Engineering of critical cast parts made of high-strength cast iron based on world experience. Report 2. Investigation of mold properties, melting technology development, and production of experimental castings

This paper presents the results of practical implementation of reverse engineering for critical ductile iron castings operating under high-pressure hydraulic loading conditions. The study examines specific aspects of ductile iron melting and reports casting results using 3D-printed sand-resin molds. Key mold properties including strength, gas permeability, and gas evolution – all critical for final product quality – were thoroughly investigated. Through comprehensive market analysis of 3D-printed mold suppliers and experimental testing, 3D-Fab Sandforms (a division of NPO 3D-Integratsiya LLC, Moscow) was identified as the optimal supplier, offering the best combination of these essential properties. The authors analyzed methods for reducing surface roughness of internal as-cast channels in the component. Dispersed graphite was selected as the coating material for mold cores forming these complex internal channels, with application methods (brushing or spraying) specifically evaluated. The paper details the ductile iron melting process in a PPI-0.02 thyristor-controlled induction crucible furnace, including charge material selection and optimal addition parameters for Sferomag 611 and SIBAR 4 modifiers. This work demonstrates a successful case study of casting engineering, providing practical implementation guidelines for serial production of unique components. The described methodology offers valuable insights for import substitution initiatives in foundry production.