Grain Size Evolution and Mechanical Properties of Nb, V–Nb, and Ti–Nb Boron Type S1100QL Steels

Foder, Jan; Burja, Jaka; Klančnik, Grega

doi:10.3390/met11030492

Cited by 7 publications

(5 citation statements)

References 42 publications

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“…The last rolling passes were performed at low temperatures of 700-720 • C under TMCP, inhibiting the dynamic and metadynamic recrystallization [44]. Additionally, this temperature range refers to the precipitation of fine V/Nb carbides [45], contributing to recrystallization suppression [46]. Subsequently, the structure acquired a heavily deformed pattern with a high dislocation density.…”

Section: Microstructure Characterizationmentioning

confidence: 99%

Enhancing the Tensile Properties and Ductile-Brittle Transition Behavior of the EN S355 Grade Rolled Steel via Cost-Saving Processing Routes

Zurnadzhy,

Stavrovskaia,

Chabak

et al. 2024

Materials

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Structural rolled steels are the primary products of modern ferrous metallurgy. Consequently, enhancing the mechanical properties of rolled steel using energy-saving processing routes without furnace heating for additional heat treatment is advisable. This study compared the effect on the mechanical properties of structural steel for different processing routes, like conventional hot rolling, normalizing rolling, thermo-mechanically controlled processing (TMCP), and TMCP with accelerating cooling (AC) to 550 °C or 460 °C. The material studied was a 20 mm-thick sheet of S355N grade (EN 10025) made of low-carbon (V+Nb+Al)-micro-alloyed steel. The research methodology included standard mechanical testing and microstructure characterization using optical microscopy, scanning and transmission electronic microscopies, energy dispersive X-ray spectrometry, and X-ray diffraction. It was found that using different processing routes could increase the mechanical properties of the steel sheets from S355N to S550QL1 grade without additional heat treatment costs. TMCP followed by AC to 550 °C ensured the best combination of strength and cold-temperature resistance due to formation of a quasi-polygonal/acicular ferrite structure with minor fractions of dispersed pearlite and martensite/austenite islands. The contribution of different structural factors to the yield tensile strength and ductile–brittle transition temperature of steel was analyzed using theoretical calculations. The calculated results complied well with the experimental data. The effectiveness of the cost-saving processing routes which may bring definite economic benefits is concluded.

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Section: Microstructure Characterizationmentioning

confidence: 99%

Enhancing the Tensile Properties and Ductile-Brittle Transition Behavior of the EN S355 Grade Rolled Steel via Cost-Saving Processing Routes

Zurnadzhy,

Stavrovskaia,

Chabak

et al. 2024

Materials

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show abstract

“…The addition of V/Nb is beneficial to refine the grain. It is easy for V to form carbides in steel, and the carbides can pin the grain boundaries to inhibit grain growth and refine grains [5]. Nb not only has the same effect as V for grain refinement but can also form compounds with other elements in the steel.…”

Section: Microstructure Analysismentioning

confidence: 99%

“…The most common microalloying elements in steels are Nb, Ti, and V. They can be used alone or in combination with each other [4]. Foder et al [5] measured the grain size and mechanical properties of the boron-type S1100QL steel, and the mechanical properties of adding V and Nb together were found to be better than those of adding Nb separately. The heat treatment process has a notable effect on the comprehensive performance of bearing steel.…”

Section: Introductionmentioning

confidence: 99%

Effect of Austempering on Mechanical Properties of Nb/V Microalloyed Bainitic Bearing Steel

et al. 2022

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In this study, a multi-element microalloyed GCr15Si1MoNbV bainitic bearing steel was designed by adding trace amounts of Nb and V. The bainite/martensite/retained austenite/undissolved carbide multiphase bearing steel with a short heat-treated cycle and remarkable comprehensive mechanical properties was prepared via low-temperature austempering, which was compared with a traditional quenched and tempered martensitic microstructure. The results showed that the comprehensive mechanical properties of the low-temperature bainitic microstructure of the Nb/V microalloyed bearing steel were better than those of a traditional tempered martensitic microstructure. In addition, as the isothermal temperature increased, the impact toughness of experimental steel was significantly improved, and the hardness decreased slightly. The tensile strength was improved with the increase in isothermal time. As the isothermal temperature increased, the bainite content of the experimental steel rose, and the stability of the retained austenite enhanced due to more carbon atoms being partitioned into it. The research work in this paper made a preliminary exploration for the application of Nb/V microalloyed bainitic bearing steel in the bearing field and provided some basic data for reference.

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“…[5,6] The Nb element is generally completely dissolved in austenite during the heating process before hot-forging, and the solid-solution Nb delays grain boundary migration and recrystallization through the solute drag effect. [7,8] Nb (C, N) precipitates in the austenite and at the sub grain boundary to prevent the growth of the original austenite grains. [9] Nb can also increase the strength of the steel by refining the pearlite lamellar spacing.…”

Section: Introductionmentioning

confidence: 99%

Effect of V–Nb Composite Microalloying on Microstructure and Properties of Non‐Quenched and Tempered Forged Steel

Sun

Song

Zhao

et al. 2023

steel research int.

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Herein, non‐quenched and tempered forging steels containing V and V–Nb are designed, and the mechanical properties and microstructure of two steels are compared and analyzed. The comprehensive mechanical properties of V–Nb containing steel are as follows: the yield strength is 525.1 MPa, the impact energy AkV is 62.1 J at ambient temperature, and the elongation is 26.1%. It is shown in the results that the addition of Nb element can refine the grain size (17.2 μm), increase the ferrite content (54.1%), and refine the lamellar spacing of pearlite (274 nm). The formation of V (C, N) particles on MnS inclusions can promote fine ferrite nucleation and growth, and Nb element can further promote ferrite nucleation by forming coarser (V, Nb) (C, N) particles. The difference of yield strength and hardness between the two steels is mainly caused by the difference of precipitation strengthening, the precipitation‐strengthening increment of V–Nb containing steel is 18.31 MPa higher than that of V containing steel, which is because the coarser‐size (V, Nb) (C, N) particles produce stronger precipitation‐strengthening effect. But the large‐sized MnS inclusions are beneficial to the increase of crack driving force and reduce the plasticity and toughness.

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Grain Size Evolution and Mechanical Properties of Nb, V–Nb, and Ti–Nb Boron Type S1100QL Steels

Cited by 7 publications

References 42 publications

Enhancing the Tensile Properties and Ductile-Brittle Transition Behavior of the EN S355 Grade Rolled Steel via Cost-Saving Processing Routes

Enhancing the Tensile Properties and Ductile-Brittle Transition Behavior of the EN S355 Grade Rolled Steel via Cost-Saving Processing Routes

Effect of Austempering on Mechanical Properties of Nb/V Microalloyed Bainitic Bearing Steel

Effect of V–Nb Composite Microalloying on Microstructure and Properties of Non‐Quenched and Tempered Forged Steel

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