Evolution of microstructure during the "quenching and partitioning (Q&amp;P)" treatment

Kumar, Sachin; Singh, Shiv Brat

doi:10.1016/j.mtla.2021.101135

Cited by 16 publications

(20 citation statements)

References 68 publications

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“…Similar deviations between predicted and experimentally measured results have also been reported in literature [8,15,34,48] which are attributed mainly to the violation of the ideal partitioning conditions such as complete carbon partitioning, suppression of the bainite formation and carbide precipitation during partitioning [34,63]. In addition, segregation of some carbon atoms might take place at dislocations in martensite and at lath boundaries [18,45] and these carbon atoms no longer remain available to enrich the untransformed austenite during partitioning. The application of the KM equation [56] which is commonly used to predict the kinetics of martensite transformation in this model, also needs to be reanalysed since it is applicable to a specific range of chemical composition.…”

Section: Optimum Quenching Temperature (Qt Opt )supporting

confidence: 85%

“…The carbon content of decarburised martensite away from the carbon-enriched regions was measured to be 0.063 ± 0.005 wt-% using 3D APT analysis of a Fe-0.24C-1.87Mn-1.31Si-0.34Al-0.32Mo-0.66Ni (wt-%) steel quenched to 260°C and partitioned at 400°C for 300 s [45], which is quite high than the corresponding CCE value (Table 1). HajyAkbary et al [33] have estimated the carbon concentration of primary martensite to be 0.05 wt-% after partitioning at 400°C for 200 s using 3D APT analysis.…”

Section: Incomplete Carbon Partitioning From Primary Martensitementioning

confidence: 99%

“…Even Al and P produce similar retardation effects on cementite formation but to a lower extent [37][38][39]. The lower QTs and higher PTs were found beneficial to minimise the extent of bainite transformation during the partitioning treatment [33,40]. In addition to these competing reactions, the formation of carbides within martensite during initial quenching [33,35,41], loss of carbon in the segregation of carbon atoms at dislocations and defects in martensite and at interfaces [2,17,18,33,[42][43][44], incomplete carbon partitioning from primary martensite during partitioning [45] are also possible which have not been considered in the published literature on the Q&P process.…”

Section: Introductionmentioning

confidence: 99%

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Quenching and partitioning (Q&P) process: A critical review of the competing reactions

Kumar

2022

Materials Science and Technology

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The quenching and partitioning (Q&P) process has been proposed recently as an alternative route to obtain a unique microstructure consisting of decarburised martensite and retained austenite that results in a superior balance between strength and ductility. The stabilisation of austenite after the Q&P processing is mainly achieved through its carbon enrichment as a result of carbon partitioning from primary martensite formed during initial quenching. However, carbon partitioning is usually accompanied by complex competing reactions which are known to affect the austenite retention at room temperature. This review is a critical assessment of these competing reactions during the Q&P process and their implication on the evolution of microstructure.

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Section: Optimum Quenching Temperature (Qt Opt )supporting

confidence: 85%

Section: Incomplete Carbon Partitioning From Primary Martensitementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quenching and partitioning (Q&P) process: A critical review of the competing reactions

Kumar

2022

Materials Science and Technology

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“…This is in agreement with investigations reported for different Q&P steels in other studies. [ 34–36 ] Moreover, it is apparent that larger fractions of RA could be stabilized by increasing C contents in the bulk, while the peak was shifted to lower T Q . This corresponds to the observations in other studies [ 34,37 ] and can be explained by two main factors.…”

Section: Resultsmentioning

confidence: 99%

Tailoring the Ductility Characteristics of Lean‐Medium Mn Quenching and Partitioning Steels with Varying C Contents

Kaar

Križan

Schneider

et al. 2023

steel research int.

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During recent years, quenching and partitioning (Q&P) steels have gained strong interest due to their promising lightweight potential and crashworthiness. With their microstructure consisting of tempered martensite (α″) and C‐enriched retained austenite (RA), they are characterized by balanced ductility, combining the formability properties of conventional dual‐phase and complex‐phase steels at elevated strength levels. This study thoroughly examines three chemical compositions with 4.0 wt% Mn, 1.5 wt% Si, and varying C contents between 0.10 and 0.20 wt% with regard to their structure–properties relationship. In this context, various parameters are derived from tensile testing to assess the formability behavior of the investigated steels. The results clearly demonstrate a strong effect of the RA fraction and its mechanical stability on the ductility characteristics of lean‐medium Mn Q&P steels. Generally, the optimum exploitation of the transformation‐induced plasticity effect favors high global ductility, but the resulting heterogeneities in the microstructure remarkably impair the local one. By increasing the C content, larger RA fractions can be stabilized, shifting the ductility characteristics from rather local toward global. For this reason, medium C content of 0.15 wt% allows for the adjustment of the optimum microstructure leading to desired balanced ductility.

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“…It is expected to exert the transformation-induced plasticity (TRIP) effect during plastic deformation. [5] The strain-induced M transformation increases both strength and ductility.AHSS researchers have worked on Q-P steel in a variety of ways, including developing a theoretical model and exploring RA stability, [5][6][7][8] as well as optimizing experimental processes like the annealing, quenching, and partitioning stages. [9][10][11][12][13] Previous studies have indicated that the partial austenitization Q-P process may provide superior overall mechanical properties for the experimental steel than the full austenitization Q-P process, and that the quenching temperature (QT) has a greater impact on the composition of the room temperature microstructure.…”

mentioning

confidence: 99%

Effect of Quenching Temperature on the Strengthening Mechanism of Low‐Carbon Microalloyed Quenching and Partitioning Steel

Chu

Chen

Liu

et al. 2022

steel research int.

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Herein, the microstructures of the low‐carbon microalloyed quenching and partitioning (Q–P) steels are multiphase with ferrite (F), martensite (M), and retained austenite (RA) at different quenching temperatures (QTs), i.e., 140, 180, 240, and 300 °C. The volume fraction of fresh martensite (FM) increases from 8.6% to 61.4%, but the tempered martensite (TM) decreases from 49.7% to 0% with the QT increase. Meanwhile, the size of the precipitates (Nb, Ti)C tends to increase, whereas the fraction of the precipitates decreases first and then increases. With the increase of the QT, the yield strength (YS) decreases, the tensile strength (TS) increases, and the elongation first increases and then decreases. Additionally, the strengthening mechanism of Q–P steel is quantitatively analyzed in terms of F, M, RA, and precipitation strengthening. This study shows that F makes the same contribution to YS for the tested steels. The major strengthening mechanism of the Q–P steel is contributed by M, which accounts for about 43.7% to 56.0% of total YS. RA greatly influences the plasticity of Q–P steel and provides little to YS. With an increase in QT, the precipitation strengthening values first decrease and then increase.

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Evolution of microstructure during the "quenching and partitioning (Q&P)" treatment

Cited by 16 publications

References 68 publications

Quenching and partitioning (Q&P) process: A critical review of the competing reactions

Quenching and partitioning (Q&P) process: A critical review of the competing reactions

Tailoring the Ductility Characteristics of Lean‐Medium Mn Quenching and Partitioning Steels with Varying C Contents

Effect of Quenching Temperature on the Strengthening Mechanism of Low‐Carbon Microalloyed Quenching and Partitioning Steel

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