Continuously Cooled Ultrafine Bainitic Steel with Excellent Strength–Elongation Combination

Das, Sourav; Haldar, Arunansu

doi:10.1007/s11661-013-2173-1

Cited by 33 publications

(31 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to reduce the fraction of M/A islands and to refine the bainitic microstructures, several variants of the conventional IBT process, e.g. the two-step or multi-step IBT process [105][106][107], the continuous cooling process [90,93,[99][100][101]106,[108][109][110][111], the "disturbed" bainitic austempering (DBAT) [112] or the bainite-based quenching and partitioning (BQ&P) [113] process, have been proposed and explored. The two-step IBT process involves bainite formation first at a higher temperature and then at a lower temperature [105,106].…”

Section: Starting Microstructures and Processing Routesmentioning

confidence: 99%

Fundamentals and application of solid-state phase transformations for advanced high strength steels containing metastable retained austenite

Dai

Chen

Ding

et al. 2021

Materials Science and Engineering: R: Reports

129

View full text Add to dashboard Cite

Over many decades, significant efforts have been made to improve the strength-elongation product of advanced high strength steels (AHSSs) by creating tailored multi-phase microstructures. Successive solid-state phase transformations for steels with a well selected chemical composition turned out to be the key instrument in the realisation of such microstructures. In this contribution, we first provide a brief review of the desired microstructures for Transformation-induced plasticity (TRIP), Carbide-free Bainitic (CFB), Quenching & Partitioning (Q&P) and Medium Manganese steels followed by comprehensive discussions on the phase transformations to be used in their creation. The implications for the steel composition to be selected are addressed too. As the presence of the right amount and type of metastable retained austenite (RA) is of crucial importance for the mechanical performance of these AHSSs, special attention is paid to the important role of successive solid-state phase transformations in creating the desired fraction and composition of RA by suitable element partitioning (in particular C and Mn). This critical partitioning not only takes place during final cooling (austenite decomposition) but also during the back transformation (austenite reversion) during reheating.This review aims to be more than just descriptive of the various findings, but to present them from a coherent thermodynamic / thermo-kinetic perspective, such that it provides the academic and industrial community with a rather complete conceptual and theoretical framework to accelerate the further development of this important class of steels. The detailed stepwise treatment makes the review relevant not only for experts but also metallurgists entering the field.

show abstract

Section: Starting Microstructures and Processing Routesmentioning

confidence: 99%

Fundamentals and application of solid-state phase transformations for advanced high strength steels containing metastable retained austenite

Dai

Chen

Ding

et al. 2021

Materials Science and Engineering: R: Reports

129

View full text Add to dashboard Cite

show abstract

“…This ensures that a high amount of austenite remains untransformed and is retained at room temperature. Further details of alloy design can be found elsewhere [12]. …”

Section: Alloy Designmentioning

confidence: 99%

Mechanical Properties of a Bainitic Steel Producible by Hot Rolling

Rana

Chen

Haldar

et al. 2017

Archives of Metallurgy and Materials

View full text Add to dashboard Cite

A carbide-free bainitic microstructure is suitable for achieving a combination of ultra high strength and high ductility. In this work, a steel containing nominally 0.34C-2Mn-1.5Si-1Cr (wt.%) was produced via industrial hot rolling and laboratory heat treatments. The austenitization (900°C, 30 min.) and austempering (300-400°C, 3 h) treatments were done in salt bath furnaces. The austempering treatments were designed to approximately simulate the coiling step, following hot rolling and run-out-table cooling, when the bainitic transformation would take place and certain amount of austenite would be stabilized due to suppression of carbide precipitation. The microstructures and various mechanical properties (tensile properties, bendability, flangeability, and room and subzero temperature impact toughness) relevant for applications were characterized. It was found that the mechanical properties were highly dependent on the stability of the retained austenite, presence of martensite in the microstructure and the size of the microstructural constituents. The highest amount of retained austenite (~ 27 wt.%) was obtained in the sample austempered at 375°C but due to lower austenite stability and coarser overall microstructure, the sample exhibited lower tensile ductility, bendability, flangeability and impact toughness. The sample austempered at 400°C also showed poor properties due to the presence of initial martensite and coarse microstructure. The best combination of mechanical properties was achieved for the samples austempered at 325-350°C with a lower amount of retained austenite but with the highest mechanical stability.

show abstract

“…The thermal conductivity and specific heat of the workpiece material were taken as 44.5 W/mK and 0.475 J/g °C, respectively, for the finite element analysis (FEA) calculations. Ultrafine bainitic steel has a 1370 MPa ultimate tensile strength and its chemical composition is given in Table 6 [14,53].…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

An advanced modelling to improve the prediction of thermal distribution in friction stir welding (FSW) for difficult to weld materials

Sarikavak

2020

J Braz. Soc. Mech. Sci. Eng.

View full text Add to dashboard Cite

This study explores the thermal distribution of high-strength engineering alloys during the friction stir welding process (FSW). Materials which are difficult to weld or are unweldable by conventional welding processes can be successfully welded by FSW. The specific analysis and modification of the process require an understanding of the actual mechanism of the process. Therefore, a transient, three-dimensional, thermo-mechanical finite element model (FEM) for FSW was developed. The model calculates the temperature distribution during the welding process considering various boundary conditions such as rotational speed, linear speed, normal pressure, tool diameter and material properties. The thermo-mechanical FEM calculations consider the effects of conduction and convection heat transfer. The numerical results are successfully compared and validated by experimental results published in the literature for aluminium alloy, titanium alloy and steel (mild and bainitic) as workpiece materials. The model was found to be useful for understanding the effects of changes in different system parameters, and for selecting the optimum welding conditions before undertaking high-cost physical testing.

show abstract

Continuously Cooled Ultrafine Bainitic Steel with Excellent Strength–Elongation Combination

Cited by 33 publications

References 18 publications

Fundamentals and application of solid-state phase transformations for advanced high strength steels containing metastable retained austenite

Fundamentals and application of solid-state phase transformations for advanced high strength steels containing metastable retained austenite

Mechanical Properties of a Bainitic Steel Producible by Hot Rolling

An advanced modelling to improve the prediction of thermal distribution in friction stir welding (FSW) for difficult to weld materials

Contact Info

Product

Resources

About