Enhancing aluminum casting efficiency through real-time optical fiber sensor monitoring at the metal-mold interface

This study focuses on the critical aspect of interfacial heat transfer during the solidification process in metal casting, aiming to optimize these manufacturing processes. Fiber-optic sensors were employed to provide continuous real-time monitoring of mold gaps and temperature profiles during the solidification of A356 aluminum in a permanent mold-casting environment. A specially designed mold system, constructed from unheated, uncoated tool steel, facilitated the seamless integration of these advanced fiber-optic sensors. One key technique used was the Extrinsic Fabry-Perot interferometric (EFPI) sensor, which uniquely utilized molten metal as the second reflection interface for measuring mold gaps. This method yielded impressively accurate results, with a maximum error of just 2μm compared to physical measurements. Additionally, using the Rayleigh backscattering (RBS) technique, a stainless steel-encased fiber provided real-time temperature measurements with an impressive spatial resolution of 0.65mm. The study demonstrates that combining high-resolution temperature profiles with gap evolution measurements significantly enhances our understanding of heat transfer dynamics at the mold-metal interface, proving particularly beneficial for optimizing complex-shaped castings and continuous casting processes. Furthermore, the capability to monitor the shape of the casting in real-time as it exits a continuous casting mold introduces a novel tool for quality control and process safety improvement by early detection of conditions that might lead to slab cracking and breakouts, ultimately enhancing overall process efficiency and reliability.