Effect of wave motion on chill cast surfaces
The formation of exterior surface ripples, and their dependence on filling rate and superheat, was studied in bottom-poured ingots of low melting Sn-Pb alloys. It was found that surface waves in the liquid metal during mold filling are the basis for an important mechanism leading to formation of the primary exterior ripples. Imposition of a steady D. C. magnetic field strongly dampens the surface waves in the liquid metal, essentially eliminating the primary ripple marks throughout the bottom two-thirds of the ingots. The magnetic field also enhances columnar grain growth.