

• Autorzy: Kokosza A.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The aim of this study was to evaluate the inclination to mechanical destabilization of retained austenite in the microstructure of the TRIP steel containing 0.4% C, 1.5% Mn and 1.2% Si. Design/methodology/approach: The new, simple method for evaluating the mechanical stability of retained austenite was proposed, which is based on the bending test and the measurement of volume fraction of retained austenite by X-ray quantitative phase analysis. The relationship between stress and local strain as well as local volume fraction of this phase in selected locations on the surface of the bending sample were revealed. Findings: The applied heat treatment, modified with respect to the classic one, allowed remain approximately 25 vol.% of the retained austenite in the microstructure of the investigated TRIP steel. It was pointed that retained austenite has high mechanical stability if stress is low. Under influence of the higher stress a partial destabilization this phase occurred. It was found that in the examined steel such mechanical destabilization of retained austenite has two - or three-stage nature. Research limitations/implications: Results of this study indicate a significant stability of retained austenite in the investigated TRIP steel. It is advisable to check how will change the stability of this phase when the stress or strain will be higher than those that occurred in this research. Practical implications: The new method of the evaluation of the retained austenite mechanical stability provides the possibility of an easy and effective estimation of this phase tendency to mechanical destabilisation and to martensite transformation in the steel. In addition, this method allows analysing the influence of the stress as well as the strain on changes in this phase volume fraction, which occur during three-point bending. Originality/value: The proposed method may be used for evaluation of susceptibility of retained austenite on transformation under load. Moreover, developed relationships between volume fraction of retained austenite-stress as well as volume fraction of retained austenite-strain, can be used for interpretation and analyze of mechanical properties changes of heat-treated steels.

Słowa kluczowe

EN

working properties of materials and products; TRIP effect; retained austenite; mechanical stability

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2012
• Tom: Vol. 55, nr 2
• Strony: 323--330
• Opis fizyczny: Bibliogr. 27 poz., rys., tab.

Twórcy

autor

Kokosza A.

• Faculty of Metals Engineering and Industrial Computer Science, AGH-University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland

Bibliografia

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