Effect of cooling time t8/5 on microstructure and toughness of Nb–Ti–Mo microalloyed C–Mn steel

Wang, Xiaonan; Chen, Xia-ming; Wen, Feng; Guo, Pengfei; Yang, Lei; Yan, Qingzhi; Di, Hongshuang

doi:10.1007/s42243-018-0146-8

Cited by 5 publications

(2 citation statements)

References 17 publications

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“…[25] CaO-MnO-Al 2 O 3 -SiO 2 inclusions also transformed into Al 2 O 3 at the electrode tip after adding aluminum powders into the slag. [26] Both of the removal and the modification of inclusions during ESR process occurred at the slag-metal interface. The slag-metal interface could be divided into three stages, including the liquid film-slag interface, the droplet-slag interface, and the metal pool-slag interface.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Nonmetallic Inclusions during the Electroslag Remelting Process

Wen

Ren

Zhang

et al. 2021

steel research int.

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The evolution of inclusions during the electroslag remelting (ESR) process, especially the inclusions in droplets is investigated by an industrial trial which remelts a plain carbon steel billet in the slag of CaF2–Al2O3–CaO–MgO. Results show that oxide inclusions change from SiO2–MnO to Al2O3–MnO during the ESR process. The transfer of aluminum from the slag to the steel increases the aluminum content in the steel and causes the reaction between (MnO), (SiO2) in inclusions with the [Al] in the steel to generate (Al2O3) inclusions. Thermodynamic results show that inclusion evolution is mainly influenced by the temperature and the total Al content in the steel. With the increase in temperature at the electrode tip, the MnO content in inclusions increases rapidly. Meanwhile, as the aluminum transfers from the slag to the steel, the Al2O3 inclusion increases clearly with the corresponding decrease in MnO and SiO2 inclusions. In addition, from the electrode to the ingot, the number density of inclusions decreases from 208.82 to 33.49 # mm−2, whereas the average size increases from 3.79 to 5.76 μm. Both the chemical modification and the physical absorption of slag mainly occur at the liquid film and droplet stage.

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Section: Introductionmentioning

confidence: 99%

Evolution of Nonmetallic Inclusions during the Electroslag Remelting Process

Wen

Ren

Zhang

et al. 2021

steel research int.

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“…However, a sufficient fraction of AF in the microstructure is needed to enable its positive effects regarding toughness [23]. Additionally, aside from AF's other factors in the microstructure, such as inclusions [24][25][26][27], PAGS [21,[28][29][30][31][32], residual austenite and/or martensite-austenite compounds [3,9,28,[33][34][35][36], might have the opposite effect on the toughness of HAZ.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Impact Toughness in Simulated Coarse-Grained Heat-Affected Zone of Al-Deoxidized and Ti-Deoxidized Offshore Steels

Tervo

Kaijalainen

Javaheri

et al. 2021

Metals

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The presence of acicular ferrite (AF) in the heat-affected zone (HAZ) of steels used offshore is generally seen as beneficial for toughness. In this study, the effects of varying fractions of AF (0–49 vol.%) were assessed in the simulated, unaltered and coarse-grained heat-affected zones (CGHAZ) of three experimental steels. Two steels were deoxidized using Ti and one using Al. The characterization was carried out by using electron microscopy, energy-dispersive X-ray spectrometry, electron backscatter diffraction and X-ray diffraction. The fraction of AF varied with the heat input and cooling time applied in the Gleeble thermomechanical simulator. AF was present in one of the Ti-deoxidized steels with all the applied cooling times, and its fraction increased with increasing cooling time. However, in other materials, only a small fraction (13–22%) of AF was present and only when the longest cooling time was applied. The impact toughness of the simulated specimens was evaluated using instrumented Charpy V-notch testing. Contrary to the assumption, the highest impact toughness was obtained in the conventional Al-deoxidized steel with little or no AF in the microstructure, while the variants with the highest fraction of AF had the lowest impact toughness. It was concluded that the coarser microstructural and inclusion features of the steels with AF and also the fraction of AF may not have been great enough to improve the CGHAZ toughness of the steels investigated.

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