The influence of the “saw-tooth” type electron beam sweep on the penetration shape during electron-beam welding of 30KhGSA high-strength steel with different welding modes was investigated. Using the instrumented indentation method, the distribution of Young’s modulus, as well as the characteristics of strength and plasticity in the welded joints cross-sections, was obtained. It has been found that in the weld metal there is a sharp increase in strength characteristics, while the plasticity ones are significantly reduced. The values of the Young’s modulus also varied over the cross-sections. The considerable decrease in this characteristic (up to 20%) was registered in the weld metal in comparison with the parent metal results.