A novel design: Partitioning achieved by quenching and tempering (Q–T &amp; P) in an aluminium-added low-density steel

Yi, Hong; Chen, P.; Hou, Ziyong; Hong, Ni; Cai, H. L.; Xu, Yun Bo; Wu, Di; Wang, G.D.

doi:10.1016/j.scriptamat.2012.10.018

Cited by 78 publications

(27 citation statements)

References 24 publications

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“…Several variants of the original Q&P process, e.g. stepping-quenching and partitioning (S-Q&P) [182], quenching-partitioning-tempering (Q&P-T) [165,183], quenching-tempering and partitioning (Q-T&P) [184,185] and Quenching and flash-partitioning (QFP) [186], have been proposed and explored more recently. During the S-Q-P process, the steels are repeatedly quenched to a final temperature between M s and M f while the carbon is partitioned at a higher temperature [182].…”

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

128

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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.

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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

128

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“…The process is conducted to provide sufficient time at either the initial quenching temperature or above, and to thus stabilize the retained austenite to an ambient temperature. At present, the Q&P process has gradually evolved to quenching-partitioning-tempering (Q-P-T) [3], direct quenching and partitioning (DQ&P) [4,5], and quenching and tempering-associated partitioning (Q-T&P) [6]. The Q-P-T treatment emphasized the application of precipitation strengthening to the Q&P process.…”

Section: Introductionmentioning

confidence: 99%

The Mechanism of High-Strength Quenching-Partitioning-Tempering Martensitic Steel at Elevated Temperatures

et al. 2019

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High-strength medium-carbon martensitic steel was heat treated through a quenching-partitioning-tempering (Q-P-T) treatment. Both the mechanism for improved ductility and the high temperature stability of austenite were investigated. The Q-P-T martensitic steel showed good products of strength and elongation (PSE) at various deformation temperatures ranging within 25–350 °C. The optimum PSE value (>57,738 MPa%) was achieved at 200 °C. The microstructure of the Q-P-T steel is constituted of laths martensite with dislocations, retained austenite located within lath martensite and small niobium carbides (NbC), and/or transitional ε-carbides that precipitated in the lath martensite. The good ductility can be mainly attributed to the laminar-like austenite that remained within the lath-martensite. The austenite can effectively enhance ductility through the effect of dislocation absorption by the retained austenite and through transformation-induced plasticity. The relationship between the microstructures and mechanical properties was investigated at high deformation temperatures.

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“…Recently, δ-TRIP steel, due to its low density, a product of ultimate tensile strength (UTS) and total elongation (TE) (up to 23 GPa·%) similar to the third generation of advanced high-strength steels (AHSS), and excellent welding properties, is expected to become the materials of automobile safety parts and structural parts [1,2]. Yi et al [3] found an alloy (its precise composition is Fe-0.4C-0.5Mn-0.2Si-0.5Cr-3.5Al wt %), having a density of 7.455 × 10 3 kg/m 3 , is approximately 5% lighter than that without the aluminum addition, which has a density of 7.8145 × 10 3 kg/m 3 . Abedi et al [4] found a duplex low-density steel with an exact chemical composition of Fe-17.5Mn-8.3Al-0.74C-0.14Si (wt %), having a density of 6.8 × 10 3 kg/m 3 .…”

Section: Introductionmentioning

confidence: 99%

High-Temperature Mechanical Properties of 4.5%Al δ-TRIP Steel

2019

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The high-temperature mechanical properties of a 4.5% Al-containing δ-transformation-induced plasticity (TRIP) steel were studied by using the Gleeble 3500 thermomechanical simulator. The zero ductility temperature (ZDT) and the zero strength temperature (ZST) were measured, and the brittle zones were divided. The phase transformation zone was determined by differential scanning calorimetry (DSC). The temperature of the phase transformation and the proportion of the phase were calculated by the Thermo-Calc software. The ZDT and the ZST of the 4.5% Al-containing δ-TRIP steel are 1355 and 1405 °C, respectively. The first brittle zone and the third brittle zone of the steel are 1300–1350 °C and 800–975 °C, respectively. The reason for the embrittlement of the third brittle zone of the 4.5% Al-containing δ-TRIP steel is that the α-ferrite formed at the austenite grain boundary causes the sample to crack along the grain boundary under stress. The ductility of the 4.5% Al-containing δ-TRIP steel decreases first and then increases with the increase of the α-ferrite. When the proportion of the α-ferrite reaches 37%, the reduction of area (RA) of the 4.5% Al-containing δ-TRIP steel is reduced to 44%. The 4.5% Al-containing δ-TRIP steel has good resistance to the high-temperature cracking.

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A novel design: Partitioning achieved by quenching and tempering (Q–T & P) in an aluminium-added low-density steel

Cited by 78 publications

References 24 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

The Mechanism of High-Strength Quenching-Partitioning-Tempering Martensitic Steel at Elevated Temperatures

High-Temperature Mechanical Properties of 4.5%Al δ-TRIP Steel

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