The effect of thermomechanical treatment and tempering on the subsurface microstructure and bendability of direct-quenched low-carbon strip steel

Saastamoinen, Ari; Kaijalainen, Antti; Porter, David; Suikkanen, Pasi

doi:10.1016/j.matchar.2017.10.020

Cited by 22 publications

(13 citation statements)

References 21 publications

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“…This might be due to the fact that the thickness of the samples were much more than the dimensions of the samples used in Ramesh Babu et al [16] where the effects of hot mounting were observed. However, as it was shown in Saastamoinen et al [19], tempering did not affect the final texture therefore tempering due to hot-mounting would not have a final impact with regards to the orientations. The morphological features in the as-quenched steel can be classified as follows:…”

Section: Martensite Morphologymentioning

confidence: 62%

Observations on the Relationship between Crystal Orientation and the Level of Auto-Tempering in an As-Quenched Martensitic Steel

Babu

Nyyssönen

Jaskari

et al. 2019

Metals

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Auto-tempering is a feature of the technologically important as-quenched low-carbon martensitic steels. The focus of this paper is on the morphology of the martensite and the orientation of the last forming untempered regions in relation to the earlier formed auto-tempered martensite in both small and large austenite grains. A low-carbon martensitic steel plate was austenitized for 24 h and quenched to room temperature. The resulting microstructure was characterized using electron microscopy and electron back scattered diffraction (EBSD) imaging. It was found that all the untempered regions in the martensitic microstructure were oriented with the plane normals {100} close to the thickness, or normal, direction of the plates. Variant analysis revealed that the untempered regions and the auto-tempered regions are part of the same packet.

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Section: Martensite Morphologymentioning

confidence: 62%

Observations on the Relationship between Crystal Orientation and the Level of Auto-Tempering in an As-Quenched Martensitic Steel

Babu

Nyyssönen

Jaskari

et al. 2019

Metals

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“…To determine these parameters, Rietveld refinement was used. As in earlier studies, [6], [8], dislocation densities were calculated using the Williamson-Hall method (Equation 1) [9], [10]:…”

Section: Microstructural Evaluationmentioning

confidence: 99%

“…Furthermore, the effect of tempering over a wide range of temperatures has not been fully studied in the case of direct quenched steels. An earlier paper [6] showed that high-temperature tempering increased the bendability of DQ steel. Now this paper reports for the first time the effect of different tempering temperatures on the strength, toughness and bendability of DQ steel.…”

Section: Introductionmentioning

confidence: 98%

The effect of tempering temperature on microstructure, mechanical properties and bendability of direct-quenched low-alloy strip steel

Saastamoinen

Kaijalainen

Heikkala

et al. 2018

Materials Science and Engineering: A

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The tempering of re-austenized, quenched and tempered (RAQT) martensitic steels is an extensively studied and well understood field of metallurgy. However, a similar understanding of the effect of tempering on direct-quenched (DQ) high-strength steels has been lacking. Now, for the first time, the effect of tempering in the range of 250-650 °C on the strength, toughness, bendability, microstructure, crystallography and dislocation density of a DQ steel is reported. In the case of tempering at 570 °C, the effects of having a RAQ or DQ starting condition are compared. For the composition and thermal cycles studied, it was found that a peak tempering temperature in the range of 570-600 °C resulted in a DQT steel with an optimal balance of strength, bendability and toughness, i.e. a yield strength greater than 960 MPa, a minimum usable bending radius of 2 times the sheet thickness and T28J of-50 to-75 °C depending on the test direction. Crystallographic texture, dislocation density and the distribution of carbides are important factors affecting the bendability of DQT strip. Tempering had no effect on texture, but strongly influenced the size and distribution of carbides thereby resulting in differences in bendability and impact toughness transition temperature.

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“…Russo [ 14 , 15 ], TMT is defined as the intermediate thermo-mechanical treatment (ITMT) when the precipitated phase only acts as auxiliary particles, such as the core of the recrystallized nucleation or the obstructor of grain boundary migration (GBM) during the recrystallization process. Many scholars [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ] have made extensive efforts on the process of ITMT. Some scholars [ 16 , 17 ] focused on the traditional combination of cold deformation (CD) and recrystallization annealing treatment, also known as thermal mechanical processing (TMP).…”

Section: Introductionmentioning

confidence: 99%

“…However, the study on the effects of deformation parameters were rarely reported. In addition, most of the studies on ITMT processes are focused on the optimization and improvement of 7000 serials aluminum alloy [ 25 , 26 , 27 , 28 ], Al-Li alloy [ 29 ], and 6000 series aluminum alloys [ 30 , 31 ], Ni-rich Ti-51.5 at.% Ni shape memory alloy [ 32 ], Ti-28Nb-35.4Zr alloy [ 33 ], direct-quenched low-carbon strip steel [ 34 ], commercial austenitic stainless steel [ 35 , 36 , 37 ], and so on. However, the grain refinement effect of the ITMT process for 2219 aluminum alloy is rarely reported.…”

Section: Introductionmentioning

confidence: 99%

Effects of Deformation Parameters on Microstructural Evolution of 2219 Aluminum Alloy during Intermediate Thermo-Mechanical Treatment Process

Liu

Gong

2018

Materials

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To explore the effective way of grain refinement for 2219 aluminum alloy, the approach of ‘thermal compression tests + solid solution treatment experiments’ was applied to simulate the process of intermediate thermo-mechanical treatment. The effects of deformation parameters (i.e., temperature, strain, and strain rate) on microstructural evolution were also studied. The results show that the main softening mechanism of 2219 aluminum alloy during warm deformation process is dynamic recovery, during which the distribution of CuAl2 phase changes and the substructure content increases. Moreover, the storage energy is found to be decreased with the increase in temperature and/or the decrease in strain rate. In addition, complete static recrystallization occurs and substructures almost disappear during the solid solution treatment process. The average grain size obtained decreases with the decrease in deforming temperature, the increase in strain rate, and/or the increase in strain. The grain refinement mechanism is related to the amount of storage energy and the distribution of precipitated particles in the whole process of intermediate thermal-mechanical treatment. The previously existing dispersed fine precipitates are all redissolved into the matrix, however, the remaining precipitates exist mainly by the form of polymerization.

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The effect of thermomechanical treatment and tempering on the subsurface microstructure and bendability of direct-quenched low-carbon strip steel

Cited by 22 publications

References 21 publications

Observations on the Relationship between Crystal Orientation and the Level of Auto-Tempering in an As-Quenched Martensitic Steel

Observations on the Relationship between Crystal Orientation and the Level of Auto-Tempering in an As-Quenched Martensitic Steel

The effect of tempering temperature on microstructure, mechanical properties and bendability of direct-quenched low-alloy strip steel

Effects of Deformation Parameters on Microstructural Evolution of 2219 Aluminum Alloy during Intermediate Thermo-Mechanical Treatment Process

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