High temperature flow behavior and constitutive model of alloy transition layer in composite steel tube prepared by centrifugal self‐propagating high‐temperature synthesis (SHS)

Abstract

Centrifugal self-propagation high-temperature synthesis (SHS) is a newly developed composite preparation technique by which a ceramic-alloy-carbon steel multilayer composite tube can be prepared. The hot deformation behaviors of the alloy steel layer at 800°C-1000°C, strain rates of 0.01 s À 1 , 0.1 s À 1 , 1.0 s À 1 and 10 s À 1 were studied by Gleeble-1500 thermal simulator. Rheological curve characteristics were analyzed under different thermal compression processes and a phenomenological hyperbolic sinusoidal Arrhenius constitutive equation was established to characterize the rheological mechanics of the material. The results show that the alloy steel is sensitive to temperature and strain rate, and its value of true stress decreases with the increase of temperature and strain rate. Thermal deformation process is the interaction between work hardening and dynamic softening, which is accompanied by the increase and extinction of dislocations. Under the strain rate of 10 s À 1 , the stress-strain curve has a significant decrease when the strain exceeds 0.5. According to the observation of microstructure, this phenomenon can be attributed to the micro-crack generated by the local instability flow in the denatured zone. With the strain rate decreases, the softening mechanism of the alloy changes from dynamic recovery to dynamic recrystallization. The calculation results of the Arrhenius constitutive equation (AARE = 6.54 %, R = 0.99452) indicate that the model can predict the flow stress of the alloy accurately.

Strain Modified Constitutive Equation and Processing Maps of High Quality 20MnCr5(SH) Gear Steel

“…The strain modification of the Arrhenius constitutive equation is theoretically beneficial to improve the accuracy of flow stress prediction. Wang et al [8] established the high temperature flow stress constitutive equation for alloy transition layer in composite steel pipe, and expressed the material parameters in Arrhenius constitutive equation with quintic equation group, and the fitting correlation is above 0.97847. Zhao et al [9] carried out a hot compression experiment on 40CrNi steel, and established octave equations about strain according to material parameters.…”

Numerical analysis of flow behaviour, grain size prediction and experimental verification of hot rolled ultralow carbon niobium microalloyed steel

“…There are significant studies on various alloys and approaches to produce martensitic dual phase steel [8]. It can be produced by reheating the cold rolled sheet within the inter critical temperature range, the austenite-ferrite phase (α + γ), followed by quenching [9]. As an alternative, dual-phase steel can be economically produced by hot deformation method starting with an austenitic microstructure followed by quenching [9].…”

“…It can be produced by reheating the cold rolled sheet within the inter critical temperature range, the austenite-ferrite phase (α + γ), followed by quenching [9]. As an alternative, dual-phase steel can be economically produced by hot deformation method starting with an austenitic microstructure followed by quenching [9]. Compact slab production technology offers an economic way to produce a hot rolled strip with characteristics comparable to those of a cold rolled material [10].…”