Optimum Deformation Criteria and Flow Behavior Description of Boron-Alloyed Steel through Numerical Approach

Abstract

The capability of a phenomenological, a physical-based, and a restoration-based model in flow behavior description has been evaluated comparatively to determine the optimum high-temperature deformation condition for a boron-alloyed steel. For this purpose, the hot compression tests are performed over wide ranges of strain rate and temperature. The modified Zerilli-Armstrong model is found to be simple and handy for flow modeling since it employs less material constants compared to the other models. The strain-compensated Arrhenius constitutive equation is accurate and can be used to predict the flow behavior of similar alloys over a wide range of deformation temperatures. The restoration-based constitutive analysis is the most accurate approach for flow modeling because it takes different stages of deformation into account separately. Finally yet importantly, the experimental data are used to develop the efficiency maps and the optimum processing domains are determined.

A Constitutive Equation for the Flow and Densification Behaviors of Powder Metallurgy Fe-0.5C-2Cu Steel at Elevated Temperatures

“…The dynamic flow stresses of the matrix material ( σ 0 ) at different deformation temperatures and strain rates for a constant compressibility of 60% were calculated based on Equation , as shown in Figure . The interrelation between the dynamic flow stress of the matrix material ( σ 0 ), deformation temperature ( T ), and strain rate is similar to the densely wrought material and can be expressed by the Arrhenius equation as: where Q is the activation energy of the hot deformation, J mol −1 . R is the universal gas constant and equals 8.314 J mol −1 K −1 .…”

“…The dynamic flow stresses of the matrix material (s 0 ) at different deformation temperatures and strain rates for a constant compressibility of 60% were calculated based on Equation 2, as shown in Figure 7. The interrelation between the dynamic flow stress of the matrix material (s 0 ), deformation temperature (T), and strain rate _ e ð Þ is similar to the densely wrought material and can be expressed by the Arrhenius equation as: [29][30][31] _ e ¼ AF s 0 ð Þexp À Q RT ð3Þ Figure 5. Interrelation among the dynamic relative density, deformation temperature, and strain rate with the compressibility of 60%.…”

A Modified Arrhenius‐Type Constitutive Model and its Implementation by Means of the Safe Version of Newton–Raphson Method

“…[21] The detailed solution procedure of the Arrhenius-type model could be found in a variety of papers. [9,11,20] They are generally obtained by applying equation logarithmization and liner fitting to some typical data points under the same strains of each stress-strain flow curve. But the hot deformation behavior of materials is the coupling result of TMP parameters such as strain, strain rate, and temperature, and with highly nonlinear.…”

“…It describes the dynamic response of material stress to temperature, deformation rate, strain, and other process parameters under specific conditions. The Arrhenius-type models [5] are widely used in TMP, [6][7][8] owing to their simple form, easy calibration of parameters, and the ability to relatively accurately track the deformation behavior of various materials [9][10][11] throughout the entire thermomechanical process. The Arrhenius equation can be used to determine the activation energy of hot deformation [12] in relation to microstructure evolution as well.…”

Spot Weld Strength Modeling and Processing Maps for Hot-Stamping Steels

“…Common PHS grades contain low to medium contents of carbon (0.06 to 0.3 wt-%) and boron (up to 60 ppm) (Ref. 3) that promotes hardenability of the steel during hot stamping. The process consists of heating the sheet metal to an austenitizing temperature where the material has maximum formability and a direct die-quenching utilizing chilled-forming dies (Ref.…”