The mechanical behaviours of microalloyed and low-carbon steels under strain reversal were modelled based on the average dislocation density taking into account its allocation between the cell walls and cell interiors. The proposed model reflects the effects of the dislocations displacement, generation of new dislocations and their annihilation during the metal-forming processes. The back stress is assumed as one of the internal variables. The value of the initial dislocation density was calculated using two different computational methods, i.e. the first one based on the dislocation density tensor and the second one based on the strain gradient model. The proposed methods of calculating the dislocation density were subjected to a comparative analysis. For the microstructural analysis, the high-resolution electron backscatter diffraction (EBSD) microscopy was utilized. The calculation results were compared with the results of forward/reverse torsion tests. As a result, good effectiveness of the applied computational methodology was demonstrated. Finally, the analysis of dislocation distributions as an effect of the strain path change was performed.

基于平均位错密度，考虑了微合金钢和低碳钢在孔壁和孔内部之间的分配，模拟了其在应变逆转下的力学行为。所提出的模型反映了位错位移，新位错的产生及其在金属形成过程中的an灭的影响。背应力被假定为内部变量之一。使用两种不同的计算方法来计算初始位错密度的值，即，第一种基于位错密度张量，第二种基于应变梯度模型。对拟议的计算位错密度的方法进行了比较分析。对于微观结构分析，利用高分辨率电子背散射衍射（EBSD）显微镜。将计算结果与正向/反向扭转测试的结果进行比较。结果，证明了所应用的计算方法的良好有效性。最后，对位错分布作为应变路径变化的影响进行了分析。