Dilatometric characterization of pearlite dissolution in 0.1c-0.5mn low carbon low manganese steel

The authors acknowledge financial support from the European Coal and Steel Community (ECSC- 7210. EC/939) and the Spanish Comisio´n Interministerial de Ciencia y Tecnologı´a (CICYT-MAT95-1192-CE)Peer reviewe

Kinetics Model of Isothermal Pearlite Formation in a 0.4C-1.6Mn Steel

The present article is concerned with a theoretical and experimental study of the growth kinetics of pearlite in a 0.4C-1.6Mn medium carbon steels. Factors controlling the isothermal formation of this microconstituent are explored in this work. In this sense, the transition temperature between local equilibrium (LE) and no partition local equilibrium (NPLE) growth mechanisms is theoretically determined. Moreover, the nucleation of pearlite has been considered as a cementite precipitation process on a moving austenite-ferrite interface. Finally, a theoretical model is presented in this work to calculate the evolution of austenite-to-pearlite transformation with time at a very wide temperature range.The authors acknowledge financial support from Spanish Ministerio de Ciencia y Tecnologı´a (MAT2001-1617). C. Capdevila would like to express his gratitude to the Consejo Superior de Investigaciones Cientifı´cas for financial support as a Post-Doctoral contract (I3P PC-2001-1). F.G. Caballero would like to thank the Consejerı´a de Educacio´n. D.G. de Investigacio´n de la Comunidad Auto´noma de Madrid (CAM) for the financial support in the form of a Postdoctoral Research GrantPeer reviewe

Kinetics Model of Isothermal Pearlite Formation in a 0.4C-1.6Mn Steel

The present article is concerned with a theoretical and experimental study of the growth kinetics of pearlite in a 0.4C-1.6Mn medium carbon steels. Factors controlling the isothermal formation of this microconstituent are explored in this work. In this sense, the transition temperature between local equilibrium (LE) and no partition local equilibrium (NPLE) growth mechanisms is theoretically determined. Moreover, the nucleation of pearlite has been considered as a cementite precipitation process on a moving austenite-ferrite interface. Finally, a theoretical model is presented in this work to calculate the evolution of austenite-to-pearlite transformation with time at a very wide temperature range.The authors acknowledge financial support from Spanish Ministerio de Ciencia y Tecnologı´a (MAT2001-1617). C. Capdevila would like to express his gratitude to the Consejo Superior de Investigaciones Cientifı´cas for financial support as a Post-Doctoral contract (I3P PC-2001-1). F.G. Caballero would like to thank the Consejerı´a de Educacio´n. D.G. de Investigacio´n de la Comunidad Auto´noma de Madrid (CAM) for the financial support in the form of a Postdoctoral Research GrantPeer reviewe

Incubation time of isothermally transformed allotriomorphic ferrite in medium carbon steels

The authors acknowledge financial support from the Spanish Comisio´n Interministerial de Ciencia y Tecnologı´a (CICYT) (project-PETRI 95-0089-OP). GSB Acero S.A. and CEIT are thanked for providing the steel and their collaboration in this projectPeer reviewe

Modeling of the interlamellar spacing of isothermally formed pearlite in a eutectoid steel

The authors acknowledge financial support from the European Coal and Steel Community (ECSC-7210. EC/939) and the Spanish Comisio´n Interministerial de Ciencia y Tecnologı´a (CICYT-MAT95-1192-CE)Peer reviewe

Reciprocating-sliding wear behaviour of nanostructured and ultra-fine high-silicon bainitic steels

The reciprocating sliding wear behaviour of high-silicon bainitic steels has been studied on microstructures obtained from two alloys containing 0.3 and 1.0 wt.% C, which were isothermally transformed between 200 and 425 ºC. Results show an order of magnitude improvement in the wear resistance of the nano-scaled bainitic structures with respect to the ultra-fine with similar hardness values. The scale of the microstructure and the level of retained austenite determine the wear mechanism and eventually, the wear ratesupport of Ministerio de Economia y Competitividad (MINECO) and Fondo Europeo de Desarrollo Regional (FEDER) for funding this research under the Contract IPT-2012-0320-420000, as well the financial backing from the the Research Fund for Coal and Steel in the form of RFSR‐CT‐2014‐00016.Peer reviewe

Design of Novel High-Strength Bainitic Steels

With careful design, mixed microstructures consisting of fine plates of upper bainitic ferrite separated by thin films of stable retained austenite have exhibited impressive combinations of strength and toughness in high-silicon bainitic steels. The silicon suppresses the precipitation of brittle cementite leading to an improvement in toughness. The essential principles governing the optimisation of such microstructures are well established, particularly that large regions of unstable high-carbon retained austenite must be avoided. The aim of the present work was to see how far these concepts can be extended to achieve the highest ever combination of strength and toughness in bulk-samples, consistent with certain hardenability and processing requirements.Peer reviewe

Estimation of dislocation density in bainitic microstructures using high-resolution dilatometry

It is possible by means of high resolution dilatometry together with a model based on isotropic dilatation and atomic volumes, to estimate the dislocation density introduced in the microstructure as a consequence of the isothermal decomposition of austenite into bainitic ferrite. The relatively high dislocation density associated with this microstructure is attributed to the fact that the shape deformation accompanying this displacive transformation is accommodated by plastic relaxationThe authors gratefully acknowledge the financial support of the Spanish MCYT. Plan Nacional deI+D (Programa I3 2007–2009) Ref. 200760I013 and the RFCS Programme for 2007 (Commission of the European Communities) Ref. RFSR-CT-2008-00022Peer reviewe

Influence of V Precipitates on Acicular Ferrite Transformation. Part 1: The Role of Nitrogen

6 pages, 8 figures, 1 table.-- This is Part I of paper "Influence of V Precipitates on Acicular Ferrite Transformation", Part II available at: http://hdl.handle.net/10261/17758Vanadium Award 2009-Council of the Institute of Materials, Minerals and Mining-UK for the most outstanding paper in the metallurgy and technology of vanadium and its alloys. Sponsored and selected by the Vanadium International Technical Committee (Vanitec).This paper (part 1 of a two part study) deals with the influence of N in its combination with V, as V(C, N) precipitates, on the decomposition of austenite into acicular ferrite. Likewise, the intragranular nucleation potency of V(C, N) precipitates is analyzed through the continuous cooling transformation diagrams (CCT) of two C–Mn–V steels with different contents of N under two different austenitising temperatures, i.e. different austenite grain sizes. The results clearly show that for austenite to decompose into acicular ferrite is necessary, first to have a representative fraction of V(C, N) precipitates within austenite, and second to decorate the austenite grain boundaries with proeutectoid ferrite so bainite can not form. Part 2 of the study concerns with the influence that those precipitates have on the kinetics of acicular ferrite formation during austenite isothermal decomposition.The authors would like to acknowledge the Commission of the European Communities for the financial support in the frame of the RFCS Programme for 2004 (RFS-PR-03136). Also to the Spanish MCYT through the project MAT2005-24485-E.Peer reviewe

Acceleration of Low-temperature Bainite

Recent work has shown that bainitic ferrite plates produced by transformation at low temperatures can be as thin as 20 nm with a hardness in excess of 650 HV. However, it may take several days in order to achieve the required degree of transformation at low temperatures. In this work we report methods for accelerating the rate of reaction without compromising strength.Engineering and Physical Sciences Research Council and Dirección General de Investigacion de la Comunidad Autonoma de Madrid (CAM)Peer reviewe