Hot Flow Stress Models of the Steel C45

Vocabulary flashcards covering the experimental materials, models, and parameters used in the hot flow stress analysis of C45 steel.

Steel C45

A medium-carbon steel with an indicative chemical composition of $0,42$-$0,50\,\text{wt.\%}$ Carbon and $0,50$-$0,80\,\text{wt.\%}$ Manganese.

HDS-20

A thermo-mechanical simulator (Hot Deformation Simulator) based on the concept of the plastometer Gleeble 3 800 used for uniaxial hot compression testing.

Uniaxial hot compression test

A plastometric experiment used to obtain flow stress curves to determine the natural flow stress of an alloy and select suitable forming equipment.

Hensel-Spittel model

A phenomenological model used for universal flow stress prediction, expressed by the equation: $\sigma = p_1 \exp(p_2 t) \cdot t^{p_3} e^{p_4} \cdot \exp\left(\frac{p_5}{e}\right) \cdot (1+e)^{p_6 t} \exp(p_7 e) \cdot \dot{e}^{p_8} \cdot \dot{e}^{p_9 t}$.

Schindler model

A mathematical model that describes flow stress with respect to the start of dynamic recrystallization: $\sigma = p_1 e \exp\left( \frac{p_2}{e} - p_3 \cdot e \right)^{p_4} \cdot \exp(-p_5 \cdot T_K)$.

Peak strain ($e_p$)

A value reflecting the influence of the start of dynamic recrystallization on softening processes, described for Steel C45 as $e_p = 0,00335 \cdot Z^{0,186}$.

Zener-Hollomon parameter ($Z$)

A parameter related to strain rate and temperature, calculated as $Z = \dot{e} \cdot \exp\left( \frac{Q}{R \cdot T} \right)$.

Activation energy ($Q$)

The energy required for hot forming of the given steel, determined to be $280\,kJ\,mol^{-1}$.

FORGE

A FEM simulation software that works with the Hensel-Spittel model in a standard manner for predicting flow stress.

Steady-state area

The area of the stress-strain curve where flow stress remains constant; both the Hensel-Spittel and Schindler models encounter problems describing this area during extrapolation to high strains.

UNISTAT 5.6

The software used in this study to calculate material constants of models via multiple nonlinear regression analysis of experimental data.