Titanium Nitride (TiN) Germination and Growth during Vacuum Arc Remelting of a Maraging Steel

Abstract

During the processing of maraging steels, Titanium easily combines with Nitrogen to form nitride inclusions, known to be deleterious for fatigue properties of the alloy. According to thermodynamic calculations, the precipitation occurs during solidification of the vacuum arc remelted (VAR) ingot. A coupled model of titanium nitride (TiN) inclusion precipitation and vacuum remelting has been set-up to study the inclusion cleanliness of the ingot. The nitrogen content, nuclei numeral density and solidification time appear as the key factors which control the inclusion size.

Keywords

• nucleation
• TiN inclusions
• maraging steel
• VAR process