Influence of Cooling Rate on Transformation Behavior of 0.15% V Microalloyed Steel

Saxena, Atul; Kumar, Vinod; Datta, R.

doi:10.1007/s11665-010-9780-4

Cited by 5 publications

(4 citation statements)

References 2 publications

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“…Figure 4 shows the dilatation behavior of an AQ specimen during heating and cooling. With a decreasing cooling rate, volume expansion occurs at a higher temperature during cooling, which is consistent with the previous studies [ 11 , 12 , 13 ]. Therefore, martensite can be transformed at a higher cooling rate, and bainite or ferrite can be transformed as the cooling rate becomes slower in the AQ specimen.…”

Section: Resultssupporting

confidence: 93%

“…As shipbuilding and construction have grown in scale, thick plate steels are increasingly in demand for their high strength and toughness [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. In order for thick plate steels to have high strength and toughness, a thermo-mechanically controlled process (TMCP) is applied during hot rolling, or quenching and tempering (QT) heat treatment is introduced.…”

Section: Introductionmentioning

confidence: 99%

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Estimation of Cooling Rate of High-Strength Thick Plate Steel during Water Quenching Based on a Dilatometric Experiment

Kim

Park

et al. 2023

Materials

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The microstructure and hardness along the thickness direction of a water-quenched, high-strength thick plate with a thickness of 40 mm were investigated with three specimens from the thick plate: surface, 1/4t, and 1/2t (center) thickness, and the phase transformation behavior of the thick plate according to the cooling rate was analyzed through dilatometric experiments. Finally, the cooling rate for each thickness of the thick plate was estimated by comparing the microstructure and hardness of the thick plate along with the thickness with those of the dilatometric specimens. Martensite microstructure was observed on the surface of the water-quenched thick plate due to the fast cooling rate. On the other hand, an inhomogeneous microstructure was transformed inside the thick plate due to the relatively slow cooling rate and central segregation of Mn. A small fraction of bainite was shown at 1/4t thickness. A banded microstructure with martensite and bainite resulting from Mn segregation was developed at 1/2t; that is, the full martensite microstructure was transformed in the Mn-enriched area even at a slow cooling rate due to high hardenability, but a bainite microstructure was formed in the Mn-depleted area owing to relatively low hardenability. A portion of martensite with fine cementite at the surface and 1/4t was identified as auto-tempered martensite with a Bagaryatskii orientation relationship between the ferrite matrix and cementite. The microstructure and hardness as well as dilatation were investigated at various cooling rates through a dilatometric experiment, and a continuous cooling transformation (CCT) diagram was finally presented for the thick plate. Comparing the microstructure and hardness at the surface, 1/4t, and 1/2t of the thick plate with those of dilatometric specimens cooled at various cooling rates, it was estimated that the surface of the thick plate was cooled at more than 20 °C/s, whereas the 1/4t region was cooled at approximately 5~10 °C/s during water quenching. Despite the difficulty in estimation of the cooling rate of 1/2t due to the banded structure, the cooling rate of 1/2t was estimated between 3 and 5 °C/s based on the results of an Mn-depleted zone.

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Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Estimation of Cooling Rate of High-Strength Thick Plate Steel during Water Quenching Based on a Dilatometric Experiment

Kim

Park

et al. 2023

Materials

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“…In turn, at 900C (above A e3 ), only austenite and carbides will be present in the structure. According to [14,15], the total dissolution of vanadium-containing carbides and nitrides in microalloyed steel occurs at a temperature of about 1000C. Therefore, it can be assumed that in the tested cast steel with the addition of vanadium, at 800 and 900C, partial dissolution of vanadium-containing precipitates takes place, which may also reduce the strength properties of the cast steel tested at this temperature.…”

Section: Resultsmentioning

confidence: 99%

Archives of Foundry Engineering

Kalandyk

Zapała

Pałka

2019

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The effect of vanadium microaddition on the strength of low-carbon cast steel containing 0.19% C used, among others, for castings of slag ladles was discussed. The tested cast steel was melted under laboratory conditions in a 30 kg capacity induction furnace. Mechanical tests were carried out at 700, 800 and 900°C using an Instron 5566 machine equipped with a heating oven of  2C stability. Non-standard 8fold samples with a measuring length of 26 mm and a diameter of 3 mm were used for the tests. It has been shown that, compared to cast steel without vanadium microaddition, the introduction of vanadium in an amount of 0.12% to unalloyed, low carbon cast steel had a beneficial effect on the microstructure and properties of this steel not only at ambient temperature but also at elevated temperatures when it promoted an increase in UTS and YS. The highest strength values were obtained in the tested cast steel at 700C with UTS and YS reaching the values of 193 MPa and 187.7 MPa, respectively, against 125 MPa and 82.8 MPa, respectively, obtained without the addition of vanadium. It was also found that with increasing test temperature, the values of UTS and YS were decreasing. The lowest values of UTS and YS obtained at 900°C were 72 MPa and 59.5 MPa, respectively, against 69 MPa and 32.5 MPa, respectively, obtained without the addition of vanadium.

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“…When the non-equilibrium structure of CGHAZ is reheated, because the non-equilibrium structure has a specific orientation, the carbon is directionally diffused to form new austenite with obvious direction and forms a carbon-rich region. During the subsequent cooling process, carbon-rich austenite transforms to M-A constituent [17][18][19][20]. As the heat input increases, the cooling becomes slower, which is beneficial to the precipitation and aggregation of M-A constituent [21][22][23][24].…”

Section: Cghaz Microstructurementioning

confidence: 99%

Effect of heat inputs on microstructure and mechanical properties in CGHAZ of BWELDY960Q steel

Qin¹,

Guo²,

Wang³

et al. 2021

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The Gleeble 1500 test machine was used to simulate the single-pass welding thermal cycle of BWELDY960Q steel under different heat input conditions. In this paper, microstructure observation and mechanical properties of BWELDY960Q steel specimens in coarse grain heat affected zone (CGHAZ) under different heat input conditions were investigated. The results show that under different heat input conditions, the microstructure of CGHAZ is lath martensite, granular bainite, or M-A constituent. As heat input increases, the number and size of the M-A constituent increase accordingly, and the microstructure gradually changes from lath martensite to granular bainite. Meanwhile, compared with the previous samples, the CGHAZ austenite grain diameter increases, and the grain size scale decreases. Furthermore, the value of the CGHAZ impact absorbing energy increases at first but then decreases, while microhardness monotonously decreases. At-20 • C compared with the base metal, the impact absorbing the energy of CGHAZ is significantly reduced, and embrittlement occurs. K e y w o r d s : BWELDY960Q steel, heat inputs, coarse grain heat affected zone, microstructure, mechanical properties

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Influence of Cooling Rate on Transformation Behavior of 0.15% V Microalloyed Steel

Cited by 5 publications

References 2 publications

Estimation of Cooling Rate of High-Strength Thick Plate Steel during Water Quenching Based on a Dilatometric Experiment

Estimation of Cooling Rate of High-Strength Thick Plate Steel during Water Quenching Based on a Dilatometric Experiment

Archives of Foundry Engineering

Effect of heat inputs on microstructure and mechanical properties in CGHAZ of BWELDY960Q steel

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