Purpose: During weld metal structure formation the possibility of impact on its mechanical properties are much more limited in comparison with metallurgy and technology of steel production. Adding of the inoculants to the welding pool is one of the promising methods of influencing the structure and mechanical properties of the weld metal. Design/methodology/approach: Cellular automata (CA) with additions of finite difference method (FDM) is one of the best ways to simulate dendritic growth process with the surfaceactive inoculants. It`s easy to add new rules of interaction between the inoculants and dendrite surface to the cellular automata model. Findings: It was found that average distance between primary dendrites axis decrease with increase of the inoculants wetting angle by melt iron. Obtained results were confirmed experimentally on weld metal samples that were obtained by the welding of HSLA steels with the surface-active inoculants. Research limitations/implications: The inoculants with size that comparable with cells size of the model (≈0.4 microns) were distributed evenly in computational area. Practical implications: Adding of surface-active inoculants to the melt metal improve structure and mechanical properties of weld metal. Different refractory particles (TiC, TiN, SiC, TiO2, Al2O3 and ZrO2) can be used. Originality/value: Refractory inoculants adding to the melt metal are wide used in metallurgy as crystallization centers and heat absorbers. Inoculants that were added to the welding pool of high-strength low-alloyed (HSLA) steel welds could also influence on crystallization processes of weld metal as surface active particles. In the contact point between the dendrite surface and the surface-active inoculant, a surface energy is change depending of the inoculant surface properties. Different refractory particles (TiC, TiN, SiC, TiO2, Al2O3 and ZrO2) were used.