The effect of local high-speed intense dynamic action by a metal object (indenter) on the change in the structure of the weld metal of highstrength alloy steel welded with nitrogen austenitic flux-cored wire has been studied. It is established that after welding the structure of the weld metal consists of austenite and delta-ferrite (3 vol. %) with microhardness HV0,1 200-250. After intense dynamic action, the weld metal is strengthened by the mechanism γ ε α’ due to work hardening and the formation of deformation in the structure of α’-martensite in the amount of 10 vol. 5 and a small amount of ε-martensite while maintaining the original amount of δ-ferrite, with an increase in microhardness by more than 1.7 times from the initial level.