In this publication we provide experimental data of dynamic compression tests of four microstructural variants of the C45 steel alloy performed at high temperatures and high strain rates. The presented data evidences the presence of Dynamic Strain Aging (DSA) in the material. Moreover, we provided the MATLAB codes of a calibration approach to estimate the material parameters of a plasticity model that accounts for DSA. The file "Mechanical behavior of C45" contains: 1) Folder EXP_DATA contains experimental data of dynamic compression tests of the C45 steel variants in .mat format. The data is organized in cell arrays, and every cell in the arrays contains the data of one experiment. The data of each experiment is arranged as four columns arrays, as: column 1: Plastic strain, column 2: Flow stress, column 3: absolute temperature, column 4: strain rate 2) Matlab code named CALIBRATION.m which executes a calibration approach of a modified Johnson-Cook that accounts for DSA. The form of the model is the following: \(\sigma(\varepsilon ,T,\dot{\varepsilon}) = (A+B\varepsilon^n)\left(1+Cln\left(\frac{\dot{\varepsilon}}{\dot{\varepsilon}^{ref}}\right)\right)\left( 1-\left(\frac{T-T^{ref}}{T^{melt}-T^{ref}}\right)^m\right) +\sigma^{dsa}(\varepsilon ,T,\dot{\varepsilon}) \) with, \(σ^{dsa} (ε,T,\dotε )=\frac{B_1}{ν} \left(\frac{ε^β}{ ε ̇T} exp⁡(-\frac{Q_m}{KT}) \right)^{\frac{2}{3}}\), \(\frac{B_1}{\nu} = \frac{\psi \dot{\varepsilon}}{exp(\eta \frac{T}{\dot{\varepsilon}^\alpha})} \) The code CALIBRATION contains a data presentation section that can be used to generate plots to compare calibrated models with the experimental data. Further instructions are commented in the code CALIBRATION.m.