The object of research is the effect of the deformation curve on the stress-strain state of the steel elements in the vicinity of the crack. Methods. The study is based on a finite element solution of the elastic-plastic state of a set of samples. The sample is a plate with a thickness of 0 and 20 mm with two edge cracks from 10 to 40 mm long. The results of the analysis are obtained for a bilinear strain curve and a power-law strain curve for different sample parameters. The discrepancy between the parameters of the stress-strain state in the vicinity of the crack tip for different material deformation functions is in the range from 0.3% to 4.7%. This discrepancy estimate allows you to make a decision about choosing a material deformation model for further investigation of the state of the material in the vicinity of the crack. the discrepancy graph of the parameters of the stress-strain state shows the degree of influence of the type of deformation curve within different parameters of the sample.