Ti and TiAl melting with a semi-industrial PAMCHR

Abstract

Upscaling from laboratory trials to industrialization is a critical step in the development of new metallurgical processes and products. Pilot trials are an important way to provide data that can be used to better understand and model the industrial-scale process. MetaFensch has invested in a semi-industrial Plasma Arc Melter Cold Hearth Refiner (PAMCHR) in order to support the development of the recycling of titanium scraps into aeronautical grade titanium alloy ingots. This pilot supports the industrial scale PAMCHR of the company Ecotitanium in the frame of a collaborative project with Aubert & Duval and Safran as industrial partners. The work done on the pilot scale PAMCHR consists in studying the influence of various parameters like the type of melting feedstock, plasma arc parameters, operating pressure on the final quality of the cast ingot. The goal is to understand the physico-chemical mechanisms involved in the plasma arc interacting with the liquid metal in order to optimize the melting and refining parameters for the industrial scale furnace Ecotitanium (Ti64 alloy). Ti64 and TiAl ingots were cast in 150 mm and 100 mm diameter. Chemical composition and solidification structure were characterized. The effect of the different process parameters on the titanium melt and on the ingot quality are studied. Examples of exploitation of the thermograms obtained with the thermal camera situated above the refining cold hearth will also be presented in this paper.