A Finite Element Method for the Prediction of Thermal, Metallurgical, and Mechanical Behavior of Rebars in the TempCore Process

Dimatteo, A.; Vannucci, Marco; Colla, Valentina

doi:10.1002/srin.201500029

Cited by 13 publications

(6 citation statements)

References 16 publications

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“…The first step is to calculate the film coefficient (h) between the rebar and water during quenching. The film coefficient depends mainly on temperature among other variables such as: rebar diameter, tube diameter, water flow rate, and water pressure [20][21][22]. For simplicity, the coefficient could be taken as an average fixed value, for each rebar diameter, throughout the model.…”

Section: Methodsmentioning

confidence: 99%

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Microstructure and Mechanical Properties of V-Alloyed Rebars Subjected to Tempcore Process

Ahmed

Ibrahim

Galal³

et al. 2021

Metals

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Two B400B-R and B500B grade rebars were industrially produced through a Tempcore process. The standard chemical composition of B500B grade was additionally alloyed with 0.067 wt.% V to enhance its mechanical properties. A set of optimized processing parameters were applied to manufacture two different diameters D20 (Ø 20 mm) and D32 (Ø 32 mm). The microstructure -mechanical properties relationships were evaluated using optical and scanning electron microscopes, hardness, and tensile testing. In addition, a thermal model was developed to define the thermal cycle evolution during cooling in the quenching & tempering box (QTB) to simulate the kinetics of V(C,N) precipitation. The microstructure observations showed a typical graded microstructure consisting of ferrite-pearlite core and outer tempered martensite ring for both grades of both diameters. The optimized processing parameters for B400B-R of D32 (compared with D20) resulted in softening of the core (from 160 to 135 HV10) and tempered martensite surface (from 220 to 200 HV10) as well as in decreasing the yield strength (from 455 to 413 MPa) and tensile strength (from 580 to 559 MPa). On the contrary, an increase in hardness of the core (from 165 to 175 HV10) and the outer tempered martensite (from 240 to 270 HV10), in addition to an increase in yield strength (from 510 to 537 MPa) at almost the same level of tensile strength of 624–626 MPa are observed for B500B grade D32 compared with D20. The modeling and simulation calculations suggest that the manufacturing D32 rebars of B500B grade involves longer quenching time in the QTB which allow deeper tempered martensite surface along with a relatively higher core temperature that renders faster kinetics and larger volume fraction of V(C,N) precipitates. The current study demonstrates that the full potential of V-alloying can be exploited when a sufficient quenching time at the equalization temperature is achieved, which is valid for D32 rebars.

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Section: Methodsmentioning

confidence: 99%

“…The analysis is based on adjusting the film coefficient to obtain temperatures that are equal or nearly equal to that measured at the inlet and outlet of the Tempcore box. Dimatteo et al [22], established an equation that predicts h from the rebar geometry and of the cooling water flow, Equation ( 2…”

Section: Methodsmentioning

confidence: 99%

Microstructure and Mechanical Properties of V-Alloyed Rebars Subjected to Tempcore Process

Ahmed

Ibrahim

Galal³

et al. 2021

Metals

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“…Recent modeling approaches [29][30][31][32][33][34][35][36] to examine the TempCore TM process thus far are restricted to the analysis of the heat conduction problem and the microstructural evolution as well as to unribbed rebars. The mechanical properties at room temperature are predicted based on the phase fractions of the constituting phases and the phase properties.…”

Section: Introductionmentioning

confidence: 99%

An Approach to Predict Geometrically and Thermo-Mechanically Induced Stress Concentrations in Ribbed Reinforcing Bars

Robl

Wölfle

Hameed

et al. 2022

Metals

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Ribbed reinforcing steel bars (rebars) are used for the reinforcement of concrete structures. In service, they are subjected to cyclic loading. Several studies addressing the relationship between rib geometry, stresses at the rebar surface induced by service loads and the rebar fatigue performance can be found in literature. However, the rebar’s fatigue performance is also influenced by residual stresses originating from the manufacturing process. In this contribution, a modeling approach is proposed to examine geometrically and thermo-mechanically induced stress concentrations in ribbed reinforcing bars made of the steel grade B500B. A linear-elastic load stress analysis and a thermo-mechanical analysis of the manufacturing process are conducted. The results are discussed and compared to literature results. In case of the load stress analysis, the results agree well with findings reported in literature and extend the current state of knowledge for B500B rebars with small diameters. In case of the thermo-mechanical analysis, compressive residual stresses at the rebar surface between two ribs and tensile residual stresses in the longitudinal direction at the tip of the ribs can be reported.

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“…The temperature of the water and the applied time defines the steel microstructure and thereafter the final mechanical properties. The common microstructure obtained is a ferrite core followed by a mix ferrite-martensitic (or bainitic transition crown which is the responsible of the smooth changes in the stresses between microstructures, see Figure 3a [18]) and finally, an outer martensitic layer. The aim of the presented experimental study was the characterization of the mechanical properties of 12 mm diameter steel bars used for the calibration and validation of the given model.…”

Section: Materials Behaviour Tempcore ® Steel Reinforcement Barsmentioning

confidence: 99%

“…Specifically annular distribution of the mechanical properties is defined for this steel manufacture system [6,[12][13][14][15][16][17][18], in which the outer layers resist more than the inner core. Consequently, due to the non-uniform cross-section reduction of steel corrosion, the non-uniform stress throughout the cross-section and the reduction of the bar capacity are emphasised.…”

Section: Introductionmentioning

confidence: 99%

Mechanical model to evaluate steel reinforcement corrosion effects on σ – ε and fatigue curves. Experimental calibration and validation

Fernandez

Bairán

Bernat

2016

Engineering Structures

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• Mechanical model to evaluate the mechanical properties of corroded steel • Calibration and validation of a mechanical model to evaluate corrosion effect on tensile and fatigue curves • An experimental study on material properties characterization for not corroded bars produced with TEMPCORE ® system. • Experimental data validates the presented model from 0% up to 60% degree of corrosion.

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A Finite Element Method for the Prediction of Thermal, Metallurgical, and Mechanical Behavior of Rebars in the TempCore Process

Cited by 13 publications

References 16 publications

Microstructure and Mechanical Properties of V-Alloyed Rebars Subjected to Tempcore Process

Microstructure and Mechanical Properties of V-Alloyed Rebars Subjected to Tempcore Process

An Approach to Predict Geometrically and Thermo-Mechanically Induced Stress Concentrations in Ribbed Reinforcing Bars

Mechanical model to evaluate steel reinforcement corrosion effects on σ – ε and fatigue curves. Experimental calibration and validation

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