Bainitic stabilization of austenite in low alloy steels

M. L. Brandt*, Gregory B Olson

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The stabilization of retained austenite via bainitic transformation was studied in a 'triple-phase' ferrite/bainite/austenite steel of composition 0.26C-1.52Si-1.2Mn. The volume fraction and stability of retained austenite are varied by the isothermal transformation time at 752F (400C) following intercritical annealing at 1418F (770C). Austenite stability is measured using the Bolling-Richman technique for determination of the Msσ temperature. Austenite content is measured by X-Ray diffraction, and austenite carbon content is estimated from lattice parameter measurements. Strength and ductility measured in both uniaxial and plane-strain tension are correlated with the amount and stability of austenite. While austenite content peaks at 3 minutes transformation time, stability continues to increase out to 5 minutes in association with a saturation of austenite carbon content and a continued refinement of austenite particle size. Despite the reduced austenite content of 8 percent, the higher stability provided by the 5 minute treatment gives superior mechanical properties, achieving a plane-strain uniform ductility of 25 percent with a 3 percent flow strength of 83 ksi (570 MPa). The austenite stability appears to be less than the theoretical optimum, and further ductility enhancement should be achievable with increased stability.

Original languageEnglish (US)
Title of host publicationGilbert R Speich Symp Proc Fundam Aging Tempering Bainitic Martensitic Steel Prod
Editors Anon
PublisherPubl by Iron & Steel Soc of AIME
Pages257-265
Number of pages9
ISBN (Print)0932897770
StatePublished - Dec 1 1992
EventGilbert R. Speich Symposium Proceedings on Fundamentals of Aging and Tempering in Bainitic and Martensitic Steel Products - Montreal, Que, Can
Duration: Oct 25 1992Oct 28 1992

Other

OtherGilbert R. Speich Symposium Proceedings on Fundamentals of Aging and Tempering in Bainitic and Martensitic Steel Products
CityMontreal, Que, Can
Period10/25/9210/28/92

ASJC Scopus subject areas

  • Engineering(all)

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