Systems for recycling overspray powder during spray forming

摘要

A system for the recycling of overspray powder during spray forming is provided. The system involves providing a refining vessel to contain an electroslag refining layer floating on a layer of molten refined metal. An ingot of unrefined metal is lowered into the vessel into contact with the molten electroslag layer. A current is passed through the slag layer to the ingot to cause surface melting at the interface between the ingot and the electroslag layer. As the ingot is surface melted at its point of contact with the slag, droplets of the unrefined metal are formed and these droplets pass down through the slag and are collected in a body of molten refined metal beneath the slag. The refined metal is held within a cold hearth. At the bottom of the cold hearth, a cold finger orifice permits the withdrawal of refined metal from the cold hearth apparatus. The refined metal passes from the cold finger orifice as a stream. The stream is atomized for spray forming into a preform article on a spray collection station having a solid receiving surface for receiving the atomized metal thereon to form the preform article. The powder produced during the atomization which was not deposited on the solid receiving surface of the spray collection station is recycled onto the top of the molten slag in the electroslag refining station.