Hot-working in the γ + α region of TRIP-aided microalloyed steel

• Autorzy: Grajcar A.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The aim of the paper is to investigate the influence of hot-working in the γ + α range and isothermal holding temperature in a bainitic range on a stability of retained austenite in a TRIP-aided microalloyed steel. Design/methodology/approach: The thermomechanical processing in the γ + α range to obtain multiphase structures with the retained austenite in a microalloyed steel was realized. It consisted of plastic deformation of specimens at 750°C or 780°C, oil cooling and isothermal holding in a bainitic region. Degree of deformation was 28 or 50%. To reveal the multiphase structure optical and transmission electron microscopy were used. X-ray diffraction method was employed to determine a volume fraction of retained austenite. Findings: It was found that hot-working in the two-phase region influences essentially a multiphase structure of investigated steel. The ferrite fraction is comparable for heat-treated and thermo-mechanically processed specimens but the ferrite grain size is twice smaller in a case of plastically-deformed specimens. The optimum isothermal holding temperature in a bainitic range is 300°C, independent on austenitizing temperature. The specimens forged in the γ + α range and isothermally held at this temperature made it possible to obtain about 10% of retained austenite. Research limitations/implications: Investigations concerning the influence of isothermal holding time in a bainitic range on the stability of retained austenite should be carried out. Practical implications: The established conditions of the thermomechanical processing can be useful in a development of the hot-rolling technology for TRIP-aided microalloyed steels. Originality/value: The realized thermomechanical processing enabled to obtain about 10% fraction of retained austenite in a steel containing 0.5% Si.

Słowa kluczowe

EN

metallic alloys; TRIP-aided steel; thermomechanical processing; retained austenite

PL

stopy metaliczne; stal typu TRIP; obróbka termodynamiczna; austenit szczątkowy

• Wydawca: International OCSCO World Press
• Czasopismo: Archives of Materials Science and Engineering
• Rocznik: 2007
• Tom: Vol. 28, nr 12
• Strony: 743--750
• Opis fizyczny: Bibliogr. 28 poz., il., tab., wykr.

Twórcy

autor

Grajcar A.

• Division of Constructional and Special Materials, Institute of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland,

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