EFFECT OF AMPLITUDE AND FREQUENCY OF PLASMATRON OSCILLATIONS ON CHEMICAL AND STRUCTURAL INHOMOGENEITY OF METAL DEPOSITED BY PLASMA-POWDER METHOD

摘要

Effect of amplitude and frequency of plasmatron oscillations on formation of deposited beads, nature of base metal penetration as well as structural and chemical inhomogeneity in zone of joining of deposited and base metals was investigated. The plasmatron oscillation frequency has the largest effect on bead shape and its microstructure, increase of amplitude rises bead width and decreases its height. Effect of plasmatron oscillation frequency on nature of base metal penetration and chemical and structural inhomogeneity in zone of joining of base and deposited metals along surfacing direction was also investigated. In deposition with plasmatron oscillations there is a wavy configuration of interface of deposited and base metals in longitudinal direction with higher frequency of projections and cavities, which repeats plasmatron oscillation frequency. It is determined that increase of plasmatron oscillation frequency on projections as well as cavities in fusion line promotes decrease of deposited and base metals stirring and content of main alloying elements rapidly changes.