Experiment and simulation of static softening behavior of alloyed steel during round bar hot rolling

Wang, X.; Chandrashekhara, K.; Buchely, Mario F.; Lekakh, Semen Naumovich; Aken, David C. Van; O’Malley, Ronald J.; Ridenour, Gary; Scheid, E.

doi:10.1016/j.jmapro.2020.02.031

Cited by 16 publications

(9 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the previous studies of SRX behavior, generally, n is around 1. For instance, n of medium carbon alloyed steel (0.38C–1.3Mn–0.57Si) is 0.782, [ 34 ] and that of low‐density ferritic steel (0.035C–0.051Mn–4.26Al–1.1Ni–0.19Si) is 0.93. [ 19 ] Therefore, n of the studied 0.15C–7Mn steel is smaller compared with other metallic materials, which is ascribed to the strong SRV and inhomogeneous nucleation.…”

Section: Resultsmentioning

confidence: 99%

“…Some methods were proposed to determine the fraction of static softening and volume fraction of SRX in the two‐hit compression, including offset method, strain recovery method, back extrapolation method, and average stress method. [ 34,43 ] The offset method was adopted to evaluate restoration effect caused by SRX and SRV, in which the static softening fraction X S is written as

X_{normalS} = \frac{σ_{m} - σ_{2}}{σ_{m} - σ_{1}}

where σ m is the value of instantaneous stress at unloading point; σ 1 and σ 2 are the offset yield stress (0.2%) values corresponding to the first and second deformation, respectively. The softening behavior during interval holding is affected by the deformation parameters, such as deformation temperature, strain rate, and interval time.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Microstructure Evolution and Kinetics of Static Recrystallization of Medium Mn Steel in the Two‐Hit Isothermal Compression

Sun

Zhang

Wang

et al. 2020

steel research int.

View full text Add to dashboard Cite

The thermal deformation behavior and microstructure evolution of medium Mn steel (0.15C–7Mn) are investigated by the two‐hit compression tests. The results reveal that different static softening dynamics are the functions of deformation temperature, interval time, and strain rate. The short static softening plateaus are exhibited in the static softening curves during post‐deformation holding at 950 °C and 0.1, 1 s−1. Based on the electron backscatter diffraction (EBSD) analysis, the progresses of static recovery (SRV) and static recrystallization (SRX) are enhanced by the increment of deformation temperature. The frequencies of medium angle boundaries (MAGBs) and high angle boundaries (HAGBs) increase gradually with an increased interval time at 1000 °C and 0.1 s−1, which suggests that both SRV and SRX contribute to static softening, but the predominant softening mechanism is SRV. In addition, the influence of temperature, interval time, and strain rate on the distribution and average magnitude of grain size is investigated. The deformation temperature and strain rate have a significant influence not only on average grain dimension, but also on the distribution of grain size. Interval time has great influence on average grain size, but has slight effect on distribution of grain size.

show abstract

Section: Resultsmentioning

confidence: 99%

X_{normalS} = \frac{σ_{m} - σ_{2}}{σ_{m} - σ_{1}}

Section: Methodsmentioning

confidence: 99%

Microstructure Evolution and Kinetics of Static Recrystallization of Medium Mn Steel in the Two‐Hit Isothermal Compression

Sun

Zhang

Wang

et al. 2020

steel research int.

View full text Add to dashboard Cite

show abstract

“…Static softening occurs during hot rolling of steel and several methods are used to determine the softening fraction for a given strain, deformation temperature, and interpass time (time between two deformation strains). [ 10–12 ] Double hit test is a widely used approach to measure softening fraction using laboratory‐based thermomechanical simulators. [ 13 ] In this test, the fraction of static softening is defined by the degree of softening after an initial deformation by carrying out a second deformation after a specified time interval.…”

Section: Introductionmentioning

confidence: 99%

Effect of Sample Geometry on Strain Uniformity and Double Hit Compression Tests for Softening Kinetics Determination

Tamanna

Slater

Davis

2022

steel research int.

View full text Add to dashboard Cite

Static softening is an essential process during the hot rolling of steel to refine grain size and improve mechanical properties. The double hit test is used to measure the static softening volume fraction from the flow stress curves. Herein, the influence of different sample geometries on the determination of softening fraction from the double hit test for conditions where 0–99% softening is expected. The double hit tests are modeled in DEFORM for conventional sample geometries in both uniaxial compression and standard plane strain compression tests, and an additional simulation of a modified plane strain compression test sample geometry, designed to provide more uniform strain distributions, is also performed. A user routine is incorporated into the model to predict the localized softening volume fraction from localized strain based on known softening equations and set back the localized strain value to zero while the softening volume fraction reaches 85%. The standard plane strain compression test geometry shows a strong strain gradient resulting in inaccurate softening fraction volume predictions from flow stress, whereas the uniaxial compression test and modified plane strain compression test geometries show better predictions of softening volume fraction from the flow stress data.

show abstract

“…Presently, the research on static softening behavior is mainly based on double-pass thermal compression experiments [ 13 , 14 , 15 ], which have been widely conducted in various metals and alloys, such as Al-Zn-Mg-Cu alloys with various Zr additions [ 16 ], alloyed steel [ 17 ], titanium added ultra-low carbon (ULC-Ti) steel [ 18 ], 7150 aluminum alloy [ 19 ], Al–6Mg alloy [ 20 ], and vanadium micro-alloyed high manganese austenitic steels [ 21 ]. The reports on static softening mainly focus on the softening mechanism and kinetics modeling.…”

Section: Introductionmentioning

confidence: 99%

Static Softening Behavior and Modified Kinetics of Al 2219 Alloy Based on a Double-Pass Hot Compression Test

Liu

Gong

et al. 2020

Materials

View full text Add to dashboard Cite

In this paper, the static softening mechanism of a 2219 aluminum alloy was studied based on a double-pass isothermal compression test. For the experiment, different temperatures (623 K, 723 K, and 773 K), strain rates (0.1/s, 1/s, and 10/s), deformation ratios (20%, 30%, and 40%), and insulation periods (5 s, 30 s, and 60 s) were used. Based on the double-pass flow stress curves obtained from the experiment, the step rate expressed by the equivalent dynamic recrystallization fraction is dependent on the deformation parameters, which increases with the increase in strain rate and insulation time, while it decreases with the increase in temperature and strain. Based on the microstructure observed using electron backscattered diffraction (EBSD), the static softening mechanism of the Al 2219 alloy is mainly static recovery and incomplete static recrystallization. A new expression for the static recrystallization fraction is proposed using the reduction rate of the sub-grain boundary. The dependent rule on the deformation parameters is consistent with the step rate, but it is of physical significance. In addition, the modified static recrystallization kinetics established by the new SRX fraction method was proven to have a good modeling and prediction performance under given deformation conditions.

show abstract

Experiment and simulation of static softening behavior of alloyed steel during round bar hot rolling

Cited by 16 publications

References 18 publications

Microstructure Evolution and Kinetics of Static Recrystallization of Medium Mn Steel in the Two‐Hit Isothermal Compression

Microstructure Evolution and Kinetics of Static Recrystallization of Medium Mn Steel in the Two‐Hit Isothermal Compression

Effect of Sample Geometry on Strain Uniformity and Double Hit Compression Tests for Softening Kinetics Determination

Static Softening Behavior and Modified Kinetics of Al 2219 Alloy Based on a Double-Pass Hot Compression Test

Contact Info

Product

Resources

About