Speaker
Description
White spot defects continue to present a serious risk for critical components in aerospace (and other) applications where material integrity is essential. Despite more than 50 years of investigation into white spots and related segregation defects in alloys such as Inconel 718, their precise origins and reliable prevention remain only partially understood. Even with advanced melting practices, including triple melt routes, these defects persist due to complex formation mechanisms and limited visibility into melt conditions during the Vacuum Arc Remelting (VAR) process.
This presentation provides a review of the primary mechanisms behind white spot formation, including discrete (clean and dirty), dendritic, and solidification-related. It also examines the source of foreign object contamination, such as iron particles and tungsten carbide fragments, and their impact on metal quality. These contamination pathways represent practical risks that can have significant downstream consequences, as demonstrated by the uncontained engine failure on American Airlines Flight 383 in October 2016.
Based on this survey, it is evident that traditional process controls alone do not fully address the root causes of white spot formation. The literature consistently points toward improved measurement of process conditions and tighter control of melt parameters—particularly arc dynamics and heat flux—as key drivers of melt pool behavior. These factors directly influence melt pool stability and solidification conditions.
To address these challenges, we introduce VARmetric™ and ARControl™ as a combined approach to process monitoring and control. VARmetric™ provides real-time insight into arc behavior and melt conditions through high-resolution magnetic sensing while ARControl™ actively manipulates the arc dynamics to control the heat flux distribution. Together, these technologies have been shown to enable the stabilization of the melt pool while tailoring of the solidification front, offering a practical path toward reducing the risk due to white spots and improving the quality of VAR-processed materials.
| Speaker Company/University | CONSARC - An Inductotherm Group Company |
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