Deoxidation of Ti Melt by Newly Developed Two-Step Plasma Arc Melting Process Using Hydrogen

Recent Studies on Titanium Refining: 2017–2020

“…A two-step plasma-arc-melting process (the first step was under Ar30% H 2 gas flow, and the second step was under Ar gas flow) was effective for the deoxidation of Ti melts. 117) The oxygen content after arc melting decreased from 1.5 to 0.7 mass% at the surface of the melt.…”

“…116) Once metallic Ti is formed, the next problem is residual oxygen. Oxygen removal from TiSi melts during arc melting was investigated by Watanabe et al 117) The oxygen in the Ti(2330 mass%)Si ingots was removed as gaseous SiO during melting. Enhanced uniformity of oxygen distribution in the metallic liquid was achieved under the flow of He gas rather than Ar gas because the melted region was extended toward the depth direction when using He gas.…”

Recent activities of titanium research and development in Japan

“…A new two-step plasma arc melting process for oxygen removal from Ti melts, comprising Ar-H 2 plasma arc melting (first step) and subsequent Ar plasma arc melting (second step) was proposed ( Fig. 10) and change in the oxygen content of Ti melts was reported [16]. The deoxidation reaction of Ti melts occurs in the second step and is expressed by Eq.…”

“…Figure 11 depicts the oxygen content after the two-step plasma arc melting. The oxygen content in the surface region of the Ti melt decreased from the initial value of 1.5-1.6 mass% to ~0.7 mass% [16]. Further, Ti deoxidation with Al addition during melting was developed.…”