The influence of electron beam oscillation on the crystallization and structure of dissimilar steel-bronze welds

Abstract

The paper contains the findings of the metallographic study of dissimilar metal welds (steel 12X21H5T and bronze BrX-06) made by electron-beam welding (EBW) with beam modulation (transversal and X-shaped oscillation with triple beam splitting). The research shows that beam oscillation causes the metals to stir in the weld pool. As a result, welds have a very heterogeneous structure by width. X-shaped oscillation causes more intensive stirring than transversal oscillation. This leads to more homogenous stirring of crystallizing phases in the centre of the weld. The heterogeneous structure caused by beam oscillation gives the weld a very heterogeneous solidity both by width and depth. Triple beam splitting heated from bronze promotes the homogenous weld structure which is a fine-dispersed mechanical mixture of two systems: a eutectic based on copper and a mixture of solid solutions based on [alpha]-Fe and [gamma]-Fe. Such a structure makes the weld equalizes the solidity of the weld both by width and depth.