In the paper, the characteristics of the material damageability of the welded joint of high-strength steel with a ferrite-pearlite weld are considered. The hardness measuring of the welded joint surface and mathematical modeling of the obtained results was carried out according to the LM-hardness method. The macrohardness of the surface layer does not allow to fully evaluate the characteristics of the welded joint material, in contrast to the analysis of the degree of degradation of the material by the scattering of macrohardness according to the LM-hardness method. The nature of the increase in macrohardness in the zone of thermal impact indicates the heterogeneity of the material's properties and the likelihood of its damageability for specific experimental conditions. The tendency to technological damageability of the metal samples decreases with distance from the axis of the weld. At the same time, the LM-hardness method allows us to identify individual areas with a tendency to technological damageability of the base metal outside the thermal impact zone. This indicates the possibility of identifying the dimensions of the zone of thermal deformation effect of the welded joint. The number of indicators of the homogeneity criterion of the material used to assess the degree of its damageability is inversely proportional to the distance to the axis of the weld. It is determined by the operation conditions of the joint or product.