Modeling of Mechanical Characteristics in Hot Deformation of 4130 Steel

Abstract

In this investigation, hot compression tests were performed at 900 °C − 1100 °C and strain rate of 0.001 − 0.1 s−1 to study hot deformation behavior and flow stress model of 4130 steel. Based on the classical stress–dislocation relations and the kinematics of the dynamic recrystallization, the flow stress constitutive equations of the work hardening‐dynamical recovery period and dynamical recrystallization period were established for 4130 steel, respectively. The validity of the model was demonstrated by comparing the experimental data with the numerical results. The agreement of this comparison is quite reasonable.

Microstructure and Mechanical Properties of 34CrMo4 Steel for Gas Cylinders Formed by Hot Drawing and Flow Forming

“…The dynamic recrystallization characteristics of 34CrMo4 steel were investigated by hot compression tests at a temperature range of 900–1100 °C, a strain rate range of 0.001–0.1 s −1 , and a strain of 0.9 [3,7]. For the mechanical properties of 4130 steel, hardening behaviors until high strain rates of 10 3 s −1 and at elevated temperatures up to 1000 °C have been investigated by many researchers [8,9]. Recently, the stress–strain curves at various strain rates for 4130 steel were described with the modified Lim–Huh model, which includes the thermal softening effect [10] and the hyperbolic sine law in an Arrhenius-type equation [11].…”

Hot Deformation Behavior of Ultra-Fine Grained Pure Ti

“…The modeling effort follows a dislocation density based approach, suitable in describing the flow behavior in terms of work hardening (WH), dynamic recovery (DRV) and dynamic recrystallization (DRX) regions. This technique is based on Avrami's formulation and has been utilized in various hot deformation studies and calculation details can be found elsewhere [7]. The fundamental flow stress relations used are:…”

“…It is well known that study of flow stress behavior at elevated temperatures is crucial for the adjustment of warm and hot working process parameters leading to improved workability. These characteristics were previously investigated for pure Ti and other metallic materials [6][7][8][9]. Among them, few studies mentioned the hot deformation characteristics of pure Ti at elevated temperatures [6,8,9].…”

“…Various constitutive equations based on dislocation density evolution during hot forming have been developed from the experimentally measured data to describe the sensitivity of the flow stress to the strain [7,10]. These works gave decent agreement in modeling the flow behavior of 4130 steel [7] and pure titanium [8,9].…”

“…Various constitutive equations based on dislocation density evolution during hot forming have been developed from the experimentally measured data to describe the sensitivity of the flow stress to the strain [7,10]. These works gave decent agreement in modeling the flow behavior of 4130 steel [7] and pure titanium [8,9]. The objective of this work is to provide an insight into the elevated temperature characteristics of severely deformed pure Ti along with efforts to simulate the experimental flow response.…”