It is studied stress relaxation at microstructure modeling, in particular percentage of rolling reduction and relaxation time at forming microstructure. For the specimen ingot is given a stress in hot-rolling method at temperature of 250°C. The variable parameter is 1, 2and 3% bulk reduction during rolling; loading duration is 0.5 – 3.5 s. Tensile test is used to measure the tensile strength. Knowing the initial time of grain formation, we state the initial and final moments of precipitate during recrystallization. The microstructure analysis is performed by using Scanning Electron Microscopy (SEM). The research results show that in the case of 1% bulk reduction during rolling, there is a microstructure recovery in the first 0.5 s, then recrystallization begins via 1 sec, the beginning of precipitation takes place after1.5 s, and grain growth begins after 2.5 s. Corresponding results for 2% bulk reduction during rolling: recrystallization begins via 0,5 s, the beginning of precipitation takes place after 1 sec, and grain growth begins after 2.5 s. The results for 3% bulk reduction during rolling: the beginning of precipitation takes place after 0.5 sec, and grain growth begins after 1.5 s.