Thermal Analysis in Iron Casting: From Metallurgical Understanding to Advanced Process Control
Thermal analysis has become one of the most effective and widely adopted tools for process control in iron foundries. By analysing the solidification and cooling behaviour of molten metal, foundries can obtain valuable information about chemical composition, metallurgical quality, nodularity, feeding behaviour and final material performance.
AZTERLAN has contributed a consecutive series of technical articles to the Foundry Trade Journal (FTJ), a specialist publication dedicated to the foundry industry, its technologies and manufacturing processes. Across the series, AZTERLAN explores the principles, industrial applications and advanced process control opportunities enabled by thermal analysis.
Together, these publications provide a comprehensive overview of how thermal analysis can help foundries improve quality, increase casting yield, reduce costs and move towards more predictive and data-driven manufacturing strategies.
Authors:
Beñat Bravo (AZTERLAN), Iker Asenjo (AZTERLAN), Ander Areitioaurtena (AZTERLAN)
Related contents:
1.- Use of Thermal Analysis in the Iron Foundry: Basic Principles
The first article introduces the scientific foundations of thermal analysis and explains how cooling curves can be used to characterise cast iron during solidification and solid-state transformations. It describes the relationship between thermal events and key metallurgical parameters.
The article also demonstrates how thermal analysis enables foundries to move beyond traditional chemical control by extracting additional information from the solidification process itself. Particular attention is given to the interpretation of liquidus and eutectic temperatures, the influence of alloying elements and the prediction of microstructural characteristics from thermal data.
Key topics covered:
- Thermal analysis fundamentals and cooling curve interpretation.
- Determination of carbon equivalent and silicon content.
- Stable and metastable solidification systems.
- Influence of alloying elements on solidification behaviour.
- Prediction of final matrix structure through eutectoid transformation analysis.
2.- Use of Thermal Analysis in Iron Casting: Main Applications
The second article focuses on the practical implementation of thermal analysis in productive processes and presents real industrial applications demonstrating its value for metallurgical control. It explains how thermal analysis systems can be integrated into melting and pouring operations to provide rapid, objective and actionable information for process management.
Industrial case studies illustrate how thermal analysis can be used to control active magnesium levels, monitor nodularity, assess metallurgical quality and optimise inoculation practices. The reported results show significant improvements in process stability and substantial reductions in consumable usage and production costs.
The article also highlights the increasing integration of thermal analysis data with intelligent manufacturing systems, creating new opportunities for predictive process control and defect prevention.
Key topics covered:
- Carbon and silicon estimation.
- Active magnesium control in ductile iron.
- Nodularity control in compacted graphite iron.
- Metallurgical quality assessment prior to pouring.
- Industrial case studies demonstrating cost savings and process optimisation.
- Integration with intelligent process management systems.
3.- Metallurgical Quality-Based Predictive Simulation for the Ductile Iron Foundry: Improving Process Control and Casting Yield
The third article presents an advanced approach that combines thermal analysis with predictive simulation tools, integrating metallurgical quality parameters directly into casting simulation models. The methodology enables foundries to quantify the self-feeding capacity of ductile iron and improve the prediction of shrinkage formation and casting soundness.
A featured case study demonstrates how thermal-metallurgical analysis made it possible to replace a conventional two-riser feeding design with a single riser while maintaining casting integrity. Validation through computed tomography and metallographic analysis confirmed the accuracy of the predictions and highlighted the potential for significant yield improvements.
The article proposes a new design philosophy in which metallurgy becomes an active input to predictive simulation rather than a background assumption, enabling more reliable decisions and more efficient feeding system designs.
Key topics covered:
- Integration of metallurgical quality into casting simulation.
- Prediction of self-feeding capacity and shrinkage behaviour.
- Optimisation of feeding systems and riser design.
- Industrial validation using computed tomography and metallography.
- Improved casting yield, process reliability and manufacturing efficiency.
