Technique des fonderies

This course document provides a comprehensive introduction to foundry techniques and molding processes aimed at engineering students. The first part presents the fundamentals of foundry practice, beginning with definitions, organizational structure, and material and process flow within a foundry. It details the possibilities and specificities of casting, including mass range, geometric complexity, dimensional accuracy, surface finish, and applicable alloys. A systematic classification of molding processes is given, covering traditional methods such as sand molding (silico-argillaceous and cement-bonded) and permanent mold casting (gravity, pressure, and centrifugal casting), as well as modern and special processes, including hot- and cold-setting sand techniques, plaster molding, shell molding (Croning), the Shaw process, and lost-pattern molding. Metallurgical and thermal phenomena during solidification are examined at both the crystalline and macroscopic scales, with particular attention to structural and chemical heterogeneities and fluidity. Environmental aspects are addressed through a discussion of solid, atmospheric, and aqueous emissions, and approaches to cleaner foundry technologies. The second part focuses on casting defects, their classification, origins in liquid, solidification, and solid-state shrinkage, and corresponding remedial measures. Finally, the document presents non-destructive testing techniques for detecting external and internal defects, including visual inspection, liquid penetrant testing, magnetic particle inspection, radiography (X and γ rays), and ultrasonic testing, with emphasis on principles, equipment, and practical implementation.