Fundamental studies on molten aluminum-water explosion prevention in direct-chill casting pits

Explosive interactions between molten aluminum and water have been studied with a focus on fundamentals to determine what causes robust-enough triggers for explosion onset, as well as to determine the extent of protection provided from various coatings, and to develop a novel methodology for prevention. The steam explosion triggering studies (SETS) facility was designed and constructed as a rapid-turnaround, cost-effective, and safe means to address these phenomenological issues and to derive quantitative, `practically-fundamental' data for situations covering melt masses relocating over submerged surfaces ranging up to approximately 1000 kg (2,000 lb.). Test data obtained from the SETS facility correlated extremely well with past industry data. Explosion onset was determined to result from a combination of factors related to wettability, degree of wearoff, bare spots, charring, existence of bypass relief pathways and non-condensible gases (NCGs). Of these, NCG generation or injection was found to be the most important and overwhelming leading to development of a potentially-novel methodology for cost-effective, environmentally benign and conclusive explosion prevention. Significant data was also obtained on coating durability, as well as on relevance of external shocks, impact of bare spots, and impact of increased melt mass on explosion intensity.